DIY Double sided Presensitized PCB at home

[glenndr_15]

Hope this can help people who want to try Double sided PCB using Presensitized PCB.
Here is the link: http://glenndr15.wordpress.com/diy-double-sided-presensitized-pcb/

Best regards,
glenndr_15

[slackdick]

Great video - some handy tips.
The biggest trouble I always have when making doubled sided boards is getting the two sides to line up accurately - i like the use of clips suggested here to aid this.
Thanks.

[robotai]

I am too stupid to see how he did the alignment.

Did he cut the transparencies to the same size and align them? Or some other way?

[slackdick]

I think he has aligned the transparencies and fixed them together at one end (they both extend beyond the board by some distance) and then inserted the board between them.  This can work well for smaller boards but can get problematic on bigger areas (or thicker material).

[glenndr_15]

I am too stupid to see how he did the alignment.

Did he cut the transparencies to the same size and align them? Or some other way?

No I did not cut the transparencies on the same size. For example, on the top pattern one of the transparencies is smaller and the other is larger so I can align them and use scotch tape to stick the smaller pattern on the larger pattern. I aligned the top and bottom transparencies based on the dimension of the board and the holes as reference.

[glenndr_15]

I think he has aligned the transparencies and fixed them together at one end (they both extend beyond the board by some distance) and then inserted the board between them.  This can work well for smaller boards but can get problematic on bigger areas (or thicker material).

You're right I aligned the transparencies and fixed them together at one end. I used scotch tape to fixed the top and bottom transparencies.

[FTL]

Very nice video showing the process. Thanks for making and posting it.

Can I make one suggestion? When you line up and tape together the transparancies, place a small strip of PCB material, or similar thickness cardboard between them. Then tape it together with the filler.

That way when the PCB material is inserted it will not pull the images slighlty out of alignment because one is bending up while the other one is flat. it will probably help keep it all flat during the exposure as well.

[mick the mend]

I have found the best way to keep allignment is to fix the transparencies with 2 pieces of double sided foam tape to form a corner for the board to rest against. Over the years I have managed to find a few different tapes that are the same thickness as the pcb from DIY or 'Pound' shops.

best of luck

[LithiumOverdosE]

When you're done with one side just drill a few holes on the pads or vias on a few places on the PCB. You can then perfectly centre everything on both sides.

I found this method to be more reliable when taken into account that printers and photocopier machines distort layout to a certain extent.

[Delillusions]

Hi!
Personally I use two techniques to make my own PCBs (both for single and double sided).
#1 Ironing technique: For this one I use some reference holes.
# UV exposure: For this aligning the masks and taping them together worked me greatly this far. For better alignment I usually make a few vias with smaller drill holes and I'm using them as reference points.

[f22kma]

At my last job, we did a few prototypes with a CNC router.

For thin substrates we used a vacuum chuck underneath to keep the board flat. We even glued two double sided boards together to make a four layer board a few times.

But with fast turn around PCB service, it usually wasn't worth the trouble.