PCB Prototyping

September 28, 2006 8:52 AM

Is there a simple way to do a PCB prototype?

I have laid out an circuit using Protel, and now I am ready to send the board out for production. However, before I do this, I would like to run a prototype of the board on my own. Is there any easy way to a quick prototype of the board before I send it out to a production house to do a large run?

posted by vansly to Technology (9 answers total)

We always used to have our production house do us a prototype for approval before we'd commit to an order of hundreds. If your production house won't do this for you, get a different production house.
posted by flabdablet at 8:58 AM on September 28, 2006

If it's a simple single layer board with no vias, and you just want the prototype to check that the thing will actually work, rather than to see what quality of board you're about to order hundreds of, you can certainly make one yourself.

Just print the layout on acetate sheet with a laser printer; print it flipped, so it looks right when viewed through the acetate; then clamp it onto a photoresist coated board, toner side toward the photoresist, on a UV lightbox, expose, develop, etch, drill.

Personally I'd have the production house do it unless it's really really simple.
posted by flabdablet at 9:03 AM on September 28, 2006

I've etched a board once in my life and it wasn't very hard. The only issue is that if you have really, really fine traces, a standard laser printer may not be able to do them properly (i.e. you get one big trace or no traces at all).

But if your board is pretty simple, it should be easy. Try Jameco or Radio Shack has a etching kit (though it comes with a pen and I duuno about doing a UV transfer with that kit).
posted by GuyZero at 9:16 AM on September 28, 2006

Here is another way to make your own PCB using a laser printer to make the resist - it is transferred onto the copper with a clothes iron and then etched.
posted by exogenous at 9:16 AM on September 28, 2006

Check out the prototype PCB service at
http://www.sparkfun.com
$2.50/sq. inch (or maybe $5.00, I forget)
(No connection, except as a satisfied customer).
posted by spacewrench at 9:36 AM on September 28, 2006

If you google up "prototype PCB" you will find dozens of companies that will do small runs in as little as four days for less than $100. For anything more complex than four layers and 10 mil traces, though, it is better to get prototypes from the same vendor as the production run to ensure that the processes and quality are the same. Ability to control impedances can vary from vendor to vendor if that is important to you.
posted by JackFlash at 9:43 AM on September 28, 2006

If you etch yourself (which I've done), please do appropriate disposal of the spent etchant. Don't just dump it down the sink. In my case, the drain line on the sink was copper and even though I swear to this day that I flushed it thoroughly, my dad ended up having to replace that pipe after it etched through.
posted by plinth at 10:25 AM on September 28, 2006

Sparkfun's PCB service is great, but it's really targeted at hobbyists who aren't in a hurry. For a commercial prototype, there are a zillion places out there that'll do a quick turn on, say, 3 copies of a board in a week (or as fast as a couple of days). You'll pay $50-$100 more than you would at sparkfun. (Sparkfun's advantage disappears for larger boards, also.)

If you're thinking of doing the prototype manufacturing in-house, I gather that a lot of places have moved to milling their PCB prototypes instead of etching them. I don't know what the pros and cons of milling are, though. (Fewer chemicals but more expensive equipment?)
posted by hattifattener at 10:41 AM on September 28, 2006

My buddy mills his circuit boards but a CNC mill will set you back $1500-$2000 even if you try to do it on the cheap.

If you're doing thru-hole, whether etching or milling the copper, be aware of the need for a carbide drill for the holes.
posted by jepler at 5:10 PM on September 28, 2006