owhite@nmsu.edu (smouldering dog) (02/12/91)
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
useful. I would be particularly interested in it if you can run the
TEC-200 thru a laser printer and if it doesn't require specialized
copper-clad boards. I would guess that other sci.electronic netters
would like to hear your experiences so why not post on the net?
--
owen white (owhite@nmsu.edu)
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got my head on a pole (for better reception)
-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-=-*-=-*-=-=-*-=-teodor@acsu.buffalo.edu (Dan C. Teodor) (02/12/91)
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