Dual Sided PCB with Press-n-peel & Iron

[yolan]

press n peel farnell

Does anyone have a good method for lining up two sided PCB designs when using an iron and press-n-peel materials? The last method we tried was ironing one side, drilling two of the holes, then using drill bits through the paper on the other side to line up the diagram. We were pretty close, but it wasn't close enough. We were also using regular printer paper for the transfer so the transfer wasn't as clean as it could have been with the press-n-peel material.

Yolan

 

[FoxyRick]

pcb peel iron

You've used the best method, in my opinion. You won't reliably got much closer with any method, but it should be possible to get close enough for 'hobbiest' grade designs. Are you doing particularly fine pitch work?

I use transparencies and UV light, aligning the two transparency layers with a vertical microscope for detailed stuff, with the transparencies seperated around the edge of the pcb with pcb offcuts to keep the spacing constant.

Have you though of using half-thickness single-sided PCB? I've seen 0.8mm board and often thought to try making each side seperately, then doing the drilling and aligning. Should be able to get it more accurate as the layes can be moved around until they are close enough, then solder in a couple of links. It still depends on the artwork being accurate though, if it's not, you're stuck. That applies to any method though.

You could add epoxy resin between the boards before you align them, to make a solid, single PCB.

FoxyRick.

 

[bbarney]

press n peel paper suppliers

I've just made a couple boards like Ricks talking about.I used 2 seperate 1/32" boards and glued them and they line up perfect both times and the finnished board is 1/16" thick like a standard board.now the only problem is some simple way of making plated through via's instead of soldering a wire

 

[yolan]

how to align 2 sided pcb

Does Radio Shack carry the single sided PCBs or do you have a recommendation of a good place to get them?

 

[bbarney]

dual sided pcb

you would have to check,but i doubt they carry 1/32" thick boards.i would check the electronic suppliers in your area first than try digi-key or mouser

http://dkc1.digikey.com/ca/digihome.html

http://www.mouser.com/index.cfm?handler=home

 

[yolan]

So here's what I found

PC57-ND PC57 PCB COPPER CLAD 6 X 9" 1 SIDE Injectorall Electronics 6" x 9" (152.4mm x 228.6mm) Uncoated Copper Clad Copper Clad - Single Sided, 1 oz. 1/32" (0.79mm)
62
7.78000
1
-
https://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=182638&Row=529703&Site=US

 

[FoxyRick]

@bbarney,

Thanks for the confirmation that the method works, I'll definately try it myself next time I make a complex board.

Have you seen the copperset system of repariing plated-through holes? That's what I use and it works very well.

They are a plated tube, available in 0.8, 1.0 and 1.2mm diameter and filled with solder. It is inserted into a hole in the PCB (0.05mm wider than the bail). Then you place the PCB on a flat metal plate (aluminium block) and use a centre-punch with the end filed flat on the other side of the bail to splay out the ends over the copper track. Then reverse the board and do the same on the other side. Now, solder the bail on both sides and use solder wick to remove the excess solder from inside. You know have a plated through hole!

I have done a lot of these, using them on components (mainly multi-pin connectors) where you need a solder joint on top, but it is under the component. I have not had a single failure (yet).

Here are the bails, on farnell:

https://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=463929&N=401

Also useful, is an old-style Pentel automatic pencil for 1mm lead. They are mustard coloured and have a steel nib. This is the ideal size (for the 0.8mm bails) to put the bail strips in, and two clicks gives the length of a bail - easy to insert and snap off in the hole.

Give it a try if you can get hold of the bails.

Cheers,
FoxyRick.

Edit: If you want presensitized 0.8mm board for UV exposure, I buy mine from Mega:

https://www.megauk.com/pcb_laminates.php

 

[yolan]

Well, I tried the suggested method for two sided boards last night. It seems to have worked really well. Instead of drilling the holes before gluing and aligning by using the holes, we lined the boards up using the light. The particular pcb I got was really clear after etching so it worked wonderfully to just hold the front and back up to the light. I start soldering components later today, so we'll see how well it worked. Thanks for the suggestions.

Yolan