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View Full Version : Lining up double sided pcb's



ctmal
05-22-2011, 09:26 PM
I've been having pretty good luck lately making double sided boards. Since I was etching a board today I figured I'd take pictures and do a step by step on how I've been doing it(just in case it'll help someone).

I've decided to consolidate my projects. You can download this and anything else you're interested in at ctm.maloneylights.com (http://ctm.maloneylights.com/downloads/).

IdunBenhad
05-22-2011, 10:54 PM
Hi:
Good instructions, Chris. Using these should make it easy to get proper registration.

One thing I found was that my printer driver has a mirror function and I use that. I have a Brother 2140 printer.

When transferring the silkscreen to a board, I drill the board after etching and then align the silkscreen with the holes in the board using a small light table. The light shines up through the holes and makes it possible to get a good alignment.

I use Tech Brand "Brake Parts Cleaner" to remove the toner after etching. Carburetor Cleaner works also. I wear rubber gloves. Gloves should also be worn if using Acetone and good ventilation. I usually go outside to clean the boards.

The cleaner is cheap and goes a long way. It is available at Walmart.

I also found that it is best to not use a paper towel to dry the board after cleaning in preparation for toner transfer. Some brands of paper towels have chemical in them and may leave a coating on the board. I use a clean microfiber towel to dry the boards after washing with alcohol.

Just a few tips I found while doing boards.

Thanks for your excellent write-up.

IdunBenhad
05-22-2011, 10:55 PM
Hi:
Mistake: This one was due to a malfunction at the DIYC server. It was a copy of the one above.

christmas-light
05-24-2011, 09:14 AM
I have never tryed this, but this video explain great how to do it ;)

http://www.youtube.com/watch?v=8HJrzaW5B3g

IdunBenhad
05-24-2011, 09:44 AM
Hi:
Christmas-light: That is an interesting and informative video. Using the photoresist method probably allows for more accurate registration of the two sides and smaller traces can be used. There are some good tips in that video. I had never seen the spray solder flux coating.

The only drawback to this method is the number of steps required to get the finished board. The toner transfer method is less time consuming, but one has to be careful about the transfer, as it sometimes can be tricky getting the right amount of heat and pressure.

I have problems with the edges of the boards. I never seem to get the right amount of heat and pressure and usually have to touch up the edges with a Sharpie pen.

I like CTMALs method, but so far I haven't tried it as I haven't had the need for a double-sided board. However, as I described getting the silkscreen on a single sided board is almost the same thing. It just doesn't have to be as accurate.

Thanks, guys, for the information. As AURBO says, "Learn something new everyday"

dirknerkle
05-24-2011, 10:54 AM
I have problems with the edges of the boards. I never seem to get the right amount of heat and pressure and usually have to touch up the edges with a Sharpie pen.



I've found that edges work out much, much better if the edge of the board is not raised, which can easily happen when cutting the board down. After trimming a board to size, I always run a file over the edge where the board was cut so it doesn't create a gap when applying the toner.

More recently, I've been using a common paper cutter to quickly cut through the board. It's noisy as can be, but seems to work quite well. I place the board on the cutter with the copper side up so that the cutter's blade goes through the copper first. Leaves no raised edge. The technique takes a very strong, quick motion, so it can be pretty dangerous if you try to hold the board with your fingers, so watch out or if the board slips, you could quickly lose a finger, too! Instead of using your fingers, sandwich the board under a spare piece of board stock and clamp the board to the cutter.

wonko
05-26-2011, 09:54 AM
I've found that edges work out much, much better if the edge of the board is not raised, which can easily happen when cutting the board down. After trimming a board to size, I always run a file over the edge where the board was cut so it doesn't create a gap when applying the toner.

More recently, I've been using a common paper cutter to quickly cut through the board. It's noisy as can be, but seems to work quite well. I place the board on the cutter with the copper side up so that the cutter's blade goes through the copper first. Leaves no raised edge. The technique takes a very strong, quick motion, so it can be pretty dangerous if you try to hold the board with your fingers, so watch out or if the board slips, you could quickly lose a finger, too! Instead of using your fingers, sandwich the board under a spare piece of board stock and clamp the board to the cutter.

This is what I was doing for a short time, until my el cheapo cutter broke. Just one thing to keep in mind...don't try and use the light weight cheap ones you find around, they just don't hold up. It's back to using the score and snap method for me.

Brian

maffeirw
08-22-2011, 09:03 PM
I've been having pretty good luck lately making double sided boards. Since I was etching a board today I figured I'd take pictures and do a step by step on how I've been doing it(just in case it'll help someone).

10378

Chris - any chance you can repost the dblsidepcb.pdf file, it must be one of the files Brian was talking about in his PM. I'm going to try to do some SSSRR boards tommorow and I think it will come in handy.

ctmal
08-22-2011, 11:19 PM
It's been updated. Let me know how you make out!

hold on, it's not working yet...