Jon Elson wrote:
steamer wrote:


Jon Elson wrote:

This stuff isn't that hard to do yourself, even, if you have a way to
make the master films. I make solder paste stencils this way. I use
.003" brass shim stock, and laminate dry film photoresist to both sides.
I make mirror-image films with a photoplotter and align them to each
other. I then slip the sensitized brass between the films and expose both
sides
to UV from the filtered black light bulbs. Develop the photoresist in
sodium carbonate and then etch with ferric chloride in a double-sided
spray etcher. I've gotten down to .010" apertures or thereabouts.

--This sounds fascinating. I'd looove to see a photo essay of you
doing this. Got any links??



Hmmm, well, not really. I do have some stuff on my web pages showing
some of the gear. Here's a poor picture of the laser photoplotter.
http://pico-systems.com/photoplot.html


A nice little project you have there. Do you get much trouble with
temperature stability. I ask as my local photo plotter mentioned that
they keep the plotter in a temperature controlled room and also that the
film itself is quite sensitive to temperature changes. IIRC their photo
plotter was 2000DPI for normal use but could go higher and the sheets
were about 2ft x 2ft.

I put litho film on the drum, it records the image in a raster
fashion, building up the image at .6 inches/minute. Develop
with usual photo chemistry.

I snagged a Kepro dry film laminator on eBay years ago. It
is made for laminating the resist to PC boards, but if you
put a shim of several sheets of heavy paper under the brass
shim stock, it laminates perfectly to thin shim stock, too.
You put the resist on both sides, and then expose with mirror-image
photo masters. The resist is developed and then put in a
Kepro spray etching machine that I got just before it hit the dumpster
at work.

I used to use this gear to make PC boards, but they make these so
cheap in China now that I rarely make my own. (I have scraps
left over from so many projects that I can usually find a board
that can be re-purposed for new experimental projects.)

I built the photoplotter myself. The machine wasn't too hard to
make, once diode lasers came out. The software was a lot
harder to do.

I've got some pics and story about getting the Philips pick
and place machine in my basement. That was an ORDEAL!

Jon