Tuesday, October 26, 2010

Making PCBs using the toner transfer method

Last year the folk at CCHS, my local hackerspace, did some work on producing PCBs using the photo resist method.

Because I don't have a UV box, and because I'd rather not keep buying UV sensitised PCB, I have been looking at the "toner transfer" method.


Most people use glossy magazine paper, or glossy inkjet paper.  I have been looking at other transfer materials.

Last year, I was using the slippery backing paper from sheets of labels.  This didn't transfer too badly, but I did have somewhat of a problem of small sections of track flaking away from the backing paper before I could do the transfer.  Also, I don't have much of the backing paper.

Last night I got to thinking of other transfer materials.  Something I can print on, but would be willing to give up the toner when it's heated.  I decided to try aluminium foil.

I've done some searching this morning, and it seems I'm not the first to think of using foil:


Well, I did several experiments last night, what I can report is that the tracks on the aluminium foil transfer very nicely to the copper.  If the heat is right, there's absolutely no toner left on the aluminium, and the foil can be quickly and cleanly peeled back to leave the tracks of toner on the PCB.

The artwork I'm using has SMT ICs of 0.6mm pitch, which means the tracks have to be really precise.  I haven't yet got one that's of sufficient quality to etch, but I think I'm very close.  Some of my attempts have had great tracks in the middle, but lost some tracks at the edge.  Some of the attempts have had 100% transfer to the copper, but are a little smudged.  I don't think this problem is because I'm using foil as a transfer medium.  Rather, I think it's a problem with the way I'm doing the ironing to transfer the image.  If I can refine the heating process, I think I can produce very high quality boards.  I'd expect to be able to do thinner than the 0.6mm our group can get with the photo resist process.

I think I'll look into getting a laminating machine.  More results to follow.

1 comment:

  1. This guy knows what he's doing. Also, he has a test image that I might try: