🚀 go-pugleaf

In article <OWHITE.91Feb11092630@haywire.nmsu.edu> owhite@nmsu.edu (smouldering dog) writes:
>I was looking in the recent edition of radio electronics, march '91 pg
>52oo and in an advertisement from DC electronics (scottsdale AZ) there
>is a description for a method of pcb fabrication that goes like
>this:
>	-copy circuit pattern on TEC-200 film using any plain paper
>copier. 
>	-iron film onto copper clad board.
>	-peel off film and etch.
>
>has anybody had any experience with this stuff?  it sounds reasonably

Here's a side note from somebody who has been improvising backroom
electronics for a few years now, mainly due to a lack of funds. Don't
laugh, this actually works (proven on many late night in the lab of
Lasercad Inc. Farmingdale, NY).

1) If you have the circuit routed already, gr8, ignore steps 1x.

1a) Create object database in what-have you (Autocad in my case).
1b) Route.
1c) Take E-size mylar and tape film to exact geographic center of it.
    Lay film in flatbed plotter.
1d) Plot routed image onto film WITH FELT TIP pens, othertypes will etch
    the film and severly reduce the transference rate of the ink.
1e) Pull film off mylar and don't let it sit around too long, you want
    the ink as fresh as possible. Crop to size of image (as close as you
    can) with X-acto.

2)  Place the film, printed side down onto copper board and run both through
    (like I said, don't laugh) a hot wax application machine for skis
    (obviously forget the wax).

3) Etch.

Side notes and abortive methods (all time tested by yours truly):

A) 24-pin dot matrix printers DO NOT WORK!! Wrong kind of ink. You get
   circuit breaks where they are supposed to be continuous about every
   1/50th of an inch.

B) Laser printers generally produce very poor results because (due to 
   static electricity present in even the most properly grounded 
   environments) the drum get ionized where it's not supposed to and
   will pick up a random fleck of dry ink and drop it on the film. That
   little fleck, in my case fell between the input leads to an op-amp
   allowing the charge from the source not to drain through the proper
   resistors but into the op-amp. Needless to say, the results were
   spectacular (the transient before the chip blew apart sent even a
   Tek oscilloscope for a blink). Since paper copiers use the same
   priciple as laser printers, I would also dissuade their use.

C) MAKE SURE THE TRANSMISSION LINE BETWEEN THE CPU AND PLOTTING DEVICE
   IS CLEAN AND CROSS-TALK FREE! The one biggest nightmare. Took me
   a full three days to figure out with a pen was giving me the 
   opening strings from Blue Danube instead of a straight vector.

D) Cover the hot rollers in the wax applier with rice paper and dispose
   of the rice paper after every use. Beleive me, it'll save you a nightmare.
   It's not so much that ink get left over from print to print but your
   fingers do more damage in getting ink on the rollers that put through
   random dots and smudges.



Well, that's about all I can think of right now. I haven't done this in
quite a while (going on three years now) so I probably forgot some small
but essential detail somewhere in there. If I did and you go ahead and
try this, I'm sure you'll discover it and find some other new and
ingenious method to rectify it. Best of luck!

Dan C. Teodor

v083pzgu@ubvms.cc.buffalo.edu
teodor@sun.acsu.buffalo.edu