Note: This circuit is uber simple and has no components on it.. its just a bit of printed cabling. If this is going to bore you, move on...
A co-worker's project has a bunch of Adafruit Neopixel strips glued together which need the data lines connected down one end for the data line so the matrix works correctly. Nobody else here is much into electronics or solider, so I used this as an excuse to try printing on plastic film rather than soldering wires on. The connection cant really stick out in any direction because of how this is going to be mounted.
The film of choice is of course Kapton, specifically McMaster part # 2271K24 - Kapton ® Polyimide Film, Thermally Conductive, .002" Thick, 12" x 12" - $27.00 Each
This is the electronics specific stuff, being thermal conductive. They have other grades of kapton in other thicknesses too.
But, to throw a spanner in the works... i'm also trying on mystery film... its mystery because its one of these two:
* McMaster 84955K24 - PFA Film, .002" Thick, 24" Width $11.77 per Foot
* McMaster 85905K64 - FEP Film, .002" Thick x 24" Wide $8.04 per Foot
The labels fell off during transit, so I have no idea which roll of plastic is which. One looked like it was dragged across their whole warehouse floor - totally covered in grit and fluff and rubbish, the other was marginally better.
The two clear films are very soft and supple, and shiny. You can draw on the kapton with a roller ball pen, the clear plastic i'm using has no such luck, as it just beads up. Kapton cuts wonderfully with scissors, the clear film was quite difficult to cut with the scissors I have (which keep getting stolen by the composites lab to cut up their sand paper!)
Both of the clear films need to be 2-4x thicker to be of any use in my opinion.
I'm using a piece of a H-Bridge test board under each clamp which I cut off with the composites bandsaw to clamp the film down with.
Kapton test prints wonderfully:
and my "circuit" came out well also
The clear film was very clingy with the amount of static on it, so I didnt re-probe the bed before printing, since it's the same thickness as the kapton. I didnt hold much hope of it printing well, but this ink is pretty incredible and the print came out well. This means I didnt need to do another calibration print as well.
The films are now baking, with an earlier board on FR4 upside down over them. Due to how thin and flexible they are, they are baking ink side up rather than down.
The Kapton is flexing a little as it goes under heat, photo below is at 230c. The little strip of FR4 on it is because I was worried it would curl up and maybe mess with my print in the middle of the board that is face down.
The film on the other hand is quite wavy at temperature as it seems to expand quite a bit. If I can find a clear high temp film that works for "floating" leds and such, that would be amazing. I'd be interested in perhaps testing this film with a bit of tension on it, or perhaps just clamped down for baking and reflow
