Tinkering

Aikido Pre-Amp Project - part 9

2011-10-07T19:43:00.002+08:00

My brother came with a home-made chassis; Something my brother designed some years ago. 18"x12"x 4" high.
This is the chassis after a quick clean up.

This will be a great time saver since I've already spent nearly 60hrs on the project & any quick solution put things back into prospective.

This is the new amendment to the layout.

Ample real estate available.
As I'll not use a separate base plate for mounting the irons, it will be difficult to mount the previously selected irons. So I've change the 2 transformers to vertical mount type EI laminate tranny.
Since he don't require source selection, so the selector switch is obmitted.
Now, I need to find suitable IRC sockets that will fiit the opening already on the chassis.
I'll fill in the common mode filter & other switches & socket when I can find more time for it.

Aikido Pre-amp Project - Part 8

2011-10-02T14:12:00.002+08:00

It is easy to get carried away & fall pray to unnessary desires & unrealistic wants.

Time to put on my contractor hat & give the whole PSU a final round of scrutiny.

Keep-It-Simple-Stupid....

Virtual capacitor
I have never suffer premature valve failure other than applying brute force with a blunt object on them... I've yet to see any valve died of voltage stress... Seriously, what can 30ma current surge do??? or even 300ma??? Tubes are built to take brutality like fish in water!!! So it will reduce the valve life from 200,000 hours to 180,000hour... so what!?
Aikido were born with PS ripples cancellation. Let them do what they do best!
This is a class A1 amp, the load behaviour is almost a constant current and the signal source will most likely be solely fed from a CD player or a DAC with 2Vrms signal, it will never come close to clipping! Moreover, since it is not a power buffer stage with transformer coupling, high power supply Zo is not a real issue.

Why bother with the extra works when one can get away with it???

Another visit to PSU2 & came up with these component numbers, the damping is sightly over 1 which is where my preference lies.

and the following is what I'll build.

Final check,

A costumed RFI/EMI common-mode filter,
All important last line of defence, 0.1A fuse,
The indispensable power rocker switch,
Obviously essential IEC power socket,
A spikes treated rectifier bridge,
A snubber treated choke,
A CLC network which gives a well damped & quiet B+,
A floated AC filament supply with twisted solid core leads.

This should put everything back in prospective & an end to the PSU design...

<<<<>>>>

Another look at the chassis...

Aikido Pre-amp Project - Part 7

2011-10-01T14:46:00.001+08:00

Correction....

My bad..... Made a blunder with the capacitor multiplier schematic in the last post...

This is the correct schematic.

I forgot about the potential divider for biasing the MOSFET. My bad.

In doing so, we will reduce the B+ by 5% & also provide a short term regulation of +/-10%. Hence, smooth out sudden mains voltage fluctuation within to 5%.

In the long term sense, the B+ will track the mains voltage fluctuation.

Under New Management

In this new arrangement, the gyrator is after the CLC network filter, just like how everyone else arrange their voltage regulator.
Since we happened to have a gyrator in the circuit. Might as well let them do what they do best i.e. reduce Zo to single digit & excellent ripple reduction.
Now I can reshuffle the component values of the CLC to achieve the damping factor which I am looking for, highest B+ possible & lessen capacitance further.
Added a 220R 5W resistor in series to the choke, this was not an option earlier as it will add on the PSU Zo, with this, I can reduce 120uf to 47uf.
I could had use 10uf at the last cap, but the gyrator only mimic a huge capacitor without actually storing any real energy, so using a 47uf as reservoir seems reasonable.
Also, 3 more snubber capacitors for the rectifier, now, there is a snubber cap for every diode in the bridge rectifier. This will work better yet still not too much work...

We loss about 15V on the B+ with the gyrator & CLC amendments, but I consider that a bargain with the added slow-ramp, cleaner, stable B+, better damping pattern & reduced Zo significantly.

..........PREVIEW Part 8..........

Closure

Aikido Pre-amp Project - Part 6

2011-09-30T20:01:00.001+08:00

We have bulldozed this far where we had enough numbers & design plans to start building.

Arfter simmering the whole battle plan for a few day; Lets give it a trim.

PSU Sanity Check

Since I decided on a PCB, I'll just let it free from hacking for now, that leasves only the PSU to comfort my bloated ego...

For the choke, a snubber is added for taming stray capacitance of the choke, also a diode for safety.

This bridge ractifier is build from discrete parts, & the actual parts connections are as shown in the following drawing.

All is rosy until I realised this is too much work for a 12 year old....
So I drop the idea & use a package bridge ratifier instead. BUT there are no free lunch....
We gotta do something about the SS diode switching spike which will back feed into the main transformer secondary coil, induce noise in the primary & this will pass on to the other tranny connected to the same main.

The CLC filter which will not do anything to better the situation, it has to handle at the AC state.

An easier cocktail concoction fix.... Use fast recovery bridge for least switching spikes & connect a small value capacitor across the AC terminals on the Bridge rectifier to tame the naughty spikes, not ideal, but that should get the job done...

No PCB require, the circuit is simple enough for wiring the component point to point.

Wait-up !!!

Tube will not conduct instantly from start up, they will only conduct when heated sufficiently by the filament. Unlike a tube ractifier, our solid state ractifier will not wait for that to happen. This instant high voltage will stress the tube & components. The risk is very especially pronounce with direct coupling circuit, which Aikido is. The consequence is premature death of the tubes concerned or fire..... which is a bad bad thing...

Capacitor Multiplier, A.K.A Gyrator

The conventional wisdom is to throw in a timer delay relay circuit to facilitate time for the heater to raise the tube temperature. This calls for extra components, relays, another power supply for the circuit, breadboarding on perforated board or even making another PCB... Hack, I'm loosing hair just to come up with excuses for not doing it!!!

I'll go without any relays by implement a capacitor multiplier instead. As the name implies, its will mimic huge physical capacitor of your choice value with 1 transistor, 2 resistor & 1 capacitor.

Like a real capacitor, it is very good at reducing ripples (High PSRR). It is not a voltage regulator as it will track the raw voltage & floats on the B+. AND it can reduce the power supply impedance to a single digit which is desirable

All are rosy..... BUT not what I'm after. I am after its 6dB/octave voltage built-up feature. Others are just mare bonuses...

MOSFET is the Chosen One!

BJT requires to pass at least 1ma to the gate, that will limit the size of the R value which make up the RC network ( the 500K & 68uF ) without eating up voltage; MOSFET on the other hand just need to see voltage at the gate without drawing any current, this gives a free hand to the resistor size selection.

Even though MOSFET will need to drop 4V to work, but really, loosing 4V on B+ really isn't an issue here.

Component sellection isn't critical.
Even though the potential across the MOSFET is only a few volts since it is actually floating on the B+. Being SS, they will let out the magic smove if hit by high voltage. Using one with at least the B+ voltage rating is a safe bet. Hence a IRF820 with 500V, 1.2A rating. which I happened to have in my hoard pile.
The 1K resistor acts as the grid stopper of IRF820.
The product of 500k resistor & the 68uF RC network gives time constant of 34 seconds. Since it is a 1st order network, B+ will ramp up to 63%(~189V) in 34seconds. 102 seconds to get to 95% (285V), & nearly 3 minute to get to full B+. Plenty of lead time for the tube to heat up.

That should get the job done...

Let Go Upstream...

Parasitic noise in the mains can stir up a havoc if not kept in checked... Not only we must stop these nasty noise from getting into our equipment. It is even more important to prevent the noise generated in our equipments from getting into the mains & contaminate other equipment sharing the same mains. They usually comes as common mode noise. What it means in layman terms is it is indescrimal & will superimpose themselves on any form of signals.

To reject common mode noise, we can make ourselves some(obviously) common mode filter.

You can make one with ease.

*PS,
Bi-filler wire means 2 wires side by side.

Drum Roll, Please....

Throw in the gyrator, snubbers, filament tranny, 0.1A slow blow fuse, a rocker switch, the IEC socket... & he we have a family portrait.

This ought to do it....

>>>>Part 7 Preview<<<<

Your guess is as good as mine....

Aikido Pre-Amp Project - Part 5

2011-09-28T19:04:00.000+08:00

Some definitions to put thing straight before we proceed further.

~"Cabinet"~
Enclosure use to barricade dangerous/fragile thingy from the public brutality.
It can be a plain container of any shape & material or
with lots of cosmatic & decor for aesthetic reason.
It may be water tight. air tight or fire proof depends on requirements.
Your imagination (or your budget...) is the limit...

~ "Chassis" ~
A structural platform from which we build stuff on. Be it a electrical & electronics appliance or a car. Others prefer to call it skeleton.
material is function & budget dependent...

Public Appearance

Lets examine the "genaric" form the modern Hifi tube-amp use.

Exposed Tubes with a couple of hundrad volt waiting for a good kill.

Anti-Children protection

same mo, same mo...

I highly suspect that cost cutting is at work...

That in my opinion is cheating... anything which has over 50V & conduct 100mA must be properly barricaded from fingers...

~Ye-Olde .....

In the early days of electronics.

Beautifully crafted cabinet encapsulate all high voltage stuff...

This was how they did it once upon a time.

The modern tube guitar amp took up the tradition.....

How I would go about this????

I like these form...

My experience says, stay away from metal works on cosmetic finishing, the cost for the setting up the right gear for high quality consumer grade finishing is not what typical DIY builders would like to put up with.

Wood on the other hand is manageable. The only catch is you gotta commit to generous use of elbow grease for lots of sanding, rubbing & polishing.

Woodpunk Aikido Preamp Cabinet.

This is my preliminary Woodpunk style cabinet.

This cabinet is for 3 chassis. namely, the PSU, PCB & a future DAC chassis.

I tried to keep the valves at least 75mm from any wood. Also, plenty of opening for warm air to escape to prevent localised heating & hence fire in the house.
Instead of using fabric, I will carve as many fretwork possible for ventilation & serve as a art decor... the openings should large enough for unrestricted air flow & small enough to keep itchy fingers at bay. The fretwork should be space strong enough to resist destructive+itchy fingers.

The front panel is finger joint to the bottom.

The back panel does not cover the whole rear end, instead, it leaves a 100mm opening for accessing to the rear end of the chassis. This is good for both fiddling with interconnect & plenty of x-section area for ventilation. The added advantage are added protection to your interconnection cable plug & you can't throw a stone & hit the valves directly :)

3 access opening on the bottem panel for accessing to the chassis separately. This will preserve the structural integrity of the bottom panel and having smaller chassis bottom cover which are easy to handle.

The top, sides, back panel are finger joint together to from a U cover which is detachable. The cover will have sliding grooves on the side panels which can slid into the front penal in the vertical direction.

Choice of wood.... hmmmm... teak is my favorite but they are hard to come by these day, lets keep the selection open for the moment.

Will finish the wood in satin so as to show case the natural wood grain.

IMHO, this has the retro appearance & modern interior...

We have finally come to a solid visual of the finish project.

I'm done for this session....

....Part 6 Preview....

I haven't a clue....

Aikido Pre-Amp Project - Part 4

2011-09-27T21:38:00.001+08:00

Works continue on chassis design...

We will take up where we left in part 3 where we gone as far as determining the required chassis dimension of such,
PCB chassis dimension :141 x 293 x 100mm (H)
~5-1/2" x 11-1/2" x 4" (H)
PSU chassis dimension : 121 x 293 x 100mm (H)
~4-3/4" x 11-1/2" x 4" (H)
Aluminium is the material of choice.

Determine Type of Chassis & its Construction Method
Nothing in my junk pile match the sizes required, not even aluminium metal containers or kitchen utensil which I can improvise.... :(

Instead, I found some 300 x 500 x 2mm thk aluminium sheets which sits on a shelve all by themselves.. These will be suitable for folding a chassis per sheet with some tweaks in the chassis dimension.
Before any further a do, I need details of the press brake that will be folding these chassis for further number twitching in the previous development drawings. A disappointing trip to my friendly neighbourhood sheet metal fabricator reviews that the smallest bending radius is 9mm which is IMHO too coarse for folding chassis with a million-dollar-look

"Desperation is the mother of innovation"

More stock check on what are at my disposal, with a pinch of copy cat & a whole load of cheating... The following drawings appear progressively...

Don't know how you will coin it. Borrowed from wood joinery technique; Its basically a 3D jigsaw puzzle with tabs & tab holes. Tabs & tab holes are employed for locating the panels in relation to each other accurately. They will be spot welded at the tab joints to ensure good electrical & rigid structural bonding.

While I was at it, conveniently added some perforation on the PCB chassis top panel to facilitate ventilation path while preserving the rigidity of the penal. No opening on the side panel as I'm too tired to do so...

Keen eye readers will notice by now that both PSU & PCB chassis are identical in size.

So, I cheated... .Uniformity is the current excuse of choice for my laziness... I am sticking to it.. :)

After burning more man hours on touching up the design with further detailing such as optimising material utilisation; The nested penal layouts were born.

I reckon this will be the eventual construction drawing... but I do expect "unforeseen" circumstances.

The next on the list is to put the design aside to simmer for a couple of days (maybe weeks) while I can go on with my day job. We will know if there are any need for further tweaking by then...

Before I switch off the PC, here are the summery,

~Dimensions~
External : 140(W) x 290(L) x 100mm(H)
~5-1/2" x 11-3/8" x 3-15/16"
Internal : 124(w) x 274(l) x 98mm(h)
~4-7/8" x 10-25/32" x 3-7/8"

~Panel material~
2mm thick Alum Plate which is approximately 14Gauge.

~Construction method~
CNC machined panels with tabs & tab hole, held together by TIG spot weld.

~Finishing~
Wire brushed, with natural colour Anodised.

Another 10 man hour burnt....

Now I can stop staring at the monitor & rest....

...........PART 5 PREVIEW...........

It will be physical!

Aikido Pre-Amp Project - Part 3

2011-09-26T19:15:00.001+08:00

In the previous article, I've came to the following layout.

Commercial amplifiers does has similar form dimension, I will use Pioneer A400 foot print which is 16 1/2" x 12" (420x305mm) as a rough guide.
Layout is not strictly a 2D affair, in the real world, we have 3-dimensions to play with. We can stack irons on each other if I have a magnetic shield between them hence, I'll place the filament transformer under the aluminium plate & have the choke directly above of it without adverse effects.

That leads to Ver.2

We get a huge space at the bottom left corner, plenty of real estate for future additions.

It struck me that if we put the PCB & all the iron is 2 different casing & we get separate PSU arrangement!

But I don't fell comfortable with that huge void in the PCB casing so one thing lead to another, another layout appears...

Here are the other views

I go for a 100mm height chassis for now but 80mm will be the bare minimum for any reasonable working space within the chassis.

All these work just to obtain the dimensions require for chassis preparation, be it off the shelf or custom made. Do you feel why I always end up with chassis-less amp??? LOL!!!

I started with all the intention to produce a 3D model of the chassis, unfortunately, getting to this stage has eaten up over 24 man hours. Since I've got all the dimension required to start construction, I'll have to take a short cut & skip the whole 3D modeling exercise... :(

A description of the 3D chassis instead... :(

PSU Chassis
The mains tranny and the filament tranny will be on top of the PSU chassis & the choke under the filament tranny separated by the chassis top panel. They are space up lavishly.

The void between the two are filled by the filtering circuit component within the casing.

The IEC socket will be on the back panel since all commercial amps has the
On/Off switch on the front panel, I'll follow suit even though I feel like an idiot routing the wire loop from back to front & back again... also... I can use relay & implement remote activation but I don't have one in my junk pile... Lets just keep it simple...

PCB Chassis
The PCB mounted on the bottom of the top panel to keep them away from dust & most importantly exposure to any form of interference.
The tubes protrude through the 4 holes on the top panel for best possible ventilation. I choose to have the tube orientated as such for it is farthest possible from the PSU exposed irons.
Filament wire layout can make or break any tube circuit... they are very high on my priority list. Tug into the chassis corners & away from any signal wire, even if you have to detour. The twisted wire will be travelling along the bottom of the chassis as shown & go vertically into the +H & -H terminals on the PCB.
The signal in & out terminals are on the back panel as shown... Detailing the hole dimension will have to wait...
The selector & volume pot will be located just beside the signal input terminals at the back panel. they are linked to the front panel via separate connecting rods. This is important as the raw input signal is weak, susceptible to noise corruption. The extra wire length will act as antenna to invite noise. For extra protection, tug the wire into the top corner (top & side panel).

Finally! We come to the point where there are enough numbers to proceed with chassis preparation.
Go find ready made chassis of in close proximity of 142x293x100mm & 120x293x100mm & start drilling.
OR

Fabicate from these developement drawings.

WATCH THIS SPACE!!!

Aikido Pre-Amp Project - Part 2

2011-09-25T19:13:00.001+08:00

In this post I'll go about the chassis layout.
This is going to be boring.... but its absolutely crucial for one to get this right before any physical work...

Again, I would lay down the requirement for this session
1) Safety
2) Hum free
3) Easy construction
4) Good ventilation

Start the crunch....

A well laid chassis will keep noise & hum from bothering our sanity, prolong equipment life & safeguard any user from electrocution.
Hum & noise, a part from destructing for our sanity, they will definitely corrupt the signal we wish to process. The most significant effect of corrupted signal is noticeable loss in micro details, in a bad case, a blur broadcast with a constant hummmmmmmm...
A good electronic circuit is one which will reject unwanted signal while going about their intended purpose...
Weak signals are easily influence/corrupted by unwanted signal. such as RFI, EMI...etc. hence we must keep them away from noisy stuff such as EMI (electromagnetic interference) which are mostly generated by electromagnetic stuff such as electric motors, transformers, chokes, magnets...etc. RFI (Radio frequency interference) are generated by high frequency switches, PWM devices, radio wave transmission, microwave oven, solar burst... etc etc..
We can just shield external noise with a Faraday's cage which is basically putting everything inside a grounded non-magnetic metal chasing such as aluminium casing. Steel casing is ok but it does conduct magnetic thingy (which can be a PITA to debug) within the steel sheet unlike aluminium.
That take cares of the external noise. How about there are those internally generated noises within an amplifier.
General good practices in setting out an amp's interior layout is simply to separate the noisy stuff from the quiet stuff with air space. From my experience, most EMI can be minimised by a clear space of 50~65mm. To do this it is a good practice to make sure all the irons are amply spaced up with their coils perpendicular from each other & away from any signal path. Another good practice is to keep all the dirty & noisy stuff in one end & all the signal path in the furthest corner.The noisy stuff being anything closer to the mains supply & the quiet stuff are those closest to the signal inlet socket.

High current AC stuff induce electromagnetic field around them, disregard of their voltage. Filament wire is one of the know culprit. There are many solution to this, one of which is to employ DC heater supply as DC current induce very little electromagnetic field. That is the main reason for phono amps. DC filament supply can be complex & it has great impact on the sonic, particularly the size of the filter capacitor, it won't filter properly when its too small, & dull/death sound when you overdose... Some of the reader will enjoy tweaking the DC filament circuit but for me it is a PITA.

It is no secret that I personally prefer AC heated tubes; IMHO, it is easier to build a fantastic AC heater filament implementation then to do a lousy DC filament implementation. Most importantly the lively & unstrained sonic energy it radiates.

The simple solution to this is to use twisted filament wire, tug them into chassis corner, & keep them away from signal path. If crossing signal path is unavoidable, cross them perpendicular to each other. Less for more :)

Ground loop

Ground loop is the main culprit to hum... The practical approach of ground loop management is a faculty by itself hence not going to talk much of it. As for this build, I'll just take thing easy & go with the flow....

The Aikido PCB has a good star-ground layout, hence I'll use star ground scheme to manage the ground loop.

Transformers layout

It is necessary to finalise the PSU component selection before going about the irons placement in the chassis.

We need the PSU specs. before we can start & these are the numbers needed:-

Current requirement : 7.2ma x4= 28.8ma call it 30ma for convenient sake.

Voltage requirement : Since Aikido is not picky with B+ value, I'll just use what ever 230Vac, 50Hz can give which should fall anywhere between 300 & 325Vdc

Components I have : 8H @ 164 DCR Choke, 10uf, 68uf, 100uf, 120uf, 150uf, 220uf capacitor all rated at 450Vdc

Get PSUII out & play around with different parameters... Finally satisfy with the following concoction...

from here, supplementing other good design considerations & good DIY practices. An exact scaled 2D dimensioned chassis layout appears.

Well.... that goes another good 10 hours on the project :)

As you can see, when one take all good practices into design considerations, there is no way a tube amp will get anywhere close to the size of 20 iPod stack.

~~.....Part 3 Preview.......~~

Churn out a 3D chassis design base on the 2D plan we had just cooked up...

Aikido Pre-Amp Project - Part 1

2011-09-24T19:33:00.003+08:00

Looking back my DIY audio journey, my objective in every project undertaking is to get to the point where a safe & functional good sounding amp soonest. My effort in aesthetic are limited to point-to-point circuit construction which is beauty to my eye... There is just not enough energy left for aesthetic works....

This time round I'll will emphasise on the aesthetic work...But within reasonable degree of form-follow-function.

Like any projects in life, embarking on a project without laying down the goals is a sin...
Hence, a list of objectives in the order of priority
1) Quality finishing & Aesthetically appealing. Good enough to go on a display shelve.
2) All components must be from my junk pile.
3) Class II electrical safety compliance (double insulated form user)
4) Complete the project within 80 man hours
5) A project even a 12year old can complete.

Now the path is laid, one can start to eat the elephant a bite at a time...

DECISIONS, DECISIONS, DECISIONS...
Designing from scratch is fun but you are committed to a total unknown out come... Hence, this time, one gotta let go for one's ego for the better & use a trial & proven circuit.

Amplifier Design
A quick summary on Aikido. It is created by John Broskie. Requires 4 triode per channel to work, & the common practice is to use dual triode envelope valve, such as 12AX7, ECC88, 6N1P, ECC81, 6SN7... etc etc.
Aikido is such that it is almost immune to whatever tube selection or operating point (within common sense limits of course), it will produce fantastic audio result disregard. The only decision you will have to make is what sort of gain you need & what sort of output impedance you require... Spooky... :) To cut all the theory, I'll just say distortion cancellation is at work in this design...
Also, this amp is death quiet! It also design for power supply ripple cancellation!

I had built a myriad of Aikido pre-amps even using it as the driving stage of my 2A3 SE DHT with various tubes combinations & operation conditions; Construct using point-to-point construction technique, some uses bus bar ground & some using ground plane.

Sonic quality is fantastic, the image actually defy physical boundary & literally extends outside of the room! Neutral, dynamic & great micro-details are really high on the top echelon equipments.

Form of Construction
This is a solid design. Unfortunately, collect all the parts & construction from scratch will eat up the 80 man hour budget... even cutting my own PCB is out of the question...

I bought a few kits in return for John Broskie's generously sharing his work freely. This will be the best time to put them to their intended purpose.

This will be the second kit I build since I took the DIY path, the other kit was my inaugurate tube project which is a 6EW7 Kit from audiohobbyist many winters ago... And you guess right, the 6EW7 didn't survive my relentless hacking & eventually fell into pieces... Hope this Aikido will have better luck...

Tube Choice
6SN7 is the tube of choice, it can yield a gain near 10 &amp & when running this circuit at 300V & 7.2mA per tube we can have a super low Zo of 685ohm; Its perfect for a line stage & even also an great headphone amp!

Power Supply Considerations
The kit has all the bells & whistles but you gotta build your own power supply.
6SN7 will work safely with 250V on the anode & when stacking 2 6SN7 it can safely use 500V B+ but since I have a few isolation transformers lying around, it will by default using B+ of 300~325V. Aikido is designed to have superb PSRR by design, but it helps with a solid & well filtered power supply.
I'll use the following power supply topology which I got repeated good results in the past. It sounds really close to a tube rectifier power supply.

That concludes the first 2 hour of work on this project.

Next 2 hours is to is to get things organised.

Dig up the irons required. Huge 100VA @ 230V isolation transformer for main B+, 8H Choke & a 30VA @ 2x6V toroidal filament transformer.

A quick stock check of the kit.

Never proceed without this very crucial piece stow box!
One must have a large enough stow box for stowing you project between play time...

This is how its used...

This IMHO is the bare minimum size10"x13"x8"deep, & it comes with lid & rollers too :)

No blog is not complete without eye candy

.........PART 2 preview .........

In my next post, I'll spend time on the chassis.

3D Scanner

2011-06-05T20:21:00.000+08:00

As a lazy person, constructing 3D model in CAD is way too tedious, too much work & too slow for me to do joyously... Naturally, I rather spend time check out YouTube...

A digital scanner seems to be the thing for me.

Scanner.... Hmmmm... the 1st image appear in my head is a laser line sweeping top down across an object of interest on a rotating table...

More google review more then a few way to digitise a 3D object...

Contact method, this utilises a mechanical probe of choice to probe the X, Y & Z coordinate in a very fine grid progression... I reckon I can start immediately by installing a probe on my CNC router & probe away... BUT BUT BUT I can immediately relate to how many YouTube movie I will be watching while waiting to scan a human head size object.... Sure no go with this...

Non-contact method, now this is more like it, a laser line sweeping the object of interest...

OK, what do we do with the scanned data??? & how the hell am I gonna get his data????

POINT CLOUD keep showing up everywhere when I google.... What has cloud gotta do with scanning???? Like rain cloud over my head with lightning striking on me...

Nope, I'm still checking this point cloud thingy....

more to come once I made progress.... Don't touch that dial!!!

Waveboard Panel

2010-12-14T19:38:00.000+08:00

This is what I've been busy with lately...

Solid Nyato timber door panel.

What can my CNC do

2010-10-31T20:52:00.001+08:00

Too many times I was asked what my machine can do...
AND... my usual reply
"It can do many things...."
"Cut, carve, engrave, mill, machining anything that is wooden, plastic or soft metal..."
"Only limit by your imaginations..."
These replies just won't satisfy anyone...
So I actually summon enough energy to break out of procrastination to write down a list...

Here goes...

Sign making – wood, plastic, foam, vinyl, and electronic LED signs.
CNC wood projects – pictures, carving, engraving, parts.
Cool projects – science projects, school projects, DIY projects, and club projects.
PCB milling, PCB engraving or PCB routing of circuit boards. PCB drilling and PCB testing.
CNC robot and robotics projects.
Arts and crafts, cut vinyl, paper, wood, plastic, 3D carving and engraving.
Invent – build prototypes for inventing and experimenting.
Education – robotic manufacturing, CNC routing, CNC machining, science models, physics projects, machines, electronics, woodworking, CAD, CAM. (Great for schools.)
Electronics projects – circuit boards, make enclosures, boxes, cases, labels, panels, and parts.
Mechatronics – Electro – mechanical parts.
Mold making for castings
Fiberglass mould
Lithopen
Scroll saw projects – makes parts faster and more accurate.
Homemade gifts and other projects.
Hobby CNC projects of all types, RC projects, and model making.
Robotics projects – build parts or complete machines.
CNC precision parts for demonstrations.
Pattern making, template making, inlays, and on lays.
Rubber stamps.
Loudspeaker cabinet
HIFI chassis, furniture
Acoustic wave penal
Wood clocks.
Wood furniture.
Cabinet making.
Door making.
Digital cutting for soft metals.
Boat building.
Plastic fabrication.
Rapid prototyping.

Arggg.... too tired to continue...

How to Tell Me What You Wanna Cut

2010-09-28T14:39:00.004+08:00

CNC Cutting Service is new to local customer. In almost all cases, guiding the customers to provide information to fulfil his/her needs is a must.

Obviously, saying "YOU DESIGN, I CUT" is not even close to enough information...

Similarly, "I want a cabinet", "I want a chassis", "I want a box" are not specific enough too...

In this article, I will go through what I find helpful to a meaningful transaction.

All I really need is a clear idea of what you are after.

These tips may seem pretty basic but they can save you time, and money.

Send something in writing: Email, or Letter is fine, or just Email an image.

Don't spend to much time on plans to start with, a quick sketch or photo of what you are really after plus if needed a chat on the phone will cover most thing.

It's better to get a rough sketch to us sooner than a fine drawing later.

If you want simple shapes like circles, rectangles, triangles or quadrants, a simple list with radius or diameter and the thickness plus quantities.

In a perfect world we like longer lists on an excel sheet with each dimension in a separate cell. If you don't know what I'm on about ignore this.

prefer sizes in millimeters but if you happier with inches or centimeters please state which. We just need to understand what you want.

If you can send a CAD drawings or vectored files please do.

If possible put all parts, and instructions on a single file.

If your not a CAD person don't worry we can still read Bits of paper, Word Doc's, PDF's, JPGS, Spreadsheets, etc.

Tips to sending CAD files for CNC routing machining

Importing from Apple Mac vectorworks can still cause problems but it is very rare

It's always a good idea to also send a PDF file so we can check against the CAD file, which can sometimes be corrupted when converting to our CAD/CAM software.

Intersecting curves, and lines need to connect.

Lines on top of each other can cause problems.

We can sort these things out but if their are a lot of curves or shapes it can be very time consuming.

Scale should be 1 - 1 full size. Not vital but a good idea.

We machine from files in millimetres so millimetres are preferred.

Polylines with thicknesses should be set to thickness zero.

2D Files

All the parts on a single of CAD file grouped in material, and thicknesses.

If we have 20 or 30 individual files to handle it's harder to get an over view for quoting, and key file can be missed.

Notes, and details on the file are very useful. Files can be loaded on different computers stations, and emails, and note become separated.

Using layers for groove depths board thicknesses different hole sizes an be very useful.

Early version of DXF, and DWG are can be more reliable than the latest version.

When we transfer data via DXF we will use version 13 or 2000 if possible.

We find DWG slightly more stable than DXF.

If you have a 3D model it is always useful for getting an over view.

It can take time to convert a 3D file into a 2D file so send the 2D file as well.

3D Files

We Machine with V-Carve Pro & AutoCad for preparation

We can take most 3D Solid and Surface files.

Mesh files like STL can loose definition when the parts are large.

An indication of the block size is always useful.

Tips for Adobe Illistrator users sending files for CNC Routing.

If you can send the file as PDF as well it can be a great help.

Files can sometimes change when tranfered to other programs. PDF's give us a visual double check.

It's a good idea to put scale reference like a 500mm square with a dimension on the file with free flowing shapes. Some time's the scale will change when changing from Illustrator to CAD.

We can import Adode Illustrator so machining directly from your files is possible.

If you want text machined explode the fonts to turn them in to graphics. If you send text as fonts, and we don't have your font a different one will be substituted, and your elegant font can come out as Helvetica. Again a PDF can give us a quick double check.

Send the your file as an Adobe Illustrator file not as a DXF.

If you use Illustrator to convert to DXF curves can be broken into small steps that take up a lot of space, and lose accuracy.

Examples of files for CNC routing

We like all the information on a single file.

Some times the file becomes separated from the Email.

From starting to writing the CNC machining program takes just a few minutes.

This saves time, helps prevent error's, and keeps setup cost to a minimum.

This example shows material, holes numbers with detail, and a couple of dimensions.

This job was more complex but the principle is the same.

CAD drawing of parts for a 10 metre boardroom table

We grouped the different thicknesses of MDF in to boxes.
The 12mm MDF (bottom left) was used a templates for the veneer.
The narrow strips are templates for the Hardwood edging. (top centre 25mm box)
25mm parts are machined upside down with work top key hole cut outs.
This may seem a bit chaotic

I sincerely hope that the above information is helpful to you like they are useful to me.

Any comments are welcome. Please feel free to comment. Need your comment to horn my communication skill.

Pleas Please Please!

Ciao

How to Vectorised Artwork from Photo & Scanned Images

2010-09-24T16:12:00.001+08:00

CNC work with vector files, eg. file extension such as .svg, .dxf, .dwg, stl, ai....etc etc

Normal digital photo or scanned images are in raster format, eg. file extension such as .jpg, .png, .bmp

There is an easy way to do it using free open source Graphic Editing software call InkScape.

I wanted to produce a video tutorial but I quickly realised there are plenty smarter people with sexier voice & production skill... hence this wonderful video tutorial...

The first 7min 30secs is what I use exactly for my CNC work... Then save the result in .svg or export as .pdf.
*ps, some times, "edge Detection" yield a better result... but there are no fix solution, its really all about trial & error.

#
#
#
This is for color pix

So now you know how to capture vector graphics using Digital camera, Scanner & robbing pix from the net...

Relief Carving

2010-09-24T15:21:00.000+08:00

Put em Togetter

2010-09-21T19:31:00.000+08:00

This is one of the easiest combination of joinery I use.

My vocab is not good enough to describe

Hopefully the pix can say it better.

Do you get it?

Digital Wood Joinery Lesson No.3

2010-09-21T12:44:00.002+08:00

Finger join is another of my favourite. Practical & aesthetically pleasing to my eye.

Picture tells a thousand word... let the pix talk...

##PS,
I would love to post phot of this but I have yet figure out the way to make onject float in mid air...

Digital Wood Joinery Lesson No.2

2010-09-17T16:45:00.002+08:00

The 3D illustration isn't as clear to some readers as I wish they are so here is a 2D figure with a few more varieties of tong & grooves which I like to employ in my designs.

The Magenta vertical blocks are the various varieties of Tong (male) & the bottom horizontal Cyan are the Grooves (female).
the 1st & 2nd on the left is the simplest form which are my favourite.
the the 3rd requires turning the job to cut both sides of the tong hence I rarely use it.
The 4th, 5th & 6th are great when I want to show off how my stuff snaps on perfectly... :D
The grooves are usually half the wood thickness & the narrower tong of the 5th, 6th & 7th are normally half the plank thickness too.
With CNC precision & cut quality, I usually design the tong to fit the grooves exactly, no need for small clearance/allowance for adjustment during assembly like traditional carpenters do.

These Tong & Groove Joints are self-reference, holding themself up when assembled & you don't need set sqare to square them up or clamps to hold them on. A few tander knock will persuase them to mate up nicely.

Digital Wood Joinery Lesson No.1

2010-09-15T19:13:00.000+08:00

Wood joinery is a priced craft.

Traditionally, any carpenter will feel insulted if you say he nail up his work...

Deep inside, I too feel humiliated without implementing some sort of wood joints in my personal projects.

The RED & Blue are simple butt joints... I don't feel proud when I use them....

The Magenta & Cyan are tong & groove some call it tenon & mortise... this is the least I'll have in my personal projects.

Another modern woodworker's must have is PVA glue, commonly called wood glue or white glue. It is a water based glue that will not break before the wood fiber tears... great for indoor use.

A properly glued joint will take all the abuse you can throw at it before the wood itself give way...

SAY NO TO NAILS!

CNC-ed Stools

2010-09-09T18:21:00.004+08:00

Kenneth & Gabriel threaten to boycott me if they don't get a chair to seat on their next visit to my shop... :(

Buying chair for my shop use just isn't me... Too lazy to hand build some chairs... Procrastination sets in when it is a non-paying design job....

There must be plenty of free chair plans available in the net... so started strolling mindlessly across the WWW....

One will find when one seeks.
A nice stool design in the project page of 100kgarages. I like what I saw here and downloaded the free cad files immediately.

Unfortunately, I can't cut it as it was designed for 3/4 in thick Plywood but I only has 18mm thk MDF. Some customisation is require... but hey, having a free download already save me from loosing gallons of brain juice... can't complain over that...

Without further a do, open up the CAD file, changed the slot & finger joint size to suit the 18mm thk MDF I have, It is always a goof practice to double check the actual thickness for both plywood & MDF before working with it as they can very as much as 3mm... A good a verneer caliper reads 17.4mm averageof 5 readings...
To prevent any possible infringment of trademark of the Makers & the Shopbot, I removeg their logo from the stool panels just in case & pop in some simple graphic pattern? The added bonus is reduction in weight :)

Then pop the modified CAD file into my CAM program, do some careful tool bit selection, tool feed rate, put in some tabs & G-code is ready for my Mighty Blue Beast.
Load up the MDF sheet, calibrate the positions, turn on the dust collector & I'm off for an extended coffee break.
The stool parts are completed & ready for assembly when I return...
As usual, everything snap-on perfectly.... ;)

This should make Kenneth & Gabriel happy on their next visit ;)...

EMC2 Revisit

2010-08-29T16:47:00.002+08:00

Had a go at the Mach3 trial version earlier, it is nice package packed with load of goodies but it does has a 500 lines limit, until I pay up US175 for the full version... It was a lot of money to me so I revamp my system to EMC2 the open source program that is free to own & most importantly free to tweak.

Presently, EMC2_2.4.3 release is available & it can run in the latest Ubuntu 10.04 LTS released which can handle dual-core mobo. BUT since my mobo is single core ATOM board & I'm to anxious to get my machine in full operation mode as soon as possible, I stick to the Live Disc which contains EMC2_2.3.4 + Ubuntu 8.04LTS. I'll go for 10.04 & EMC2_2.4.xx when they comes in live disc...

It is great to have EMC2 back in business, the motors sounded happier, smoother & refine.
From the jam packed Mach3 screen, the bare & simplistic EMC2 AXIS screen suddenly feels empty... AND I missed the Auto Z Touch-off feature... Without further a do, I dig into information on Auto Z Touch-off feature in the wide sea of WWW.

Nothing is new under the sun... apparently; Many EMC2 users had their own concoction & I found good information on one of the step-by-step how-to here...
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?ClassicLadderExamples#Single_button_probe_touchoffand here is how this thingy came about.
http://www.cnczone.com/forums/showthread.php?t=62423

They involve pyPVC which is a screen editor to tweak the custom virtual panel & Classicladder which is a ladder program. on top of that one has to be well verse with the MDI_COMMANDS in the Axis HAL & some Python language....

Took over a week to have a creak at the programes without much success... hence, to save time & loosing hair, I put on my copycat hat & shamelessly copied every step to the teeth & after some debugging & troubleshooting, ITS ALIIIIVVVE!!!

While I was at it, I squeeze in the jogging button for convenient operation.

Next will be a HID (Human Interface Device) using a common wireless game pad.... Don't wait up, I'll never know when I'll get there...

Children Study Desk & Chair Set

2010-08-21T16:02:00.000+08:00

Carving, Engraving & Profile Cutting is fun & the product are pleasant to the eye. BUT mostly useless... Very much like having sex...
This doesn't satisfy my natural crave to build something useful...
I've seen many furniture we made with CNC router... but can this really be done without any further human inteference?
It is unevitable that I set out to build a set of functional furniture... eventually... & that "eventually" came sooner then I could anticipated...
The choice of the month is a Children Desk & Chair set. Why Children furniture you may ask... They are no less difficult then any other furniture & they are smaller (that means less material to buy...) period...
Took some serious effort into research of suitable joineries... After over 2 weeks of toying with various design combination in my head... I conjure enough energy to keep myself nailed infront of the computer monitor for 2 full days to come up with the 1st version...

After a not-so-satisfied prototype & some alteration on the original version. This is my final results. A chair that is ergonimically correct, light-weight & assembled (easily) without glue straight out of the machine. AND (most importantly) they look right to my eye too...

"Flat-packe" profile cut

Now... How should I paint this thing...

MACH3 endeavour

2010-08-17T21:40:00.000+08:00

My Ubuntu OS based PC controller for my MechMate died...
After days of hair-pulling troubleshooting hours, the culprit was found to be the fried Thumb Drive I used as the main storage media... Now, that was a surprise... how often you hear of fried USB thumb drives...
The opportunity of an alternative motion control software arises.
From what I learnt, EMC2 & MACH3 are the two dominant controller software used in the CNC hobbyist community. Both has strong & huge community based support forums & free to download user developed plug-ins.
I took on EMC2 in the first place because it is a free software, not just it doesn't cost real money to own, it is also free from constrain when use.
Thanks to a donated Dell P4 machine with a licensed Window 2000, 1.6Ghz, 512Mb Ram, 20GB. & most importantly a LPT port.
I seize the opportunity & downloaded the Mac3 Trial version for the job.
This trial version is as much as the paid version (USD 175..) the only limitations are that it can take up to 500 command lines... & they limit the pulse rate to 25kHz. Still it is enough for trial cut with simple design but insufficient for complex engraving & carving works.
Setting up is a breeze with my prior experience with EMC2 under my belt.
I immediately rig up the much talked about Auto-Zero programme and scavenged a piece of blank PCB from my junk pile as the touch plate, soldered a thick gauge wire to it & connected to the free I/O ports on the breakout board. Down loaded the plug-in & again, everything worked seamlessly. It was a breeze, even monkeys can do it!
I the tried my luck with the Joystick HID setup, but unfortunately, the plug-in don't work in Win2K... #@!$@#~$!
There are lots of handy feature cramped into this package, it can generate G-code for table surfacing, Pocketing, Spiral cutting, Thread cutting... etc etc etc.. Many handy controls were on the screen & the screen is programmable... Learning curve isn't that steep too.
The down side is that the screen is really cramped with many feature that are not required...
My verdict?
If this is the first time for you with this PC based Motion Controlling Thingy... stick to MACH3...Everything you need for a beginner are there! Even those that you don't need... Its a no-brain-er... It even comes with a CAM programme call LazyCam...
BUT if you want more freedom over the program functionality, go for the EMC2 where the screen is Spartan & the user need to custom their own any additional features such as Auto Zero, Auto-Homing... etc which are also available for free download...

For now, (USD175 is still a lot of money for me...) I will spend more play time with this Mach3 Trial program & when I decided to switch back to EMC2, I'll teach my EMC2 all the neat tricks in Mach3...

Another Health Hazard Management - Dust Collector

2010-08-12T17:47:00.001+08:00

Anyone whom ever worked with wood working power tools can tell you how fast & convinient they make, BUT no one ever mentioned the mess it left with the amount of wood dust, saw dust they generate...
Wood dust get into everywhere! That includes every possible crackes, gap, opening in the building... Those which manage to get air bourn will stay air bourne for hours!!!
Not forgetting the demage they can do to our lungs, nostril & any other opening in your body...

I'm a lazy sob, I hate to do cleaning chore... & I don't want to die of lung cancer...
Naturally, I'm reluctant to use my CNC Router....Cleaning the mess is hell!!!

To keep my sanity & healthy lungs, I installed a full fledge 2-Stage Dust Collecting System... which really is nothing more then a glorified industrial grade vacuum cleaner...

I bought this Twin-Bag Single-Stage Dust Collector, I did planned to build this from scratch but again... As I'm a lazy sob especially when the financial benifit did not churn out more the 70% savin...

The white thingy is the fabric filter bag which stop fine dust from entering the shop ambient.

This is the centrifugal fan which acts as the "sucker"

Since the fan impellar & filter bag do worth some money, it will be best to have a buffer to remove most of the saw dust & foreign object from getting to them. The ideal solution (for me) will be a dust cyclone, which is not difficult & expensive to construct but I came accrose this Thien Separator in the internet which is even easier & cheaper to construct.

This is the Thien Separator which were constructed from a 200L barrael which I robbed from a friend & some fitting & CNC cut plywood. This will drop off 80~90% of the saw dust & any heavy foreign object from contact with the fan impeller and fill up the filter bag.

This how they look inside.

Another view of the separator internal organs

This is the fully assembled dust shoe,

it will confirn the saw dust within the effective vacuum suction region. Also capture larger wood chips from flying all over the place. the brush is a door seal brush & the rest of the wooden structure were cut by my CNC router. Everything just snapped on seamlessly.

The original hole around the cutting bit is round but was accidently demaged during test... but it still work beautifully as it is now... (too lazy to make another...)

suction hose attachement.

More pre-assembled pixs.

Then the flexible host.

And the assembled 2-Stage Dust collection system.

Now.... I am fresh out of excuse to delay cleaning up the workshop....

Upgrade Cooling water System for Water Cool Spindle

2010-07-18T19:42:00.003+08:00

My spindle cooling water pump gave up on me!
No, I didn't fry my spindle along with it :)
I was so glad I had the reservoir made out of transparent plastic container! Saw that the water flow was reduced to a trickle when I started up the pump 2 weeks ago...

After some leg work, found a nice submersible pump. It was a love at 1st sight! black aluminium body, stainless steel impeller & shaft, 415V/3 phase, 1/10 horse power (75 watt) , capable of 2m head but didn't indicate the flow rate... & the best part was its has a RM250 price-tag! well within my RM300 budget! I love it so much that I couldn't care less about the flow rate...
I only need 350 ml/min which I recon a lovely pump of this specs will surely achieve.

Another pleasant surprise to find the shop next door carry some heavy-duty PE tanks! So I just got hold of a 16 liter tank, I choose it as it look about right size to keep the pump stable...

More leg work to find some extra 6mm tubing, connector, reducer, 4 core wires, an on-off switch, some screws, washers, pp tubing tape...
Took a nice Sunday morning in cooling rain to tie everything up nicely...

Open up all the necessary opening for mounting the pump, fit the reducer at the outlet,use up some 20m of 6mm pneumatic tubing to go along the cable chain, I like the pneumatic tubing as it has stiff tube wall, it is light weight & the glossy finishing eye-catching... & some fittings to go along...

Tie up the electic cable, switch, got the motor direction correct & ready for a test.

The pump fills up a 1 liter paint can in 2 minutes 45 seconds, so a healthy 363 ml/min. consider the amount of work it has to get through some 30m long tiny 6mm tubing... an improvement over my old aquarium which was 300 ml/min at its best...

Ran the motor with the spindle running for over an hour & everything is cool & nice! This industrial grade outfit will serve me trouble-free for a long time...

Total damage? RM276... yeah... don't believe everything written on the price tag.... LOL

I would conclude this upgrade a complete success!

What next?
I can' really see the water level despite the translucent tank wall, will buy some of car radiator coolant to give a distinct color to it & give better corrosion protection to my pricy spindle. If it still doesn't work, I'll die the coolant with ink :)

CNC Hobbyist Club

2010-07-09T12:26:00.000+08:00

I love to meet new faces, make new friend. Made more than a few friend around the world through participating forums of various kinds.
Since I started this blog, I received a few mails showing interest in CNC hobbyist activity. Hence, inspired the idea of forming a local CNC Hobbyist Group as a platform for like interest individuals to get together over Teh Tarik session, maybe set up a forum, a Facebook Group or something...
Curious to know how many might be interested... & see if the number warrant any action...
You can respond through the posting comment here
or
email to me Tinkeringken at Gmail dot com

Any comment & suggestion are welcome.

Building Amp - the battle plan

2010-06-10T19:34:00.001+08:00

It is always best to plan ahead. No exception in amp building project.

The first thing I look into is the chassis. Chassis can make or break the project.

Dimensions
My choice is, 17in (432mm) wide, 12in (305mm) deep & 4in (100mm) height.
17 inch wide is the commonly accepted "full width" of any Audio/Video home equipment.
12 inches deep is the size I experienced as "just big enough" physically yet not too clumsy visually.
4 inches is the height that is "just-tall-enough" to mount most audio components such as power capacitors & chokes; This I learn through years of experience.

Layout
I like to keep the power transformers to a corner of their own to keep potential electromagnetism headache which it is associated with. In this particular build, the power trans I am using is a bare, its ugly & exposed, no covers or bells, so I for safety & aesthetic reasons, will keep them out of sight by mounting it inside the chassis. is ugly...
Took some time to create a 3D model of my intended chassis, its only partly completed but these which are drawn will be final. Eagle eye readers will notice I have a larger bottom board for mounting the transformer. This is important, transformer is a chunk of metal & it's really heavy... So a strong base is important. Too lazy to put in all the components in the 3D model. I draw a 2D layout instead.

Building Valve Amplifiers

2010-06-03T15:36:00.001+08:00

This is a series of article on the actual work & design consideration when I build valve amplifier.

Tube amplifier is an electronic equipment, so it is natural to neglect the need for the mechanical works involved... you can't get anywhere without planing the mechanical layout of a valve amplifier.

The mechanical works involved are mostly in the chassis.

How about aesthetic appeal?
This is too subjective a subject to discuss, in my humble opinion, If the chassis layout is superb, it will always look good. but one thing for sure, a poor layout always looks ugly.

Chassis Layout
There is enough stuff to write a book on this topic alone but I won't torture the readers with my lousy writing skill... Instead, a summarised criteria.

Rigid Chassis to take the weight of the irons & owner abuse.
Electromagnetic induction, Components must be positioned/spaced correctly in relative to each other to minimise electromagnetic induction, mostly concern the placement of transformer, chokes & valves.
The connecting wires between each components should be as short as possible to minimise chances of hum induce into the signal & excessive voltage drop.
All components must be mounted securely & rigidly as all components are microphonic to some degree, hence any vibration will affect the final acoustical result.
Provide sufficient ventilation to minimise heat build up.

Learning Aid

2010-05-25T19:26:00.000+08:00

Many interested parties approached me with their dream to enlist my CNC service to cut/carve their dream project. The encounter will start with a warm welcoming introduction, all the usual chatter, asking what I can do & bla, bla, bla... all were rosy & cheesy until I ask what exactly they want me to cut.... Most describe their requirements verbally with a lot of confident,
here is a typical example,
"It a circle this big (size it up with his hand), with a section that is curved like this (swivel his hand in a wave form in the air), has a contour to fit this very rare fitting (show me a photo of the fitting) that goes in this bit deep (sign with his thumb & index fingers). There carve some flame over here (again waving his hand in the air). How soon can I have it?"
Me : " Do you have a drawing?"
" No."
" A copy of the fitting?"
" No."
" Do you have the dimension of the circle, the curve, the fitting and the depth, type of material?"
" No, I tot you can do circles, curves & accurate depth? and please don't make me mortgage my house..."
".............."

Not wanting to be negative about this but its really not enough info for me to do anything at all...

I mostly end up encouraging them to do their own drawing to save the drawing & design fee that I will eventually charge them.

As I require vector graphics, it is natural that I narrow my learning towards that...

AutoCad is my personal preference, and INKSCAPE is free...

IMHO, This is the only place you need to be to learn up everthing there is to know about AutoCAD for free.

If Autocad is too expensive or too intimidating, you can use a vector graphic editing package call InkScape, its Open Source A.K.A Free. Free download here

Some good tutorials & instructions Here

Many videos in YouTube on InkScape
This gives an excellent introduction to InkScape

This has all the tutorials that you may need to become a pro.

Hope this helps.

How Boring is Drawing

2010-05-24T17:19:00.001+08:00

You can not get too bored with drawing...

Just visualise this, when we scribble on a piece of paper, the years of foundation training of flying the crayon on the wall during our childhood days kicks in subconsciously & we are free to draw any lines on the piece of paper & hopefully these lines will mean something to anyone other than ourselves...
When we wish to draw stright lines & constructing meaningful shapes on a piece of paper, the hands will grab a ruler or a protractor & our secondary training during primary & secondary school takes over & there we have nice orderly lines on a piece of paper which actually mean something to most people...
For those who took up some form of institutional engineering training or education will learn to draw & read engineering drawings properly & again subconsciously pack in the necessary information onto the piece of papers with lines which we call engineering drawings...
In my early stage of drawing with CAD, life was really frustrating... A simple task of drawing a straight line can turn into disaster... it really happened! I deleted an entire file because I click on something accidently.... dividing a line into a few equal section can take more than half an hour until I learnt that there is a command that I can use to do so with a few clicks on the mouse & all can be accomplished within a second... to draw a line on tangent of 2 circles turn into a full-blown construction drawings taking nearly an hours when a simple typing tan on the keyboard then right-click the circle can do the job...
Once you get more "fluent" conversing in the correct "language", things can get really interesting & fun filling... eg, we can use "offset" command to construct lines & check size of your design on drawing, make complex contours using "polylines" & play with its sub-commands such as L (for Line) & A ( for arc) on the keyboard, then drag the line to accommodate your desired shapes... copying object is a god sent when identical object are needed; Rotating parts in the drawing takes a bit of practice but they are extremely precise; Moving object to desired location/position is a breeze; Resize the drawing can save hundreds of hours of drawing; drawing chamber & fillers are just 2 clicks away;
Best of all, you can redo the drawing till the cow comes home & nothing is loss... I still recall the amount of eraser scrap covered desk after a drawing session during my school days... not forgetting drawings with holes made by excessive erasing with a laser knife on PP paper...

Pre-raquisite Software Skill for operating the BEAST

2010-05-19T14:52:00.001+08:00

Building the CNC Router was a stressful but fulfilling experience. Inflated ego was the direct product of this memorable journey. BUT that is only the starting line of my CNC endeavour. Now that I have a machine at my disposal, I need to learn up how to drive this machine to churn out those beautiful artifact like we seen in the net.

In retrospect, running the machine is easy, but that is only after you actually operate the machine...

I totally over estimated my learning capacity, & underestimated the complexity of the software involvement in running a CNC machine. After over a month of tinkering with running the machine & many software packages, I come to this overly generalised summery.
You need a Drawing to convert to G-code, feed the G-code to the Motion Controller. To cut properly, one need to know the cutting tool characteristics, material properties & some machining procedure knowledge.

Drawings
To make something with or without CNC machines, we need to provide specific specifications of what to do, so coming up with a drawing is the first step.
From my understanding, we can use 2 types of drawing files, namely Raster & Vector.
In raster, examples are bitmap such as jpg, png etc. With this, the cutter will transverse the whole area covered by the file, this is how most 3D cutting is done. With Vector file, the cutter only travels along the path where the cutting is required, saving lots of time. this is how profile cutting & 2.5D are done.

Drawing software
With different cutting strategies different software are used. In vector files, we direct the cutter in straight lines to cut the profile or contours, leaving the other space alone. In raster file, the cutter will transverse every mm of the file... example of raster files are bitmap. & the generally accepted vector file format is .DXF, other formats are SVG, AI, STL... etc etc
I'm fortunate enough to have worked with AutoCad in my junior career life & residue memory helps a lot when relearning. This is my preference for 2D & 3D rendering but there are others such as SolidWorks. You can also use CoralDraw, Win Paint, Adobe Inventor, SketchUp Pro,.... Open source CAD drawing are not quite up to the fee software but I find Blender is a promising, still crude but its getting somewhere.
I also learn that one doesn't need to draw a drawing from scratch everytime, especially when we are dealing with ornamental & art craft... We can "convert" raster files to vector files by tracing bitmap. I downloaded the open source INKSCAPE software which can do many capabilities of fee software such as the Coraldraw & Adobe AI.

G-code
One can write G-code from scratch if they feel they are up to it, BUT I'm too lazy for that... CAMBAM, UCANCAM, SHEETCAM, LAZYCAM... a whole library of CAM software which can translate vector file into G-code. I evenetually ended up with VCarve Pro for 2D & 2.5D works & Cut3D for 3D works..

At the end of the day, depending on requirement, all common or not so common software packages works, the difference are in the learning curve & the ingenuity of the user to utilise the available capabilities of each. Its a compromise of $, time & requirement.

ITS ALIVE!!!!!!

2010-04-03T17:28:00.001+08:00

Virgin cut were commenced on 5:30pm 31st March 2010....

There outcome.......... Speechless....

I'll just let the pix talk...

The 1st complete relief carving....
Will frame this as it is for me to show my grand children...

Now that I'd build the "car" I'll have to learn to drive.

When is The Virgin Cut

2010-03-28T22:37:00.001+08:00

In the beginning, I gave myself an ultimatum to make some wood dust by March 2010, & its only 3 days way...

Without further ado, here is the status.

Installed the cable chain & layout most of the cables

A closer look at the Gantry

The spindle took position.

Spoil-board in place. now it really looks like a mean machine!

Well, getting closer now, hmm.... still need to commission the spindle, build the water cooling system for the spindle, mount the control panel, do the final cable connection, do the Emergency -Stop installation, install the gas spring, mount the Variable Speed Drive, ... and...... that's it... I guess....

My brother had booked the front seat & my neighbors are all enthusiastic to see the blue beast in action, time & money running low, potential customers & business partners asking for samples...... etc etc
...........lets see if I can make the virgin cut happen on 7.pm, Wednesday, 31st March 2010.

Anyone interested to witness this historical moment (at least it is to me ;) ) are most welcome, bring your own drinks if you wish. I would appreciate a bottle of champagne or 2 for the occasion.

Thats all for now, gotta work on double shift to make this happen...

Wish me luck!

Z-Axis Concoction

2010-03-19T21:45:00.000+08:00

You might notice there isn't much mentioned on the Z-axis.

I did my own "design" to cure my needs to have my own signature in this machine.

Using Linear Slide & Rail bar is more expensive, but it does give peace to my mind & fulfill my over-sized ego...

There you have it.
All Axis are assemble (almost)...
The last piece of purchase to get this to machine to work will be the Gas Spring & a 500mm long gear rack.

Control Panel Revisit

2010-03-16T17:30:00.001+08:00

Took some time out from the Mechanical work to work on the Electrical & Electronics Department.

Bought a economical PC chassis to house the Atom board, its really convenient & took less then 30 minutes to get it done. Should had gone this way from day one, real salvation of my sanity.

Re-mounted the BOB with a ribbon cable to the external connector.

Changed the internal hook-up wire to 18AWG wires. I learn the hard way that thin 24AWG wires keeps breaking under its own weight & my itchy fingers didn't help.

Re-position the contractor, Rectifier & capacitor.

Opened a few holes for the cooling fan, main feeder wires, screen stepper cables... etc

2010-03-13T16:51:00.000+08:00

After the rail alignment, progress took a nose dive to near stop. The are 2 reasons (excuses to be exact) I can come out with.
1) I'm near physically exhausted & mentally fatigue from this build, its like taking up 2 extra jobs... and
2) After all that adrenaline rush from the previous tasks such as steel fabrications, rails grinding, alignments...etc really tough nut I'd cracked, the later jobs looked & feel so easy now, so much so that procrastination starts to creep in quietly...
Anyway, looking at the time & dough I'd invested in this baby, I made an effort to muster enough will power to continue with the journey before I add it to my dreadfully long "perpetually unfinished" project list.

Installed the gear rack on the rail.

Made the Y-track hold-down

The Stepper Motor Drive Assembly

And here we have it. Competed Mechanical bits for the X & Y axis.

All that is left are the Z-axis before I proceed with wiring up the controls.

Alignment

2010-03-06T11:00:00.001+08:00

Now that the Chinese New Year celebration is over, & the main machine structure is up. It is time to proceed with the critical rail alignment work.

This is the most dreaded part of the build. Why so? We all know that we can ride smoothly on a bumpy & winding road. It is the same with machine. without a through rail the machine can never travel straight & smoothly.

What is the primary objective ?
1) line the rail as straight as possible. Here, I set out for within 0.1mm which is equivalent of +/-50micron. which is about the diameter of my hair (which I had just measured...)
2) straightness of within 0.2mm along the 4.4m length x-rail & 1.73m y rail
3) parallelism between the 2 x-rail of 0.2mm

Secondary objective?
1) Using the most primitive tools & equipment I can lay my hands on in my tool box.
Tools I used
1) Filler gauge with 0.05mm to 1mm
2) 30 lb fishing line
3) Aluminium shim salvaged from Coke can.
4) Hole punch
5) a few clamps
6) an aviation straight cut snipplet
7) some spanner
8) a 3lb hammer

No rullers, no micrometer, no dial gauge, no vanier calipers...

Can this be done? Oh Yes.
The last time I lay my hands on similar work was like 2 decades ago, after which I get to supervise/instruct others just by pointing my fingers + a bit of shouting when it calls for ;) . While they slough it out in tropical heat, I get to take refuge in nice air-conditioned office sipping coffee. The for another few year, I don't even get close to job like these...

It was tough at the beginning when I got rusty over the years, but like riding a bicycle, everything came back after a little fiddling.

Will post more on details... once I get everything organized...

No Subject

2010-03-04T19:24:00.000+08:00

Can't find anything to post after Chinese New Year celebration. Had a full 15 days off from work, it's been ages since I had a break longer the 3 days.... Get torturous after 5 days...

The monsoon season is over, it is now the time nature turn up the heat dail, ambient temp goes up to 38C in the open & 30C indoors. On top of that humidity hoovers arounf 60~80% & it is really tough to get much work done outside of an air-conditioned environment.

I'm a weak person, I yield easily with the onslaught of heat & hardship...

What is the hoo ha with CNC Router?

2010-02-12T15:05:00.000+08:00

The followings are some of the response O get when ever I mention I'm building my own full fledge CNC Router...

"When was the last time you visit your shrink?"
"Not funny...."
"Can you do that?"

To me, this is the tool to end alcl tools. I can sell my circular saw, my router, my jigsaw.... almost my complete collection of power tools.

Anyway, I would talk more about some of the stuff the CNC can churn up. Picture tells a thousand wors, so here goes

Enough for now, don't want to slow down page up loading...

Your imagination is the limit of this robot.....

MechMate Gantry & Y-Car Assembly

2010-02-07T14:08:00.002+08:00

With the availability of CNC laser cut machine, fabricator's life gets a lot easier then it use to be. BUT that doesn't say one gets a free ride when fitting them accurately.`

Here are the laser cut profiled components. Most of them will be "Lego-ed" & weld into usable Monocoque Y-Car chassis & Box Beam Gantry

Level & alignment is of paramount important in this excercise.

Hence, I build 2 adjustable trestle from C-Channel off cuts.drill & tap M12 holes for attaching adjustable leveler legs.

Setting up the box section beam on the trestle.

Using Spirit level to line them on horizontal plane.

Align the box section beam by measuring the parallel distance. Comparing diagonal distance to ensure they are square to each other.

Clamp down to hold the position.

Rubber mallet for fine movement by tapping them lightly on the correct places without damaging the paint work.

.

When you are ready, spot weld to hold the assembly together & check for distortion.before doing the final welding.

Here are the Gantry & Y-car after welding & a coat of red oxide primer on the weld.

Closser view of the Y-car, The original paint was severy damaged by welding spatters....Shouldn't have painted...

.....Nothing I can't sort out with a coat of paint.

MechMate Table Assembly Works

2010-02-05T22:33:00.001+08:00

From previous post, I shown the fabricated steel parts for the MechMate build in total loose form, all cut, dressed & painted. A friend who visited asked if they are kit supplied? Luckily, the scent of wet paint proved that I did the fabrication works.

This post will show the progress of assembling the "kit".

BTW, the table is good for 1220mm x 2800mm (8'x 12.5') working area.

The welding set

The "precision" measurement equipment I need for aligning the assembly.

Some of the welding were done on this make-shift welding bench. :)

The tube truss fitted & welded

How I fit the leg perfectly square & perpendicular to the main channel rail.

Completed table side frame

Both side frames completed

Aligned the two complete side frames square & parallel to each other

Place the table cross bearer on its appropriate position accurately. Then weld...

Fit & weld the cross pipe & diagonal pipe brace & you have a table.

There you have it, what is left is to get a group of 6 full muscle grown-up to flip this chunk of metal over...

This is only the table, we have gantry, Y-car....

Stay tune ;)

PS,
Is there anyone out there???? Give me a sign...
please do leave your comment & response in the comment lines...

The Kitchen Table Project

2010-02-01T18:39:00.001+08:00

This project is created by designer & creator of of Mechmate, Gerald.

He is the avovacate of testing out the control electronics & software before the mechanical works were carried out.

The goal AFAIK is to
1) find out if the control panel design one put up will actually work before it is installed on the actual CNC machine.
2) force learning the very basic of the motion controller software (EMC2 in this case) by actually putting you hands on it and not just talk.
3) confirm if the hardware are in working condition as early as possible.

He carried out the assembly & testing of the control panel components in the comfort of his kitchen dinning table, hence the name...

There are a few very detail design which he put up in his plan & discussions in the forum, one can just buy the stuff & follow the "map to complete the whole she-bang. BUT being me, I just have to know the what/why/where/when/how or the system.... so.... took the long way around to do this project ... again...

My design based strongly on Gerald's concept with a twist...
All components are different from his original but they work...
Electrical circuit also varied a little... but still resemble his original concept.

This is my concoction

Software
Motion Control Software :- EMC2 2.3.4 release
O/S : Ubuntu 8.04LTS "Hardy Heron"

Hardware
Computer :- Intel D945GCLF Atom with 2M DDR2 Ram, 8Gb Thumdrive as storage, 15" LCD monitor, keyboard, PS2 mouse
Motor Drive : M860 Leadshine Micro stepping driver, 6A max
Stepper Motor : 98HS9801, 450Ncm, 4.1mL/phase, 4A
Stepper motor Transformer :- EI core 540VA, 0-48VAC
Computer Breakout/ interface board : Sinyu 5-Axis Ver. 1
Breakout board Transformer 0-9VAC, 9VA
Magnetic Coil Contactor : 3 phase, 240V, 18A
other electrical components : Push button, Indicator light,
Control Panel Chassis : Powder coated Metal chassis, 500mm (H) x 400mm (W) x 200mm (D)

Took me over 4 months to get the motors running under EMC2 control.

It had been a huge struggle for me from day one of this kitchen table project. Time, money, sweat, draw a few drops of blood, late night..... frustration come & go....

Some how the moment you hear the motors singing a quartet for you for the first time.... Priceless...........

The CNC Electronics & Electrical Department Happening

2010-01-28T18:06:00.002+08:00

I have a confession to make....

I finally did it! I killed ALL the board in my control panel!!! There goes the PMDX-122 breakout board & the Atom MOBO!!! :(

It all happend in that thundering night, wind howling... fist size rain drop pouring.... blue flashing thunder... door banging....... Err.... nothing of that sort, ;p

Over the X'mas holidays, I proceed to wire up the control panel. Individually, the magnetic coil contactor, E-stop circuit worked out the Mobo worked fine, BUT they don't jive with each other, ...

Wire all the components, press the start button, hear that satisfying "thump" made by the magnectic coil contactor, and a few blink of the monitor & everything went black-out.... Dead! Mati! Kong! & I didn't have the pleasure to seeing smoke!!!

With a puntured ego & coffer, I went back to search for another board as the return shipping charges to send the dead BOB back to the maker is plainly irrational.

Undetered by this set back, I (again) dive into the vast ocean of information- the internet & picked up this SINYU 5-Axis Interface Board. from the ebay.

This chunk of populated electronic component PCB features a Manual Jog function by connecting a home made joy pad, the circuit for the joy pad is given in the manual.
It has 2 Relays which I can switch on larger Magnetic coil relays for auxillary equipment.
Charge pump featured
Unique 10-wire ribbon cable terminal for connection to the Stepper Driver. I have a choice to configure the board for 5 stepper driver connection or 4.
4 sets of powered 3-port terminal with 12Vdc VCC ready for home/limit proximity switch connection.
Takes 9Vac as power which is easy to implement.

AND it is $$$ friendly too.

As for the Mobo, a replacement were sorte.

Total damage?
RM836 = USD 245 = EUR175 = GBP151= ZAR1,860 = 11,360 rupee = HKD 1,907........

ooooooooouuuuuuuccccchhhhhhhh........

##PS,
Read the small print

So..... Please support this blog by clicking on the ads.... every cent counts.....

;)

Paint Job

2010-01-24T16:37:00.004+08:00

After some back breaking working with steel, All the steel (at least what I know is requires) are cut, drilled, taped, ground, de-burred and painted.

This is the hardest part of the whole build as I have to lift serious weight, endure flying sparks, deafening power tools noise, work in dust filled environment, work on my knees, squatting for long hours & drinking 3 litter of water each day for over 2 weeks...

My advise, get a helper....

The dust is intensive, I lost count after I swept up two 50 liter buckets of grind steel dust...

I then decided to paint the steel before welding to avoid the intensive Yoga exercise session if I were to paint the table after the table is completely welded... Can always repair the scratches & welding burnt paint with a tat to extra paint...

Painting is a PITA task, easy to do but takes ages to reach a competent level of finishing...

How much PITA? Before you paint, one has to prepare the steel...

Firstly, you have to remove loose scale & rust with grade A60 sand paper or power brush with an angle grinder,
Secondly, you have to rub down the dust & any oil stain from the surface with solvent, I use patrol for this task as they are great solvent that are easily available & they will evaporate without a trace. There are other practices such as wahing the steel with light detergent but I alway prefer how I did it...

Then you get to paint...

Now, you can op for spray painting or hand painting... as my body is all sore after the earlier works, I hate to haul all the steel into the open & haul them back to the workshop after they are done... AND its raining season... a bad bad thing for wet or half dried paint...

*ps, It did rain a few time (per day) during the 3 day span of my paint job.

I use 4" paint roller for the job, some how, I can't paint with normal paint brush & roller saves me from the emberresment. AND with rollers, it is easy to control paint thickness & produce a even matted finishing which I like.

My paint selection :- 1 coat of Red Oxide primer & 2 coat of Enemal Alkyd paint (commonly know as Glossy paint).

More painting PITA....

Apply the 1st primer coat after the patrol had evaporated & squeaky clean...
Wait...... 4~6 hours for the primer to cure enough for the top coat... Too short the curing then the primer will be too wet for the top coat, too long the primer will harden too much for the top coat to "bite" on to the primer coat...
Apply the 1st coat, do not brush over the same spot over & over again, this will make the top coat to mix with the primer coat... Nevermind if you can still see the tint colour of the primer coat on this 1st top coat, you can get this corrected with the 2nd coat.
Wait..... read the instruction on the paint can, it says 4 hour for touch dry & 6~8 hour to re coat.... I waited 8 hours & they still feel too tacky for the second coat so I left them over night to cure properly...
The 2nd coat will be a breeze as you had already 2 coat of practice & finish in no time.

This is what I got

The laser cut profiles.

The table parts including the rails in black

The table bearer channels 1 1/2 x 3" channels

Close up of the main 3" x 8" channel

The table leg & supporting tube trusses

Not forgetting the rails, with 2 coat of smooth black Hammerite paint...

Progress

2010-01-18T19:19:00.000+08:00

The special feature of this MechMate is that one could choose to make their own precision rail guide which are not short in quality in comparison to off the shelf guide rails. With some simple tools, a lot of patient, enduring loud grinding machine noise, & 2 weeks of back breaking work, I eventually completed the rail guides.

The whole lot

A closer view

View from another angle

This is the first milestone of this build & I hope there rest of the build will be less laborous & demanding.

My Steel Fabrication Arsenal

2010-01-09T13:50:00.002+08:00

After much considerations on verious factors, I'd finally decided on work area of 183cm x 380cm (6'x12.5'). To prevent any further change of mind, I went on to buy the steel & started cutting...

Here is my arsenal,
The heavy artillery.
Commonly named Chop Saw, its a 15" Circular Abrasive Disc Cutter.

Others may use continuous band saw or metal cutting circular chop saw for the job, but for my budget, this will work just fine.

Another alternative may be Oxy-Acethylene cutting torch. but the heat will warp the steel which I can't live with.

Plasma cutter is on my wish-list of all cutting tools... They are just way out of my budget limit... :(

Light Artillery,
4" Angle Grinder.
for touch up job & light deburring.

Steel stock scatted all over the shop floor.
Some 3"x8" C Channels, for the X-axis carriage beam
1 1/2" x 3" C Channel for the Legs & cross bearer.
Dia.50mm Black "C" pipe for table trusses
Dia 25mm Black "C" pipe for trusses
T-bar to be cut & grind into X & Y axis rails.
50mm x 100mm x 3mm thk Rectangle Cross Section for the Gantry Beams.
and Flat bars as drill guide then salvage as clamping strip for the Gantry.

Steel Cut to size, at least for now...

Drilling job,

Drill & tapped for mounting the X-axis Angle Rail onto the main Channel Beam.

Close up of the finished tapped the holes,

The M8x1.25 Spiral bit I used to tap the holes

This is only part of the work done so far, I would say 80% of all steel cutting, more to come... I believe in the 80/20 theory, initial 80% of the job is done with 20% of effort, and the 20% of the remaining job requires 80% of the effort.

The next order will be tough, cutting & grinding the Angle Rail.... Stay in tune!

More Franzy

2009-12-24T19:53:00.002+08:00

Its a long holiday weekend ahead and I'm so happy playing in my little sanctuary.

Is for my bench drill & bench belt grinder, 5ft long 2 ft wide. Completely out of 15mm sheet plywood.

Its lightweight but extremely rigid.

Why? Because I can

Free plan is available upon request.

(As I don't know how to host one for download.... :( but if someone could teach me... )

The bench in commission...
I has envisage a much tidy & organised working area... but I don't quite get that result... This call for more furniture???

Dust Making Franzy

2009-12-24T13:58:00.000+08:00

With a newly constructed sturdy as a rock 8 ft long workbench, there is no way I'll rest my tools... Anyway, I "do" really need some storage & shelving in my little sanctuary, Any excuse is better then non... I'll started with a book case.

Its soooooooo comfortable.... NO BACK ACHE,

Hmm.... doesn't feel right, I think 4 feet spend is too far for the shelves... & a bit too wobbly as well

Have no fear, help is always is at hand. Nothing a 15x45mm wood to reinforce the shelves & more plywood as shear reinforcement in the cavity.

Here we are... Do I need finishing as she will always be in the store room under the stairs.

............... maybe a coat of shellac later.... aaaaa....loooot.... laaaaterrr....

What next... another bench for my drilling machine & bench sander????

Workbench

2009-12-19T20:08:00.000+08:00

Got tired of using makeshift table & boxes...

Now that I have an empty shop to tinker, I must build a custom workbench.

Free plan of the bench is available upon request.

The stuff that makes up a PSU

2009-12-19T18:11:00.007+08:00

In the previous post, I choose a E-I Core, 300VA, Secondary winding 48Vac. which should have 66.5Vdc 4.5A

I happened to have a 540VA, Double bobbin, 36Vac E-I core tranny collecting dust in my junk box. It says 36V, 15A, So I approach a friend to add a few more coils on the secondary and I now I have a 48Vac, 11.25A tranny for the job.

Now for the Capacitor,

Voltage rating,
It is safe to have a 1.5x safety factor over the expected rated peak,
So, 66.5 x 1.5 = 99.75V
so a 100V rating Cap will do just fine.

Another safe formular to guide us along,
C = (80,000 * IMax. total) / Vdc (microFarad)
C= 80,000*(4*4)/66.5 = 19,248.12 uF

Capacitors don't come in this exact size
This is what I found off the shelve, a 22,000uf, 100Vdc Screw terminal electrolytic capacitor.

Ractifier is easy,
minimum Voltage rating is 100V, minimum current rating is 4x4x1.5=24Amp but we know from the tranny selection 2/3 of that would be enough so 2/3 of 24 is 16Amp

I got this KBPS2504,250V & 25A. metal casing which is good for heat dissipation. when I mount it to any metal plate.

Next, is Wire selection, We know the motor rating is 4A max, but nominal operating current will be much less. Anyway, 14 gauge AWG wires will do 4amp nicely & since they are easy to get I used some 8Awg (easily 15Amp) speaker cables for the job. all I need now is some crimping pins, some soldering work....

A quick wiring work yielded this

Value Engineering the Stepper Motor PSU

2009-12-07T19:39:00.001+08:00

The word "DESIGN" had been over rated & over used... Everyone in the advertisement design something... I prefer to use "SELECTION". e.g. select a few different color clothing & you have a in-store fashion designer... do you "design" a 200hp engine for your car or you select? Do you select chopstick over fork & Knife or design... Can anyone claim the credit of designing a wheel? but we keep seeing this " we design of the wheel to xxxx, yyyy......."

Enough of my ranting, lets get back to the Stepper motor Selection.

Like everything else, we must know what we need before we can conduct a proper selection.

Stepper motor system consist of a stepper motor and a Stepper motor driver or amplifier.

Stepper motors takes in high current pulses which the motor driver made by chopping a DC current with respect to the instruction from the Brain. So we need to prepare a DC power supply for the Stepper motor system.

We starts with the Voltage rating,,

There is a straight forward & safe formular commonly used in the industry,
V=32 x SQRT(Coil Inductance in mH)
you can go higher but just watch out for the motor temperature.

EG,
My coil is 3.5mH
Vdc=60V

Secondary Voltage of the Transformer
Vsec=(60V+1.4V(voltage loss of rectifier))/sqrt(2)=43.4V
common transformer off the shelf are, 6V, 9V, 12V, 24V, 36V, 48V.
So, 48V is my choice. this will give
48xsqrt(2) -1.4=66Vdc#

Current rating
Most will follow the convensional wisedom and add up all the max.current rating of the motors & call that the PSU's current rating.... Nothing wrong when its a small system with total 6 Amp of current, but with a full size machine, the motor max rating of each motor can be 7~8 Amps... if there are 4 motors, the DC is 50V, that will require a 1400VA~1600VA about 2hp!!! That will be huge, heavy & expensive!

One must understand that we normally don't use up all the power the motor can do, i.e. the rated power... the motor will only produce "enough" power to move whatever they we designed to do, so it is all too common to see motor rated for 3kw only work 0.5kw with plenty of headroom.

With that in mind, lets do some "value engineering",
We know
we will never run the motor to the max limit because its a bad design practice. we know all the motors don't run at the same time...
Now we need to determine how much current the motor need to move the burden it was entrusted with. again there are more then one way to find the number,
By mathematics model, culculate the weight, inertia, moment... etc of the overall mechanism & find out the torque and hence the power required... I always keep this option last... even if I can, why should I go throught the whole trouble?
By experiment, build the machine, measure the torque required, this is always a good option, but I need to build the machine first....
Empirically, we can measure the current drawn by motors in similar machines.

I went for the empirical method, many reported to run on 300VA without risk of over heating and burning transformers, Even though they have a different voltage rating from mine, 300VA is the figure I need to know.

VA is a very close equivalent to Watt, VA is derive from multiplying the Voltage and the Current, this current is the resultant current and the current of W is the reactance current, but they are very close in number in this case.

Regulated or unregulated Power supply,
Again, common wisdom will pick regulated power supply, but really it is the worst choice for this application.

The nature of the stepper motor operation is such, when stop, they draw near zero current and when they move, they need current immediately or risk loosing steps,

Regulators are not famous for fast response, to ensure they meet the motor demand, they have to have the full power ready all the time, but the machines hardly use up the the max as we know by now, that extra power will turn into heat and wasted...

As for Unregulated power supply, they only give when the load ask and it does have a capacitor to act as a ripple filter & double as a reservoir.

SO since SMPS is normally regulated & the unregulated one are not good in drastic load demand, it is ruled out.

Transformers
There are few types of transformer core, The C-core, R-core, Toroidal & E-I core.
C-core & R-core are not as commonly available as the used to be and that leaves us with Toroidal and E-I core.
Toroidal Core is a more efficient transformer, but it is its efficiency that became its weakness in this application.
Toroidal response to suddent load demand extremely well, so well that it will burn itself when responding.
E-I core is less efficient magnetically, but because of this deficiency, the hesitation acts as a buffer to protectects the transformers from burning its coil.

So, there you have it,
My best package selection is
Transformer :- 300VA E-I core transformer with a 48Vac secondary voltage
Rectifier :- Bridge rectifier with metal casing, rated over 100V & 25 amp
Capacitor :- 22,000uf @ 100V Capacitor based power supply.

This also turn out to be the cheapest & the least technological advance combination.

Why The Stepper Motor

2009-12-07T18:12:00.000+08:00

We have to look back to the type of control system that we select.

Two main types of control system, Open-Loop & Close-Loop.
Open-Loop control:-
The Brain send an instruction to the Muscle and expect the instruction to be carried out perfectly. and never bother to go back to check if the job had benn done properly as told.
Close-Loop Control:-
Commonly named Servo-System. The Brain will send instruction to the Muscle, after completing the instruction, by using encoders the Brain will cross check if its been done correctly, if there is error, the brain will instruct the muscle to make the correction/adjustmet, & repeat the cross-checking until the brain feels happy.

Another advantage of a Servo system is they can move much faster then steppers.

The first reaction for most will be to use an close-loop system, error correction, faster speed... simply because that is how a healthy person will think. BUT after a quick search, one will learn that a close loop system will cost an arm & leg.... Not willing to hurt the pocket & further complexity, one normally settles for Open-Loop System...

Anyway, most CNC router employ a stepper system as their muscle and they had been proven competent mostly.

A compromise must be made, Generally,

One must not skim on specification of the motor, such as power & torque.
Eliminate or minimise backlash in the system.
One must tune the machine to ensure the motor doesn't

loose step, i.e. motor turn but the machine doesn't move. The cause are generally asking the motor to perform acceration which the motor torque are not sufficient to achieve, mechanical friction, Load of machine too heavy.. etc.
Backlash, this is the term to describe the "free-play" between the to & fro motion, one can introduce mechanical solution to minimise the error or use software to compensate.
Electronic inteference, one must ensure the instruction signals are transmitted uncorupted by external noise such as EMI, RFI... etc.

There are no free lunch! Stepper motors system is generally a fraction of the Servo-system, so more brain-juice & body sweat is required to compansate the situation. BTW, servo system do have their unique sets of headache to tackle... but that is another story for another article...

When looking at the Stepper motor specs sheet these are the things to look

number of phase, the modern steppers are normally hybrid 2-phase.
number of wires,

4 wires means 2-coils,
6 wires means 2-coils with choice of Bipolar in series or uni-polar (half coils)
8 wires means 4 coils with choice of Bipolar inseries, Half coils or parallel half coils.

Coil inductance of each coil. Lc
Torque.
Max. Current rating of each coil.

Stepper motor normally runs over 10 times the rated Voltage, so the voltage rating isn't important. To find the actual motor Voltage rating, here is a simplified and safe estimate.

Stepper motor rated DC voltage = 32 x sqareroot(Lc)
where, LC is in mH.

Actually, if the motor doesn't heat up too much, one can go for higher Voltage.

Don't ask me why as the answer will come in a few pages or tech ladden write-up which I am too lazy to do.

Generally,

Higher the V, we can get higher speed from the motor, if high speed is a necessary, seek out ahigh coil inductance motor.
Higher the A, we can get higher torque from the motor, check out the coil rating.
The limiting factor is always the heat during operation, IMHO it is always desirable to have as low a Coil Resistance no matter what...
Sufficient Torque, too little can't do the job, but too much doesn't always better. just be rational.

I/O ??? LPPT#1 ??? Parallel Port??

2009-12-05T16:31:00.001+08:00

Lets talk about how the PC communicate with the muscle.

In natural language, The PC is the brain and the stepper motor system is the muscle.

In this specific case, the Intel D945GCLF mobo, is the PC talk to the CNC machine?

To simplify the analogy, lets leave the EMC2 software system, the mechanical structure, mechanism, electrical ...etc out for the moment.

The PC, has a choice to send and receive signals via serial port, USB and parallel port. with EMC2, the choice is the parallel port.

Traditionally, the parallel port is used as the printer port, there are 25 pins which are arranged as per the table attched, can do 8 bi-directional ports, 4 output ports and 5 input ports.

The simplest way to connect the machine & the parallel port is directly via a cable. BUT because the signal strength from the parallel port is not strong, interfering noise can have its way with the signal & the corrupted signal my be of no meaningful use. or if the receiving end is passive or require some "drive" to work properly.
since my Stepper Motot Driver/Amplifier requires about 15mA to function properly, Hence, a buffer stage is used, normally this is made into a separate PCB which are called Break-Out Board or BOB.
I use a PMDX-122 board which I was mislead into buying. You can find plenty of board at half or less price with equivalent of better specifications. Or maybe DIY one for yourself for less the USD10.

The Atom Mobo is Alive!

2009-11-18T20:10:00.005+08:00

The motion constrol system requires a PC to work.... obvious isn't it...

For EMC2, we can use Pentium 4 with 512Mb or more. I had a free P3 donated. but it Ubuntu didn't like it... An used P4 of the correct spec will set me back ~RM400, It is the most economical choice but I have a soft spot for the Intel Atom chip...

Purchased a D945GLF box. Its contained mobo + the N240 processor at RM215. I need to have a ATX PSU, a 2Mb DDRII RAM, and use salvaged LCD monitor, keyboard mouse, HDD, CD drive.

Plug in all the necessary connectors, slot in the RAM, power up... then all hell broke loose for the next 3 day trying to figure out what went wrong.... after swapping a new DDRII RAM, IDE cable, BIOS battery, keyboard, mouse, CD drive and even another HDD. Eventually, it was concluded that the mobo is faulty and while waiting for replacement, (warranty claim), I got hold of the Dual core Atom board D945GLF2 as they only have this in stock...

Back to me workbench, slot in the RAM, plug in all neccessary connector, set the bios, insert the EMC live-CD & we have this

Ran the latency Test, 15,801ns max jitter is just what I hope for.

Here is the screenshot (literally) of EMC2

Lessons learnt? Yes, Murphy Law never fails!!! ....

Apart from that, check your PSU pinout!!!

The D945GLF requires 2x10 +2x2 power connectors.

The D945GLF2 requires 2x12 + 2x2 power connectors

Getting the right PSU at the right price burnt up 2~3weeks of my time....

So you are warned.

Featuring EMC2

2009-11-12T16:44:00.002+08:00

While settling back in my home town, I found time to evaluate the CNC Controller bits.

After pain staking search and review; I end up PC based CNC software controller
1) Mach3 which runs on Window
2) EMC2 on Linux OS

As I wish to have the flexibility to have the last say on the hardware specifications

I eventually ended with EMC2 which is free open source program. Not that I'm cheap, Mach3 is affordable ~USD100, & you can have a trial version for unlimited period for free, it has all the bell and whistles that any top rank controller programs would have. Moreover, help forums and supporting community are strong too.

It is the believed that Open source Linux OS is practically immune to hackers & deathly viruses which I fear most.

About the software

EMC (the Enhanced Machine Control) is a software system for computer control of machine tools such as milling machines and lathes.
EMC is free software with open source code. Current versions of EMC are entirely licensed under the GNU General Public License and Lesser GNU General Public License (GPL and LGPL)
EMC provides:

a graphical user interface (actually several interfaces to chose from)
an interpreter for "G-code" (the RS-274 machine tool programming language)
a realtime motion planning system with look-ahead
operation of low-level machine electronics such as sensors and motor drives
an easy to use "breadboard" layer for quickly creating a unique configuration for your machine
a software PLC programmable with ladder diagrams
easy installation with .deb packages or a Live-CD

It does not provide drawing (CAD - Computer Aided Design) or G-code generation from the drawing (CAM - Computer Automated Manufacturing) functions.

It can simultaneously move up to 9 axes and supports a variety of interfaces.
The control can operate true servos (analog or PWM) with the feedback loop closed by the EMC software at the computer, or open loop with "step-servos" or stepper motors.
Motion control features include: cutter radius and length compensation, path deviation limited to a specified tolerance, lathe threading, synchronized axis motion, adaptive feedrate, operator feed override, and constant velocity control.
Support for non-Cartesian motion systems is provided via custom kinematics modules. Available architectures include hexapods (Stewart platforms and similar concepts) and systems with rotary joints to provide motion such as PUMA or SCARA robots.
EMC runs on Linux using real time extensions. Support currently exists for version 2.4 and 2.6 Linux kernels with real time extensions applied by RT-Linux or RTAI patches.

EMC2 is precompiled with Ubuntu 8.04 LTS (long term support) versions for ease of installation and longevity.

EMC2 has a few GUIS, Namely, AXIS, TkEmc, HALUI. They even has a Ladder Logic program call CLASSICLADDER. For now, I'll concentrate mainly on AXIS which is an ongoing development.

Screen shoots

Balik Kampung

2009-09-10T21:10:00.000+08:00

Its been nearly a decade since I arrived in Sandakan; Now, it is my time to balik kampung.

I'd withness the transformation from a quiet town with empty road after 7pm to traffic congestion till 10.30pm. From RM1.50 plate of economic mixed rice c/w free chinese tea at the wet market to today's RM4.50++ bowl of kon-lau-man at any kopitiam & you have to pay for you sky juice. The resurrection effort of the old town center.

This is a town which will grow on you; With sparse population, vast space with abundance of fresh clean air are there for your taking; Spoiled by the wealth of natural resources this state possess, one don't need to live a stressful life here.

Slowly but surely, this place had transformed from a timber cowbow town to a small oil palm city, with tourism industry creeping in unannounced.

I'm going to miss the stress-free lifestyle & fantastic seafood Sandakan had indulged me lavishly. Most of all, the sincere and friendly locals that tool me in as a part of their community.

Group Buy, Group Build

2009-08-29T20:51:00.000+08:00

The picture of a group of like interest stranges from all age group and all walks of life going after the common goal intrigues me.

I promised myself to jump on any group buy and group build activities regardless.

After years of waiting & fantasizing, nothing ever happened.... @#$%@#

Inspired by the big slogan from spam letter
"One's life is in one's hand",
"You are your own man",
"Be the lord of your life",
"Opportunities are for those who created them"

I took on the task to organize a group buy for ClonAc 2.5.

My friend said " You are a brave man..."

Well, I'm just a the very early stage of this activities and I already had a taste of the things to come...

Followings are some of the "intelligent" questions I get from PM that came along,
"Why don't you do xxx or yyy?"
hey, if you think xxx or yyy is better, why don't you organise one?

"What do you think of xxx, yyy ?"
hey, get appropriate answers from appropriate forum....

"I prefer MMM, wish you luck.... "
I'm only interested if you are interested in my group buy, I couldn't care less about your MMM.

"I would rather buy QQQ & ZZZ"
Go buy la... you don't need my approval!!!

"So expensive! Can't you do any cheaper?"
If its cheap, I would have just buy them myself and do whatever I like at my leisure. I do group buy for the quantity discount, if you join we get better discount la...

"I don't know if I can trust you"
Ya... right... As if you are the only one facing risk... As if it is easy for me to trust you.... do you know if you decided to withdraw from the group buy, I have to fork out money to pay for your promise....

Well, there are many good appropriate suggestions & questions too, which I took very close to my heart, thousand thanks!
"Make sure the supplier is a reputable one, some do disappear after receiving payments"
"Don't over look the packaging & handling cost"
"Don't promise anything that you are not sure of"
"Careful with potential pre-mature withdrawal"
"Final quote will be higher then initial estimations"

There are reasonable request too
"I'm near you, can I borrow your place & tools?"
"Could you teach me how to solder?"
"I know nuts about all this, could you guide me along the way?"

I said "Why not!" to these requests

ClonAc R2.5 or is it ProAc Response 2.5 Clone

2009-08-28T11:56:00.000+08:00

Always like to build my own audio equipments. Give me a sense of self reliance.

There are so much snake oil stories about HiFi stuff...

No matter how much denial, in my humble opinion, Hifi equipments are trendy stuff, during a certain period, everyone rush to high power SS, another time, flea power Single Ended Triode amp... etc etc...

Recent hot press is fullrange driver which denounce the existence of the olde trusty passive crossover...

Why something which everyone accepted for the last couple of decades and stable forte of super high-end loudspeakers suddenly gets this type of negative treatment...Is this due to lack of crossover design know-how (just like the case of nfb)? The proof of the pudding is in the eating. So, I gave myself a great excuse to embark on a pair of well documented famous ProAc Response 2.5 Clone build.

I have to make clear that I design & built many Single Full Range drivers when I first started playing with loudspeakers for a couple of years, but that is because I know nothing about passive cross over and single drivers makes my learning manageable.

The choice are enormous, but I quickly set my eye on the ClonAc for its strong following and involved Dr. Troels Gavensen with 6 versions of crossovers to play and learn from.

My experience with cabinet building, box tuning along with the well documented clone will eliminate all the hassle in this aspect. Moreover, when I do some maths sanity check on the design, they really look like good text book example.

I can concentrate on experiment and learning the crossover without destractions from other elements. It's time to move on from 1 way to 2 ways loudspeakers....

The only draw back is the cost. All drivers are Scan-Speaks, commonly used in High End/price loudspeakers.

When there is will, there is a way.

To achieve lowest capital outlay & generate interest in this shrinking local DIY activity. I took the plunge to organise a Group buy and Group build in Diyparadise forum & Lowyat forum. There are response, interest are plenty but the price held many back.

Lets see how it goes...

CNC Rules!

2009-08-16T20:53:00.000+08:00

To general public, CNC is synonymous to precision accuracy. This had been engraving, so when ever CNC is mentioned, a picture perfect scenario of flawless component of any kind will pop out in thin air... Snap beutifully and flawless in anyway...
"This will redudant the engineers, technician and operators..." Some say,
"Just tell the machine and you will have all sorted out perfectly... " the other follows
Like instant noodle, not many actually pay attention to the process of making instant noodle "instant". Overtime, misconclude that it only takes 2 minus to make a bowl of soup noodle... sad isn't it...
Try throwing a piece of raw material to the CNC machine and say, "machine this into a ball for me", and see what will happen.... Exactly, nothing will happen.
CNC machine of any kind is another piece of machinery that requires human to opera, not just any human, but skill machinist.
The strenth of CNC machine is that they can provide consistancy, machine consistancy. But they couldn't care less if what they are doing are correct or safe. they wouldn't bother if the cutting tool will break with the size of cut, they wouldn't care how the finishing with turn out... all this require careful programming by skill engineers, technician or machinists.
So, be warned,

PC Based Controller

2009-08-08T01:17:00.000+08:00

The recent phenomenon in hobbyist CNC boom could have been contribute by the progress made in PC based controller software. The flexibility offered by the software and minimal computing power, open up the gateway for hobbyist into the once secluded CNC arena.

There are host of controller software available, some are free, the most popular is the Linux based EMC2. Some are pseudo-free... i.e. trial download with unlimited period, with some function limited. Such as Mach3.

Presently, I'm torn between the GNU free licience Unbuto V8.03 based EMC2 & Window XP based Mach3. I don't believe good things can come free but the Linux family is exception. The Mach3 is affortable at US$150 a pop once you are done with the free trial version.

Since I can't decide which is the clear winner, I'll have a creak at both.

Decisions, Decisions, Decisions

2009-08-06T19:34:00.000+08:00

Decision is the pre-requisition of any action.

How to come to a decision?

Information, knowledge and experience are the basis, with good analytical sense, assimilate oneself into the subjective circumstances, we can make an appropriate decision for the situation.

In my humble opinion, there are no right or wrong decision. It is how appropriate a decision is.

Why MechMate?

Lets look at various aspect of the design to simplify the analysis.

1) Linear Transmission,
This employs rack and pinion,

Leadscrew/ball screw to operate in the length involved will face undesireable swirl into oscilation, rack & pinion does not suffer this naturally.
Cost effective then ballscrews.
More rigid then Belt & pulley
More precise then Gear & sprocket.

b) V-groove wheel on angle guide

Cost effective the linear bearing on rod guide and linear slide on precision square fuide.
Lower resistance and friction then bush or metal to metal bed.
Sufficient rigidity
Sufficient accuracy
Easy to implement

c) Monocoque Y-Gantry & Z-Car Body

Light weight
High rigidity
Running gantry over x and y-axis is most foot print efficient

d) Stepper Motor + Micro-stepping Driver

It is cheaper to set up an open loop motion control then close loop servo motor system.
Microstepping improve smoothness of transverse motion.
Accuracy is well within requirement

e) Well developed PC Based Controller.

f) All material and mechanical parts can be source locally.

f) I already has the tools required to construct one.

g) Plenty of scrounge opportunity to fits the machine to my wallet.

h) My research shows that this design is so well thought through.

i) I don't think I can find or design one that is as good as this

j) The is a free plan by enthusiast, very professionally done, more detail then many paid plans that I'd came across over the years.

DIY CNC Router

2009-08-04T18:32:00.000+08:00

There are many approach to own a CNC machine, you can buy one of those industrial CNC machine center or you can build one with recycling printer stepper motors, some bearings and guides.... For me, I'll skip the baby toys and jump straight to building a Mechmate; A full fledged real McCoy CNC router. Like this one here.

This beautiful design is the work of Gerald. D, he generously give away his design for free and will provide selfless support from his forum. Thumbs up to Gerald.

Why not design myself? Surely I can, if I spend the next 10 years on it... And since this thing isn't going to be cheap to build, I might as well take the "safe" path and get it to work as-soon-as-possible.

I will build one that can take in a full size 4' x 8' sheet. wood based material such as plywood, MDF, chipboard.. etc. Soft metal such as aluminum, bronze, copper. Plastics such as Teflon, Darline, acrylic, prospect, polycarbonate... etc

My Spec.
working size : 2440mm x 1220 (8' by 4')
Tool head : 2.2kw Water Cooled Inverter Controlled High Speed Spindle head.
Drive Motor : NEMA 34 stepper motor
Motion Control : PC based
Precision : +/- 0.01mm

Had been spending like no tomorrow for the past month and the spending never stops....

I am scheduled to start construction by end September or early October....

Wise me luck...

Re-Tinker CNC

2009-07-25T19:41:00.000+08:00

A quick Google and we have more then a few pages on home build CNC machines of all sort...

There are 4 major components that make up a CNC machine
1) The tool head
2) The linear motion
3) The Motor drive
4) The controller

The tool head is what one decide to use the machine to achieve, be it lathe, milling, punching, grinding... etc. The criteria has not changed much since the industrial revolution and I do not foresee much changes in the near future. The new comers are water jet, plasma cutter, laser cutting, EDM or even 3D printing. These had revolutionized how many things are done and I will expect more to come.

Linear motion used to mean linear motion in X, Y and Z axis, but today, it does include rotational movements around the axis, which are called "DoF" Degree of Freedom. The design considerations involves size & material of work piece, speed, accuracy required, finishing requirements. is how the tool and work piece move with respect to each other.
Fix toolhead with moving work piece? Fixed workpiece with moving tool head? or move both partially?
Tranmission & motion conversion from rotation to linear motion,use mechanism such as lead screw & nut, belt & gear, rack & pinion, gear on chain...
Rail guides to ensure transverse in straight line using linear bearing on rod guide, roller on rail... etc

No drastic changes from what I learn in my school days...
I think I'm still pretty up-to-date in this area.

The greatest different were the controller and the motor driver development and availability.

The drive system, for stepper system, it consist of the stepper motor and driver; for the servo system, it consist of the servo motor, encoder and the motor driver.

Today, micro-stepping driver are available at an affortable price, I think this is the main reason for the CNC boom in recent year. Well within hobbyist pocket size.

Servo system too has become much more affortable, but still has room to go.

Only a few years ago, 'serious' CNC machine are built with a customized controller console with its own computing capacity and PC based controllers are in their infancy.

The controller takes in G-code, A.K.A. command list and send control signal to the driver which consequently operate the stepper motor.

What is G-Code? Its a code that the controller take in for processing and the code normally starts with 'G'. Serious... eg, G 00 means stop, G 19 is move to... etc

There are software that convert .dxf files from most CAD programs to G-code, or one can write the G-code manually. I'm still looking into such programs presently.

Currently, there are many affordable, pseudo-free & free PC based controller software, they all have active supporting forums, the two that cough my attention are Mach3 and EMC2.

Mach3 is a window based controller software, it is free until you decide to "go commercial" with it. USD150 will buy you a pop.

EMC2 is a Linux based open-source controller software under GNU license. This thing runs real time kernal, all the bells and whistle and more...

I think I've reach my typing limit for the day... blurry vision...tired finger joints...

How I Got Myself Into This Mess

2009-07-25T17:16:00.000+08:00

Lately, I'm feeling the effect of aging working against... Soldering differed due blurry vision, workshop progress halted as my back ache...

Without much to do, I stared at the monitor and decided to retrace how I get myself into this mess.

I started in metalworking,
I learn welding and machining in my polytechnics days.
Woodworking is a hobby.
Electrical came naturally.
Fabrication is a big part of my day job.
My engineering skill grew through work and play...
Self-thought practical electronics to fill in the blank.
Analytical skill & experience are symbiotic...

Discounting those dismembering alarm clock events and bicycle repairs, the first "serious" machine I built was in my polytechnics days.

Its a stepper motor driven X-Y table carrying a high speed spindle. We build the X-Y table with Acme-lead screw and linear-bearing running on surface hardened guide rails.

My part in the project is the Linear Motion portion of the project, i.e. X-Y table, the motor & the spindle. The challenges were to design and build a light and rigid X-Y table which carries a high speed spindle, this table will transverse accurately to the stepper motor rotation.

The designing was easy, we were given the required leadscrew pitch, x and y treavels, estimated loads and the desired tolerance/accuracy. Throw all these info in salad bowl and came out with a set of CAD drawings of the "ingenious" design. Even tried to model a finite element analysis but not complete due to time constrain.

As ball-screw was expensive then as now, we opt for to machine ACME screws in the workshop & the Anti-Backlash nut and holding blocks while were at it.

After gathering all the part, shower after shower of welding spatter and flying grinding sparks, we got everything assembled. The hardest part was to align and tune the finished assembly. I can still remember how much easily metal flex under load and the agony of getting everything line-up precisely... Till this day, I'm still puzzled how we pulled off the project in such short time... Nevertheless, that was great fun and my inauguration into machine building.

Maybe I should re-kinder with CNC machine for old time sake...

Tools

2009-07-25T16:23:00.000+08:00

Tinkle and tools hoarding are symbiotic...,The more I tinkle, the complexity grew... Need for more tools... Or was it the other way round?

Ah.... those polished-shiny-blinking tools...
The growing tool collection and the size of my junk box are the physical evidence of my tinkering journey... or is it my impulsive shopping habit...

The tool collection growth irrespective of the current global economic outlook... When time is good, you buy cos you have the moola; When time is bad, you buy because you have plenty of time to play....

What's New?

2009-07-09T13:27:00.000+08:00

I made a quick listening to the 6DJ8 preamp. As most tube amp that I build, she sounded good. but not great. Usual tube sound characteristics are present. Clean, crisp, sexy mid range... I should further tinker with the component values to tune for "optimum" result but there are so much distraction in this materialistic world...

My new toy had arrived...

Dress in Red,
Miniature,
Slim
Comes with bottoms...
And Spikes....
Just the type I like...

Impossible to keep my hands away...

Downloaded the open source Arduino environment here

Plug in the USB port

Set the Dip switches

Load the scrip

Press the biggest keyboard key

and

Blink! Blink!! Blink!!!

I herein solemnly declare I'm Micro-Processor Enabled!!!!

Wah Ha HA HAAA!!!

These Came with the kit,

All the bells and whistle

That Says.....

More to come!!!!!

Completing the Schematic

2009-06-06T15:56:00.000+08:00

Now, lets finish off this before my new toy arrives.

Lets organize all the numbers that we had determined.

input is assume to be 1Vrms so Vp=1.414V

#additional note, normally, we will try to bias the tube at least 0.5V away from 0V grid, to prevent grid current, but in this case, the gasin of the stage is so high that before we even get close to 1V of the 0V grid, the power stage should have over loaded. so it doesn't matter.

DC state
B+=300V
Vp=90V
Vbias=1.3V
Ip=15mA

RL=14kR 3W
Rk=86R 1W
Rg=1MR 1/4W

PS resistor = 2 x 200R 5W
PS Reservoir cap = 22uF
1st stage Filter cap = 68uf
2nd Stage Filter cap = 68uf

Arduino

2009-06-05T23:51:00.000+08:00

It has been a few years since I’d started to look for a mean to start on micro controllers stuff. PIC is the recommended chips as I was told they are cheap and abondon locally.

Bought many books and spent hundreds of hours surfing the net with no fruitful progress…. These books eventually became my best cure for insomnia… It never fail to put me to sleep in 20 minutes…

Everything which I found require me to build some thing, either a programmer or hardware to actually make the micro chip work… Its too much challenge for me… so the search continue

Found this book while wondering aimlessly in my local book store a month ago.

By Massimo Banzi, co-founder of the Arduino Project. Published by Make Magazine.

The cover cough my eye.

“Arduino” has appeared with increase frequency in my google search for how-to starter packages for electronically challenged beginner like me. I didn’t dig this AVR based board as I was looking for PIC stuff. What a mistake!

This is the only book on MCU which I finish reading in one go… and awake!

I learn what Physical Computing meant, Arduino uses C language, everything is open source, the board contain the necessary hardware to operate and plugin USB.

Arduino is “ready-to-go”, no need to know about bootloading, I/O connections, I2C, USB chip, communication chip... etc etc which I couldn't care less, so that noobies like me can get our claws right into the fun part.

There is a growing community such as
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl
Seriously fun ppl.

and their web page is packed with great stuff such as ready made codes/programs, meaning we don't have to reinvent the wheel!
http://www.arduino.cc

The potential application is only limited by your imagination! We can do useless thing with it such as teaching our flower to call for help when they get thirsty, lights off in the absent of occupant, control an autonomous robot, intelligent home system, track the sun, control an miniature UAV, feed the monkey, skin the fish.... all of which you can jump straight in as long as you know what make things tick, perfect toy for tinkerers.

Just placed an ordered a "clone" Arduido starter pack, (wanted to go for the real thing but they have the best shipping charges.) should arrive by next week, can't wait to blink some LED....

The Basic Circuit

2009-06-05T23:20:00.000+08:00

I was forced to learn up Eagle to produce this circuit.

Tube Curves is Your Friend

2009-06-02T14:31:00.000+08:00

Common stereotype misconceptions that tube design is for tube gurus with in-depth tube knowledge, Master Yoda-ish character and is one-with-the-force; In reality, anyone who is competent in prevent/avoid electrocution while working with high voltage and still remembers Ohm’s Law is competent enough. All you need is the data sheet. Allow me to demonstrate.

Firstly we get hold of the 6DJ8 data sheet as follows:-

You can start by determine the max and min safe work condition, gain, Rp, rp, plotting the best loadline… etc.

BUT I WON'T!! I will reserve that for your self-amusement during your dreary hours…

Use the Data Sheets recommendations and get straight to it before the irrational impulse of building a tube preamp subsides.

From the #Page 1 of the Data Sheet we have
Filament voltage, Vf = 6.3V,
Filament Current, If = 365mA
From this, we calculate the power required by th filament Pf = Vf x If = 2.3W

#Now write down this on your shopping list, “ 6V, >2x365mA (1A is common),transformer”

At the end of #page 2, "maximum rating, absolute value"
Series grid Resistor = 1 megohm max

you will find "Typical Charateristics" and the followings

Plate Voltage, Vp = 90V, This is the voltage across the anode and cathode
negative grid voltage, Vg = 1.3V, this is be the Bias Voltage
Plate Current, Ip = 15mA, with triode, Ip= Ik, cathode current

Now some maths,

Find Rk, using Ohm's Law,

V=IR
R=V/I
Rk = Vbias/Ik = 1.3/0.015 =87 ohm #

Determine B+,
We will use Isolation Transformer, In my part of the world, main power is 230V AC,
Using Isolation Transformer with a bridge will yield,

Raw B+= Sqrt(2) x 230 = 325V,
we will filter raw B+ to 300V

VLoad = 300V - Vp - Vbias = 300V - 90V - 1.3V = 208.7V #

RLoad = VLoad/Ip = 208.7V/15mA = 13,913 ohm we can choose 15K resistor.

Well after all this hard work, I need to get my regular coffee fix.... We'll continue on the next installment

How to Sound Like Tube Guru 101

2009-06-02T13:59:00.000+08:00

How to Sound Like Tube Guru 101

Common Cathode CC is name as such because its Cathode is connected to the Common Ground.

The CC is good at Voltage amplification, i.e., magnify signal; this is generally the strength of glassware.

It has high input impedance of easily a few hundred thousand ohms; in plain English, it is very sensitive to input signals and very easy to drive.

Fairly high output impedance, which means it is not so good at driving difficult or less sensitive loads such as Solid State Amplifiers and Loudspeakers without some neat tricks but its sufficient to drive another tube stage.

Biasing, to get the tube into operating condition, we set the DC bias or quasient state, its like getting your car on idle speed; When AC signal (yes, signal can only be AC, that includes noise signal too) is applied, its like stepping on the accelerator, and the engine will respond accordingly to how hard you step on it

There are 2 biasing methods in general, Fixed-Bias and Self-Biasing. My emphasis will be on Self Biasing as IMHO they are easier to tinker with and better sounding too.

Self Biasing means we put something (resistor, LED, Diode, Battery or Constant Current Sink) between the tube’s cathode and the ground so that it can generate the required bias voltage by themselves, hence Self Biasing.

Input signal, lets consider CD player output signal of 1Vrms, that means 2.83V peak to peak. V max of +/-1.414V.

You don’t need an input capacitor solder in your circuit as CDP already has an output cap to do the job.

Output coupling. We are going to use Capacitor coupling. This capacitor will ensure only signal voltage is delivered to the next stage. That’s all you have to know for now.

Recite the above to your pal is enough to impress your tube ignorant buddies.

Common Cathode Amplifier

2009-06-02T13:10:00.000+08:00

Common Cathode Amplifier

Glass-tech is over a century old…. How hard can it be????

To cut short the chase, we will pay exclusively attention to triode for now. This should spare us from pages upon pages of boring tech-loaded content. Jumping straight to Common Cathode Amplifier (CC from here on), will speed up the whole process even further.

There are more then ample articles written on the basis theory in the net, spend some effort to google will reap fruitful return. I'll leave this to the readers to decide.

CC has its strength and weaknesses, but hey, it constitute vast majority of audio circuit in its plain or modified form, that speaks strength for itself.

Tinker with Tube Circuit

2009-06-02T12:56:00.000+08:00

To begin with, my motive was learning electronics. I wasn’t looking for that illusive “Tube Sound”, as I was neither an audiophile nor interested in Hi-Fi. As the matter of fact, I don't even know what "tube Sound" meant!!

Fortunately, from my day job, I learn enough electrical safety practices to avoid electrocution. Nevertheless, it is an act of plain stupidity to take on 230V D.C. without paying due respect lethal aspect of electricity.

With help from very patient and persistent and unselfish cyberspace friends from all corners of the globe, I made leap and fold progress. Friendship sprout rapidly among like interest people. Its like I’d found my second childhood that I never had, it has been a fulfilling journey.

Today, through the journey, I'd beginning to have the ear for good sound and developed my own preference. I do my best to go for the best possible sound at least to my ears when designing and building amplifiers. It feels satisfying.

Tinkering 6DJ8

2009-05-28T19:19:00.000+08:00

6DJ8 is the tube of choice, small signal triode, with 2 triode encased in one glass envelope.

It has a large family which is fully compatible, namely,6922, 6N1P,6N11, ECC88, EC88C, E88CC, E188CC, E288CC, .

Plenty of tube rolling opportunity.

It is good sounding, wide applications. It's high Gm, medium gain and low Plate Resistance. With some circuit tinkering, we can build quality Pre-amp, Buffer-amp, driver for small power SE amp, headphone amp... etc

IMHO the only tube which will sound normal when connected as cascode.

There are plenty of NOS (New Old Stock) available, as well as current production.

Tube Tinkering

2009-05-27T17:39:00.000+08:00

Toobs!

Quote
"In electronics, a vacuum tube, electron tube (in North America), thermionic valve, or valve (elsewhere, especially in Britain) is a device used to amplify, switch, otherwise modify, or create an electrical signal by controlling the movement of electrons in a low-pressure space."

Wikipedia

A century old tech, their place in this modern world are limited to large scale signal transmission thank to its robust operation capability.

They some how managed to survive the guitar amp industry due to various aesthetic and nostalgic sentiments.

Mythologized by modern marketeers with hypes limited only by imagination. This glass ware is gaining support in the HiFi consumer market as well.

We get increasing impression of tube amps being more art then technology... IMHO, when we don't know the actual science behind a technology, it is most convenient to save face by branding them as art....

Despite all my negative impression on the sales slogans, I truly love the "Tube Sound", its as close to paradise as one could get.

In the coming articles, I'll share my tinkering journey with 6DJ8. I'll talk about some theory and specification stuff but I do my best to spare tinkerers with heavy doze of boring theory stuff instead just outline the essential start tinkering with tubes.

Circuit Theory for Tinkerers

2009-05-27T16:01:00.001+08:00

Like it or not, we need some basic Circuit Theory for tinkering in electrical and electronics gadgets.

BTW, changing a plug, replacing a wire, spay some paint does not count as tinkering in my book. When I tinker, I dig deep.

Where did I picked up the circuit theory know-how?

All Engineers took electrical classes somewhere along the academic route; We enter the classroom, went through the motion of listening to the teach/lecturer, collect all the handouts, do some tutorials and off we go to the exams… to return the knowledge in written form. Hopefully, some of these knowledge will residual in our brain. In my case, Ohms Law, power and summation of component value calculation stayed….

Lucky me, enough for tinkering and be dangerous.

Ohms Law

V = I · R

V is for voltage, V is the unitI
I is for current Ampere, A is the unit
R is for Resistance, Ω ohm us the unit.

From here, we can derive the following equations

I = V / R

R= V / I

Power

P = V · I

Where,
P for Power or Watt, W is the unit
V for Voltage across the component
I for current running through the component

Summation of Resistance

Series Connected Resistor,

R_total in series = R₁ + R₂ + R₃ + … + R_n

Where,
R_total is the resulted total Resistance of the series connected resistors
R₁, R₂….Rn are the Resistance of individual resistor

~handy tips,

When connecting same value resistor in series,

Use This --> R_total = R_individual x Pieces of resistors

Parallel connected Resistor,

R_total = ((R₁)^-1 + (R₂)^-1 + (R₃)^-1 + …. + (R_n)^-1)^-1

Where,

R_total is the resulted total Resistance of the connected resistors

R₁, R₂….Rn are the Resistance of individual resistor

~handy tips

When connecting identical value Resistor in parrallell

R_total = R₁/ pieces of resistor

How to use them?

Ohm’s Law enable us to figure out how much voltage is across the component and how much current going through the component.

We use this as the minimum required ratings, i.e. current, voltage and watt rating of the components. *PS* For Power rating, give it at least a double,I triple when I have the chance.

Summation of resistor allow us to add/reduce R_total in the circuit. By changing the R_total, when use with Ohm’s Law, we can figure out how to adjust the current and voltage of the circuit and/or components. Which is an essential know-how for tinkering.

Computers and Micro Processing Unit

2009-05-25T21:57:00.000+08:00

My inaugurate experience with computer was the Sinclair ZX81, a present from my aunt during my primary school days.

It displays a green screen on home TV. It was also the first time I actually learn something by reading instruction manual. Manged to write simple BASIC language program to occupy the screen with numbers and alphabets, make them blink, change color and make some beeping tone... etc all the usual big hoo haa at that time. I was never successful is saving any programs on tape recorder as described.... Also we can play Pong with it.

At the end, I annihilated it in the search for higher wisdom.

My next "serious" encounter with computer was in my polytechnics days when the syllabus requires CAD drawing on a Prme Medusa system, FORTRAN77 and 8051 mcu programing. The 8051 is a populated PCB baord and a 2 x 7 segment display and a input keypad which we used to punch in HEX machine code. We happilye blink some LED, excitedly make the Knight Rider running light and a traffic light as course work. Frankly, I didn't learn anything from here as my attention was on those sweet young thing around.

I then used WordPerfect in the uni's computer lab to write my final year project, the great graphics features and lovely spell check made my life much more bearable.

Then came the windows, the internet, Netscape, IE, the dot com bubble... and I was happily going along with the flow.

Until a few years ago, a fellow audio diyer built a NOS (Non-OverSampling) DAC with 3 DAC chips, namely the TDA 1541, 1543, 1545. He used a mcu to control relays for selection of chips for AB test. Another made source selection with mcu controllered relays. This sparks some interest.

For the pass 4 years, I'd been trying to start tinkering with mcu but some how it didn't happened. Firstly, I don't know where to start, and when I did, I don't have a programmer, then then training kit was too expensive and I'm too lazy to built one, one hurdle after another.... consequently, a netural death...

Why I Tinker?

2009-05-22T16:26:00.000+08:00

I am cursed with impulsive curiosity toward the how's and why's of "things" works, just couldn't help it. Tinkering with things is how one learn the working principle of things and deal with my incurable decease.

To deal with this curse, I dig and strip anything that fancy my curiosity. Eventually, I'll build a similar "thingy" base with some variance as proof of concept. One thing lead to another, I end up a hobbyist carpenter + machine machinist + metal worker + electronic technician and whatever is required of me to make it happen.

For the past few years, I embarked on electronics "thingy" because I am really an electronic idiot. DIY audio equipments seem to be the right track to teach myself electronics... again, one thing led to another, I design and built more then a few tube amplifiers and loudspeakers.

This blog will be my platform to share my learning experience with the like mind people and hopefully will start a few friendship along the way.

Maybe someday... after I'd satisfied my appetite for electronics, I'll proceed with shipwright... who knows... For sure its a bigger money pit.

Until then lets do some soldering, hole drilling and metal cutting.