DIY CNC Machine How Hard Can It Be?

[D from BC]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

D from BC

 

[Tim Wescott]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I would go wit USB or serial. Parallel would be a pain, serial is not
well supported by new PCs but is fairly well supported by USB devices.
USB would be best, and you can get single-chip USB interfaces, but you're
left with the responsibility for a Windows driver, even if all you're
doing is using someone else's.

I don't know anything about motor controllers.. Are their dedicated
IC's.?

Yes, for all sorts of motors.

Is this a tricky area?

Yes, but you can learn it. Find out the differences between stepper,
brushed DC, and brushless DC motors. I'd probably look at brushless DC
motors, but if you want to roll your own driver life can get complicated.

Hopefully I can power everything using cheapo computer power supplies.

D from BC

Hopefully. If not, MPJA has generic switchers for not too much more.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

[martin griffith]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

D from BC

Have a look at this
http://www.jraco.com/pdf/hctl1100.pdf
which may give you an idea of how it may have been done in the old
days.
I've only used motion control on video camera rigs and rostrum cameras
( as an operator), so this may not be the best approach for CNC.


martin

 

[D from BC]

I would go wit USB or serial. Parallel would be a pain, serial is not
well supported by new PCs but is fairly well supported by USB devices.
USB would be best, and you can get single-chip USB interfaces, but you're
left with the responsibility for a Windows driver, even if all you're
doing is using someone else's.

Yes, for all sorts of motors.


Yes, but you can learn it. Find out the differences between stepper,
brushed DC, and brushless DC motors. I'd probably look at brushless DC
motors, but if you want to roll your own driver life can get complicated.

Hopefully. If not, MPJA has generic switchers for not too much more.

Cool... piece of cake

Laser tables can sell for about $30000 CAD.
I can probably make a crude CNC machine for maybe $2000.00 (including
35Watt laser) using new and scrap parts and 6 months of my spare time.

I might do some practice first with some inkjet printer stepper
motors..
Heck..I might be able to use 80% of the parts to make a mini CNC for
practice before making a monster 8ft x 5ft table.

Anybody know if someone converted an inkjet printer into a CNC?
D from BC

 

[Ecnerwal]

I'm tempted to design a CNC machine for a laser.

Try alt.machines.cnc and www.cnczone.com

It's a fairly common sort of temptation, and there's a good deal of
experience available. Some aspects depend on things like need for speed
(it's one thing to do something overnight, another to crank it out in 5
minutes) and another is how much you want to do the whole software end
of it yourself, .vs. using someone else's software to save time on the
"getting it functional" end. Yet another aspect is how big - things
differ when you want to CNC with a 4 inch work area, .vs. 4 feet or 40
feet.

 

[martin griffith]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

D from BC

found this on teh internets
http://www.jrkerr.com/pscmc.html


martin

 

[D from BC]

Have a look at this
http://www.jraco.com/pdf/hctl1100.pdf
which may give you an idea of how it may have been done in the old
days.
I've only used motion control on video camera rigs and rostrum cameras
( as an operator), so this may not be the best approach for CNC.


martin

I noticed the 1999 copyright..That's like 400years ago in techno time.

So I looked over the motion control IC..Interesting..
It didn't take me long to see the learning curve .. arrrgh..
D from BC

 

[D from BC]

found this on teh internets
http://www.jrkerr.com/pscmc.html


martin

Heyy...that GUI looks familiar..
I think I saw some guy on Youtube.com use it for his homemade CNC
machine.
D from BC

 

[D from BC]

Try alt.machines.cnc and www.cnczone.com

It's a fairly common sort of temptation, and there's a good deal of
experience available. Some aspects depend on things like need for speed
(it's one thing to do something overnight, another to crank it out in 5
minutes) and another is how much you want to do the whole software end
of it yourself, .vs. using someone else's software to save time on the
"getting it functional" end. Yet another aspect is how big - things
differ when you want to CNC with a 4 inch work area, .vs. 4 feet or 40
feet.

I'll make an effort to search for time savers...hopefully without
taking too much time.

I'll check out alt.machines.cnc...
My first post there could be
"How Do I Build a CNC?" .

Too much?
D from BC

 

[[email protected]]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

D from BC

At one time it was obvious. DOS, LPT, motor drivers, stepper motors.
Write your own Breshenham routines and HPGL converters and have
control over each and every step. Most of the cost was in the ball
screws and mechanicals.
With windows and USB, machine controlling is very difficult and most
of the work has to be outsourced to bought in custom processors,
controllers and software. Essentially you now have to rely on the
skills of others whilst relegated to being just a consumer with deep
pockets.

 

[D from BC]

At one time it was obvious. DOS, LPT, motor drivers, stepper motors.
Write your own Breshenham routines and HPGL converters and have
control over each and every step. Most of the cost was in the ball
screws and mechanicals.
With windows and USB, machine controlling is very difficult and most
of the work has to be outsourced to bought in custom processors,
controllers and software. Essentially you now have to rely on the
skills of others whilst relegated to being just a consumer with deep
pockets.

I sometimes program with Delphi and thought maybe I could just do all
the processing on my PC and somehow spit out the positioning data via
USB to the motor controllers.

But ...it's never that easy
D from BC

 

[linnix]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

Power supply would be the least of your concerns.

D from BC

If you build them, we will take a couple (may be more).

Requirements:
1. Drill/Cut through 0.6 mm silicon wafers (150mm or 200mm).
2. Positioning within 0.01 mm.

Part suggestions:
MC33486 - Dual High Side Bridge Driver
STM32F103 - 32 bits ARM M3 uC w/ USB

 

[D from BC]

Power supply would be the least of your concerns.


If you build them, we will take a couple (may be more).

Requirements:
1. Drill/Cut through 0.6 mm silicon wafers (150mm or 200mm).
2. Positioning within 0.01 mm.

Part suggestions:
MC33486 - Dual High Side Bridge Driver
STM32F103 - 32 bits ARM M3 uC w/ USB

Well..if I keep at it..maybe by 2009..
My mechanics design is not as good as my electronics design..

10micron positioning...mmm
Hows this for an idea..
A laser reads the pits off an optical strip to check for XY position.
The optical strip is similar to the material used for DVDR's.
But I don't know the pit to pit distance for DVDR's.

D from BC

 

[colin]

Well..if I keep at it..maybe by 2009..
My mechanics design is not as good as my electronics design..

10micron positioning...mmm
Hows this for an idea..
A laser reads the pits off an optical strip to check for XY position.
The optical strip is similar to the material used for DVDR's.
But I don't know the pit to pit distance for DVDR's.

D from BC

rs232 is so easy to do, so many micros have it too,
theres always usb to rs232 converters if you pc doesnt have one.

you can get very high resolution optical incremental encoders,
if you want to roll your own you with a sloted disc and quadraturte opto,
you could always use a micro's on board ADC and work out the position
between slots.

you can get many motor driver chips wich accept logic input,
microcontroller development boards are quite cheap on ebay.

big question is how to arrange the table slides and dirves,
theres lots of options, linear round shafts,
toothed flat linear guides etc,
toothed belt drive, screw drive ..
or you could have it polar type with rotating rather than sliding parts.

You can also get x/y slides to fit onto pilar drils to turn them into
milling machines,
just add motor drive/position sensing.

I hope your doing this for fun rather than to get something realy good at a
low price.

Colin =^.^=

 

[BobG]

========================================
There are a couple threads on avrfreaks.net from microcontroller users
that have built CNC machines for making pc boards.. they talk about
their favorite Gecko controllers and motors etc.

 

[linnix]

Well..if I keep at it..maybe by 2009..

We need them sooner, but there are always outsourcings.

My mechanics design is not as good as my electronics design..

You just need enough reduction gears to step down the motors.

10micron positioning...mmm

Up to 50 microns (0.05mm) might be OK.

Hows this for an idea..
A laser reads the pits off an optical strip to check for XY position.
The optical strip is similar to the material used for DVDR's.
But I don't know the pit to pit distance for DVDR's.

There will be existing patterns on the wafer to fine tune the
position. You can turn it on with fractional power, check the
position, then full power. A camera chip would be enough to read the
positions.

 

[Mark Zenier]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

Folks in the Seattle Robotics Society have done a whole bunch of stuff
like this. Dan Mauch is one name I remember from Nuts&Volts magazine
articles. Look to see if this stuff is up on the web, or in one of
the web archives.

Mark Zenier [email protected]
Googleproofaddress(account:mzenier provider:eskimo domain:com)

 

[joseph2k]

I'm tempted to design a CNC machine for a laser.

For electronics I need:
PC interface
motor controller
and power supplies.

I don't know which interface to pick ...USB, serial or parallel for
the PC interface to the motor controller.

I don't know anything about motor controllers..
Are their dedicated IC's.?
Is this a tricky area?

Hopefully I can power everything using cheapo computer power supplies.

D from BC

Before reading any other replies: None of these interfaces support decent
real time processing. CNC machining is a true real time situation. The
power supply question is nearly irrelevant. Now where did that Ad for that
fast CNC machine go to? Oh, just google fast CNC machines. Once you see
what they can do you may get some clue as to what is required to build one
from scratch.

 

[joseph2k]

I'll make an effort to search for time savers...hopefully without
taking too much time.

I'll check out alt.machines.cnc...
My first post there could be
"How Do I Build a CNC?" .

Too much?
D from BC

The fundamental basic of USENET news is to read a few hundred posts (or a
weeks worth) before posting. Google has consistently dismissed this as
well as most other cannonical properties of USENET news. For a few years
now they have treated us to lamers that think this is a bulleten board
system (BBS), listserv, chat room or blog. Do you know what any of these
are, or why they are different?

 

[joseph2k]

Well..if I keep at it..maybe by 2009..
My mechanics design is not as good as my electronics design..

10micron positioning...mmm
Hows this for an idea..
A laser reads the pits off an optical strip to check for XY position.
The optical strip is similar to the material used for DVDR's.
But I don't know the pit to pit distance for DVDR's.

D from BC

Oh defacation, how clueless can you be? Just buy pre-encoded strips. They
are intended to be mounted on low TCE measurement reference bars. Then
again they may no longer be generally available.