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...
Saturday, July 25, 2009
How I Got Myself Into This Mess
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...
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
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....
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....
Thursday, July 9, 2009
What's New?
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!!!!!
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!!!!!
Saturday, June 6, 2009
Completing the Schematic
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
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
Friday, June 5, 2009
Arduino
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....
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....
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