Double sided PCB making

[Malc C]

Hi,

I've been working on a project in Eagle that is impossible to route as a single layer. Having resorted to a two-layer board, I'm off to obtain some double sided copper clad board in the morning, however I have never made a dual later board before, and would like to know the best way to get the track patterns to line up, especially as there are quite a few through board connections.

Thanks in advance

Cheers

[Zlatko]

Hi Mal,

I use the laser printer transfer method.
For 2 sided PCBs, I first transfer the toner to one side and apply clear packaging tape to the side I want to protect, then etch the toner side.

After one side is etched, I either trim the PCB to the right size ( so I can use the PCB outline to line up the reverse tracks ) and / or drill a few holes if there are vias on the PCB.

I then remove the packaging tape and clean up the "virgin" copper side and apply the toner tracks very carefully using light to align the holes / PCB with the new artwork. I use a bit of sticky tape to hold the toner paper in place before ironing it on.

Once ironed on, I use more clear packaging tape to completely cover the previously etched tracks and finally etch the second side.

The clear packaging tape works well protecting copper from etchant and haven't had any problems with it yet.

Take your time cleaning up the PCB, applying the clear packaging tape and aligning the artwork to the second side.

Cheers

[Malc C]

Thanks for the tips.

I was wondering if it was best to do one side at a time, but couldn't think of a way for protecting the copper on one side whilst the other was being etched. I'll add some clear packing tape to my shopping list :)

As you will see by the image attached, I'm not starting with a simple layout :eek:

[Comatose]

I etch two single sided boards, then drill them. Use the drills as alignment holes and the components/via wires to hold the whole mess together. Run thin CA between the boards when you're done.

[Gary Warner]

For out-of-house 2 sides, I'm using Pad2Pad (http://www.pad2pad.com).

3"x4" X 4 boards, dual sided with solder mask & silk screening, unlimited via's and holes, 12 days delivery $77. Hamster PCB's $0.69 each (before shipping). Free CAD too.

Is anyone else using a PCB house that's cheaper?

[pmackenzie]

For out-of-house 2 sides, I'm using Pad2Pad (http://www.pad2pad.com).

3"x4" X 4 boards, dual sided with solder mask & silk screening, unlimited via's and holes, 12 days delivery $77. Hamster PCB's $0.69 each (before shipping). Free CAD too.

Is anyone else using a PCB house that's cheaper?

Hamster PCB's? :confused:
Pat MacKenzie

[Gary Warner]

Hamster PCB's? :confused:
Pat MacKenzie

Automatic yaw correction device.

Gary
--

[ElectroLawndart]

Hi All,

I use Press and Peel film. After I print both sides on the laser printer, hold them up to the light, line them up face to face and staple three edges making a pocket. Make sure that you leave about 1-1/2" to 2" border from the artwork. Place a double-sided board inside and iron one side on a wood surface. The heat that bleeds through the board will tack the film down on the other side but not bond it completely. You will have to flip the board/artwork over and iron the back also. Let cool, cut the staples out, carefully peel back the film from the edges, re-ironing as necessary.

Hope this helps.

Dart

[westfw]

As you will see by the image attached, I'm not starting with a simple layout

Hmm. It doesn't look like it should be impossible to route single sided,
based on the functionality rather than the connectivity. Can you move
different functions to different pins? There's no reason LED2 has to be
bit2 of some port, for instance; that MIGHT be easy enough to fix in SW.
(of course to do this you have to have complete control over the SW, and
enough space to do some bit manipulation to translate...)

BillW

[Malc C]

Dart, thanks for the tip. I might try tape rather than staples as I tend to use a laminator to apply the heat & pressure

Bill, I agree, but a friend designed / wrote the software for me and he'll start charging me if I now ask him to chang it :)

[simingx]

How about using wire links? It looks like the layout could be optimized somewhat.
(Just pressing the Autoroute button in PCB software usually creates chaos.. ;) )

[Malc C]

I agree, give time I could manually rout the thing better than the auto-router... but time is not on my side and I need to get this built soon :)

I got 100% the first time it was run so I kept it that way !