[Coco] George's CNC Machine (WAS: Something else)

[Ron Bihler]

The speed all depends on how fast you want it to interpret the moves and how 
accurate you need this to be.  Trade off, accuracy requires more math and 
processor time hence slower movements.

Most programs are taking the circle movement and breaking it into small line 
segments. Again depending on how accurate you need.

I am also running a sherline mill system, I am using an old Fijitsu tablet 
pc.  Granted it is a Pentium, but turbocnc is doing all the work of handling 
the stepper motors.
The Par port is connected to stepper controller, step and direction is all 
controlled and it moves faster than I would have expected considering how 
slow the system really is.  I suspect this is still 10 fold faster than a 
coco, but then again without all the messydos overhead one can never tell.
This system is pretty accurate, good within .001" or better for circle 
movements.

I also have an old American Robots Robot.  6-axis movement, this was running 
on a 68k system.  Once the system would boot (Close to 10 minutes) it was 
very good.  But that's a 68k system, required to perform reverse kinetics 
movements.  Major math here.  I upgraded for a Pentium II system, night and 
day difference.  Bottom line, the coco should be able to do some basic 
circle interpolation, but it will not be the fastest system on the block :)

I also used an vintage Emco lathe system, no idea what processor they used. 
It was dedicated to the task and was plenty fast.  But considering I was 
only able to transfer the code at 2400 baud with character spacing it must 
have been a slow processor.  1984 vintage.  The point was this system did 
work very well with a much slower processor.

I am assuming he is not needing .0001" accuracy here, doable but not fast. 
This also makes the assumption the coco is doing all the work, with JRKerr 
modules they just receive some simple serial commands and control the 
steppers or servo drives.  In this case the coco should be able to do much 
of the work and pass the true movements onto another processor.

I am not involved with JRKerr in anyway, but I sure have used there products 
to automate several task within my shop.  I own a scientific glassblowing 
company, I can't find good help anymore and have had to resort to automating 
many of the task. Honestly I do have some good help, but they hate 
repetition and can't repeat like automation.

Sounds like a very interesting project, thanks to Chuck I may include a 6809 
system into some of my operations.  Sure is easier to program than the 
messydos systems. I can understand what's going on, and it doesn't need 2gb 
of memory to operate.

Ron
Author RiBBS

----- Original Message ----- 
From: "Gene Heskett" <gene.heskett at verizon.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Tuesday, September 23, 2008 9:29 PM
Subject: Re: [Coco] George's CNC Machine (WAS: Something else)


> I'm not Ron B., but I do have a small amount of cnc experience, running 
> emc on
> a linux box to run a Harbor Freight MicroMill that has been heavily 
> modified.
> emc can run up to 9 axis's, and I'm currently running 4 myself.  The
> processing power required to do that math in real time needs a faster 
> machine
> than the coco, but it can do it nicely on an old xp-1400 athlon, drawing
> characters on the workpiece at speeds in the 10 inches a minute range, at 
> any
> angle, to sub-micron accuracy if the mechanics are that good.  Mine 
> aren't,
> but can usually stay under a thou for error.
>
>>
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>
> -- 
> Cheers, Gene
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
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