Re: etch resist as solder mask, and laminator discovery
- --- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>Try cold rolling through the laminator first. I find this pushs the air out before hot laminating.
> First, some photos: http://www.delorie.com/pcb/lab/
> I wanted to try this in case I needed it in the future, and this board
> was simple enough that it didn't matter if it worked or not. Got to
> remember to avoid the thin bits of mask between pads, though - they
> easily come loose.
> The discovery is about laminating 1/16" (63 mil) clad. Usually my
> laminator doesn't like accepting these, I have to push pretty hard to
> get it to "catch" and roll through. This time, I was trying to avoid
> air bubbles in the mask. Usually I wrap the film around the leading
> edge of the board, and hold the trailing edge tight, so that air
> bubbles won't get trapped. In this case, I didn't quite have enough
> film (it was a scrap) so I put the pcb on a piece of paper, leaving
> most of the paper on the leading edge side, and taped the film over it
> (taped it to the paper, not the pcb). That way, the laminator could
> grab the paper and I had time to pick up the trailing edge of the film
> and hold it while the laminator pulled in the paper/film/pcb.
> I was expecting problems when the pcb got to the rollers, but it got
> drawn in just as smoothly as the paper! There was a bump when it
> exited, but the lamination was nearly perfect. So I'm thinking, when
> you do 1/16 clad, leave enough of the TT/film/whatever paper on the
> leading edge that you can fold it over enough to tuck under the pcb's
> edge, so that the laminator can grab the fold and draw the PCB in.
> Anyway, back to the mask... after developing, I put it under the UV
> again for 3x my normal exposure to harden it. Any idea how it will
> hold up to soldering? It's Riston.
- "David B" <davidlbarber@...> writes:
> > I was expecting problems when the pcb got to the rollers, but it gotThe discovery isn't about air bubbles, it's about getting 1/16" PCBs
> Try cold rolling through the laminator first. I find this pushs the
> air out before hot laminating.
to *fit* into the laminator. If I hold the end of the film up as it's
entering, I usually don't have problems with air bubbles. *Steam*
bubbles are a different story - but laminating below 212F seems to
solve that problem.