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Help With Eagle PCB Layout Answered

Hello All.

I'm trying to etch a board created in Eagle. 

2 Questions:

When I export the image, the "plastic part" of the pin headers on my board are showing up in the exported image.

Is this image really "doable" using a toner transfer method due to the thin clearances and trace widths?

Exports of the schematic and board images are attached.




I've never personally etched a board, just done a lot of reading on the subject, so bear that in mind when taking any advice from me.

The traces do look quite thin. An experienced PCB etcher could probably be careful enough to get them to all work out. Total noobs like you and me, however, would be more likely to get a sloppy transfer and mangle the traces. There is an OLD Instructable from westfw that details a method for making the traces thicker and increasing tolerences overall. Check his Member page, too, he has some other Instructables related to PCB manufacture using Eagle as well.

Final thought: why is the board so wide? If it doesn't have to be that wide to fit components, you could shrink it down, and have half the piece of copper-clad left over to make another one if you mess up on your first try.

I've run through some of westfw's instructable before, but I violate most of it just because the traces have to run through the pin headers on my board and the are just that thin.

The board is long because it's a shield for an Arduino, and the 2 small connectors are on the right are for ribbon cables and they have to clear the Arduino. 

I  hadn't thought about the large amount of copper having to be etched, that's a great point.  Even if I can't make large planes for GND, etc.  the least is  could do is fill them in.



8 years ago

Those traces look fairly standard to me. There's nothing really wrong with narrow traces (SMD traces would be much smaller), other than the "toner transfer" method itself. I tried it several times, and never was satisfied.

It's a little finicky; you really need the right paper to make it work, and the right "touch"... Expect several failures with the toner transfer in the beginning...at best.

(I'd personally recommend presensitized boards. You can use inkjet transparencies with that method.)

I agree with PKM. All that "white space" will exhaust your etchant. Here's a ground-plane tutorial for eagle that might be helpful. It might not fill in the inner voids, however, due to the distance between pins and the "minimum clearance" settings for the plane...


8 years ago

We were always told to "block in"- fill in big white areas with trace, because it means there is less to etch and so
a) you get a more even etch
b) you use less etchant

Of course, if toner is more of a cost concern than etchant feel free to disregard point b, but I think it still results in a neater etch.  I also don't know how it interacts with toner transfer...  FWIW I'd be tempted to make the traces bigger and the gaps smaller, joins are easier to correct (craft knife) than gaps (painstaking soldering bridges).

Ok, I found the place where this is controlled.  View>Hide/Display Layers. 

Still wondering if this is doable by a noob hobbyist.