halbert@pbsvax.dec.com (Dan Halbert HLO2-3/M08 DTN 225-6305) (07/07/87)
I have used the TEC-200 PC board photocopier film which mjj mentioned in a previous message. It works approximately as advertised, but I have had the following problems with it: 1. If your photocopier does not produce dense black output, you will not get a dense, gap-free transfer onto the PC board. The instructions that come with the film say that the the transfer process (done with a hot clothes iron) will tend to fill in the gaps, but this doesn't work perfectly. I had to go over the pattern with a resist marking pen. I would have used a better copier, but it would not take the film in its paper feeder. 2. The transfer will be a mirror image of what was copied. In most cases, you must therefore make an intermediate transparency. This compounds problem 1. 3. My copier apparently does not copy exactly 1:1, so the spacing on IC sockets, etc. was not exactly right. Again, problem 2 will make this worse. My IC socket had to have its pins splayed. 4. Completely transferring the pattern with the iron takes a little practice. The film looks like overhead transparency film. I have tried some kinds we have around the office, but without much success. But there may be certain brands that work better. --Dan Halbert
randys@mipon3.intel.com (Randy Steck) (07/10/87)
We have one guy here that has been using regular transparencies (you know, like the ones for overhead projectors) to make PC boards. The trick is to design your PC board to scale with some computer system that can output to a laser printer. A MAC or possibly a PC clone with graphics should be okay. Then you take the output and run it through the thermal machine. My friend typically uses two of these and stacks them to block out as much light as possible. Of course, the trick in all this is to make sure you get the scale exactly right and then to get the transparency dark enough. The results that I have seen are impressive for such a kluge. Randy Steck Intel Corp. ....intelca!mipos3!omepd!mipon3!randys