[comp.graphics] Laser Cutter info

ddulmage@cdp.UUCP (12/16/90)

Hello. I'm posting this here as I have had a lot of email requests
for this info, and some of it has not reached the people that have
asked for it.

>I am interested in whatever you can tell me about your laser
>plotter system. 

Hello. My laser cutter is built around a Techno "AutoCad Replicator".
It is built very similiar to the large linear translation stages
that you would get from Klinger, etc. for optical applications.
My table has a working area of about 10x15 inchs although they are
available up to about 4x4 ft. It is run from a small card cage that
holds its own cpu and stepper drivers. The system is programmed over
a serial port by very simple ascii commands. There is software 
available that can translate dif. plotter motion descriptions into
these ascii strings. In place of the z axis on the mill, I have a 
sheet of 1/4 alum. that serves as a bed for the piece that I am
working. Mounted next to the table is a small <20 watt CO2 laser.
The laser is manu. by Synrad. It is VERY compact (would fit in a
brief case!) and runs off of 110v or even 28vdc. It is water cooled
and/or air cooled. Water cooling is just a dribble (about a quart a
minute). The laser can be directly modulated via a TTL input. This
is a PWM type modulation to control power.
The laser is mounted to a rail, at the end of which is a 90 deg.
turning mirror and a focussing stage with a lens. This lens then
sits above a corner of the work piece at what would be your plot
origin 0,0.
I had to write a small basic (eeeww) prg. to format and filter
my Acad plot file data as to accomodate the switching of the
laser instead of a pen lift. I then just send it out thru a
teminal pgm. to the mill. This had to do with fact that because
I do not have a z axis on the mill, its cpu would take that
axis out of the final move and refused to ack. an internal ttl
line that I wanted to use to sw. the laser. If I would have
included the z axis stepper driver (but not the actual stage)
the cpu would take care of this line automatically.
The whole system cost under $9000.00 to build. Its been very
reliable, and has an amazing amount of torque (had to back it
down before I lost a finger or something.) Oh, once you have
sent a plot to the mill cpu, you can recycle the plot from
the mill just by pushing a button. It's cpu has about 32k of
internal ram (you can add more, battery backed if needed).
If you use their software, it runs as an ADI plotter direct from
Acad so you don't have to bail out when you want to run a plot.

Doug Dulmage

Techno: 516 328-3970
Synrad: 206 483-6100
Me @ ChromaTek:612 935-8134