Saturday, August 29, 2009

Group Buy, Group Build

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

Friday, August 28, 2009

ClonAc R2.5 or is it ProAc Response 2.5 Clone

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...

Sunday, August 16, 2009

CNC Rules!

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,

Saturday, August 8, 2009

PC Based Controller

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.

Thursday, August 6, 2009

Decisions, Decisions, Decisions

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.

Tuesday, August 4, 2009

DIY CNC Router

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...