DIY PCBs

I've been making one off boards for years with photo resist board. I don't use any other method to prototype a circuit these days. If you're pushed for time it's a lot better than waiting a for boards from a PCB house. Single sided are a breeze and double sided aren't difficult even with ground planes. I can have a 3x3 inch board etched and drilled in an hour or so.

If you use GC-Prevue to import the Gerber and Excellon files you can check your artwork and print onto inkjet film if it's OK. You can get a good contact print if you hold the film and photo board between 2 sheets of glass with bulldog clips and expose for about 5 minutes. Develop with NaOH and etch with FeCl3. Drilling the holes is easy. The drill finds the centre of the pads just like it would with a centre-punch mark. For a really good PCB you can use tin plate solution to finish off.

Richard

I like single sided with ground plane on the other side. You only need to expose one side, then drill through and link with tinned copper wire. I only tend to use it for prototyping slightly tricky, yet basically simple analog stuff though, like SMPS chips or RF. Also good for making connector adapters for prototyping.

Another point would be to use Ammonium Persulfate etchant. It's much cleaner than ferric chloride. The reaction products are water soluble, you just end up with a light blue coloured solution. I think it has a shorter shelf life when in solution, but can be rejuvenated by topping up occasionally with fresh crystals.

A friend of mine uses the backing paper from the laserprintable stickly label stock. He just cannot wait to collect it from the dust bin after a secretary prints some labels. Has exactly the right release and texture for toner transfer using a hot press. I'll ask him which brand of sticky label they use.

Steve

here:

Anyway,

Then make your own pad per hole with this

Vector used to make a board about 4 x 5 inches, holes on the .1" grid, with one side copper plated with little donuts around the holes - a dandy ground "plane" ("Holey plane, Batman") and pad per hole on the other side. There were also traces around the perimeter, and either a connection area or an edge connector on one end; I don't recall which. Vector doesn't seem to have them on their website - maybe there just weren't enough customers. )-;

Anyway, instead of laying out a board and etching it, I'd take one of those babies and just build the circuit on the spot, using #30 wire-wrap wire. ;-)

Of course, if it was going into production, then I'd bother to lay it out. Hmmm ... maybe that's because I don't like doing layout? ;-)

Cheers! Rich

com/

Thanks guys for your suggestions. Appreciated. The reason for DIY in this case rather than sending them out initially for fabrication was it is a prototype design. Also there is more than one board design for the entire product. As performance of the product is layout dependant, I'd rather get it correct before sending the design out for mass production. Besides I might have got something wrong. It would be a tad embarrasing to send out an order with a mistake in it, only to end up with a stack of landfill. :-(

Once again, thanks for your suggestions and input.

Alan

I used to cut the film and tape it to paper then feed in the paper. never had a wrinkle problem, stuff worked very well.

Cheers

Sounds like your laser needs a new cleaning pad. They're impregnated with silicon oil to keep the hot roller from sticking to the prints. You also need need a straight paper path for thick/stiff sheets, so if your laser has the option, flip down the back flap so that the sheet exits at the rear instead at the top.

Same here. With a bit of care, it can even look nice.

Ayup. I like to work from an Eagle layout instead of a hand drawn layout if there's more than one chip, as it makes it easier to catch mistakes.

Oh boy, that sure brings back memories! ;^)

I've used Avery brand before, but that was for transfer onto fabric. I ran it through the photocopier about 10 times replacing it carefully in the tray after each run to get the same registration.

in case it's not obvious: print on the shiny side.

the stuff seems to be reusable.

A multi-board project is even more reason to ship the job to a pcb fab. Ones that I use treat a panel of layouts as one job for setup charge purposes, but still separate them for me. Doing things this way has the disadvantage of turnaround time, but two clear advantages:

1. the board matches the final job quality; and
2. it saves the hard work/mess of DIY which is especially a PITA with fine tracks/spacings (and kludging PTH functionality) .

Just my belated 2c worth, as I have long ago given up the DIY board approach.

from

tyry

Are we going to discuss this again: =20

com/

Richard, I just sent you an email but it got kicked back, so I will try to contact you through here.... =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Mr. Swaby, I just saw your May5 response to a discussion about making your own PCB boards.

I have designed PCBs for years and I used to run a PCB design department. I now run my own electronic design business and I would like to be able to fabricate my own PCB prototypes. I agree with some of the people that ordering them from a low quantity PCB house is nice, but as you pointed out waiting for the turn-time (or paying expedite) is the issue.

Where are you located? Would you be willing to train me and my PCB designer how to make your own boards with photo-etching, etc? I can pay you. I was thinking of getting one of these "rapid prototyping" systems, but I'm not sure...

I hope to hear from you. Respectfully, Steve French

President, Volt Vision