a tight cable and pulleys setup has worked for dot matrix printers for years for positioning back and forth. if you find the right old printer, that assembly can be removed and used, including the stepper.
for a tightly focused laser perhaps the laser assembly from a laser printer. it would work if you could mount it at the exact distance as it was in the original printer (it's focal point) from a new larger drum or platen(?i think that's the term).
of course, taking two printers apart to do the same thing a laser printer does anyway, may not be the most direct solution, but where's the fun in that?.
----- Original Message -----
From: Adam Seychell
To: Homebrew_PCBs@yahoogroups.com
Sent: Tuesday, April 09, 2002 10:03 PM
Subject: [Homebrew_PCBs] laser diode photoplotter
Hello group,
Has anyone here thought about building or even built a drum
photoplotter based on a red LED laser diode ? This would be used for
making printing masks, et. There has been much discussion among amateurs
on building a CNC mill/drill machines, however I am under the impression
that this is definitely NOT an task for the beginner, even if he/she
has access the right tools. A drum photoplotter appears simpler in
construction as there is only 1 axis required to position the light
head. Basically the drum plotter works by rotating a relatively large
drum with a film sensitive to red light (available from Kodak)
positioned around the outside of the drum. The drum spins at fairly high
speed (> 10 rev/sec) and the light source (red LED laser diode and
focusing lens) slowly and accurately moves along the length of the drum
in a straight line. The spinning drum sounds relatively simple to build.
The moving light source looks a lot more complicated / expensive. My
only thoughts how to go about this is to use a ball bearing screw and
linear bearing. I priced some ready to go ball screw guided assemblies
but the costs were prohibitive. Is there no other option ? I own a drill
press and a small lathe in my workshop. I am open to all comments.
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