Experimenting with Toner Transfer

Submitted by Laen on Tue, 2009-04-28 00:58

I spent some time over the weekend trying to see what my board etching capabilities actually are. I use toner transfer, and I thought that kind of limited my options, as far as how fine of detail I could get. I made this test pattern with a variety of surface mount components and line sizes, then tried to transfer them to copper with a couple of different methods.

First, I used a clothes iron, several different temperature settings and applying differing amounts of pressure. This is the one that turned out the best:
Experimenting with Toner Transfer
(Full resolution)

Then, I switched to a laminator. After sending it through a dozen times (top and bottom), I got this:
Experimenting with Toner Transfer
(Full Resolution)
MUCH better. I can do .001" lines sometimes, and .005" lines consistently. I can _almost_ do TFQP-100, and I can certainly do any of the other TQFPs.

I'd really love to see higher-resolution pictures of your boards, or perhaps take a look at them at the next meeting? Especially once you've etched them. That's where the rubber (etchant) meets the road (copper)...

Yeah, would be nice to be able to zoom way in on those to see just how fine the stuff is. Jared has a good point about the post-etch results (let's see em!), but in my experience you can tell 80% of how things will turn out by looking at the heat-press result. There may just be a laminator in my future.... -jason http://noisybox.net

In flickr, you can go to "all sizes" and see the full res version. I've added links under the photos.

I'm saying this as someone who's never actually etched his own boards, but is very familiar with the process, has developed photographs, and also done a lot of soft metal work in a prior life... What I want to know is how you prep your boards before etching? It looks like you sand it somehow. What abrasive do you use -- fine sand paper? Scotchbrite pad? What color Scotchbrite? I ask because, considering the pitch of the lines you're etching, the coarseness of the surface could very well be a limiting factor in your resolution. If you finished with the finest Scotchbrite you could find, or even with sanding with a lubricant (increasing your effective "grit" substantially), would it improve your resolution and the consistency of the lines? Of course, you're already getting great results, so perhaps I'm just "ricing" this topic...

Yeah, that's Scotchbrite (green) plus some Comet, but in truth, the Comet's pretty much gone by the end of my scrubbing. I didn't know scotchbrite even came in different coarseness. I'll stop by home depot tomorrow and give it a try. Thanks for the tip!