Homebrew PCBs

On 08/30/2010 06:41 PM, Chris wrote:
> forget the dry film for reliability.

I've figured out how to laminate the dry film with nearly 100% success. 
  I have two ways - wet or dry.

Wet
---

Similar to Adam's method, I put the film stick-side up on a plastic 
sheet, rinse, and flip the sheet over onto the PCB.  This lets me 
squeegie out the water without actually touching the film (the plastic 
sheet protects it).  Once most of the water is squeegied out, I run it 
through the laminator set to 200 F (96 C) - below the boiling point of 
water, so no steam bubbles.

Dry
---

Get a clean sheet of paper a bit bigger than the PCB, plus a few inches 
more sticking out the top (the edge that goes into the laminator first). 
  Put the PCB on it.  Cut some film as wide as the PCB and 1-2 inches 
longer. Tape the leading edge of the film down (stick-side towards 
paper) just ahead of the PCB.  Cut two 2" long strips of paper, tape one 
to each trailing corner has handles.

Put the assembly on the feed side of the laminator set to 240 F and get 
it started.  Once the paper is grabbed, pick up the paper handles and 
lift the film off the pcb, pulling gently back and apart.  This makes 
sure the film first touches the pcb at the roller, so no air can be 
trapped.  The handles also let you put tension on the film right up to 
the moment it goes through the rollers.

(hmmm, I wonder if I can just put the board through upside-down so 
gravity keeps the film off for me)


In both cases, for double sided I just repeat on the other side.

The Dry method doesn't work on aluminum foil (for solder paste 
stencils), but I've yet to try the wet method with it.  The foil itself 
wrinkles on its way through the laminator, hopefully the wet-stuck film 
will help keep it straight.  Maybe I'll tape the foil to a carrier too.