Tips on double sided PCBs...

I've started moving away from the protoboard because soldering all those wires is such a PITA but it seems that making PCB's has it's own set of troubles...

I've been fooling with L298's some and figured a breakout board would be a fun first project:

It ended up being a double sided deal and the way I handled it was just to solder both sides where the components mounted. It worked OK but that'll be tough to do on my next project because I'm going to have a female header and I won't have access to the pads underneath.

Does anyone have any tips on how to deal with this? I was thinking that there may be some way of "wicking" solder through the holes before assembly.

Thanks.

For small PCBs, if I only need a few copies (or even one), http://www.oshpark.com/ is hard to beat in my book. For larger boards or more copies, one of these may be more economical: http://iteadstudio.com/store/index.php?main_page=index&cPath=19 http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html?cPath=185

What I did, was bend over one of the pins and solder it on top:

hoff70: Does anyone have any tips on how to deal with this? I was thinking that there may be some way of "wicking" solder through the holes before assembly.

Well, machine produced boards are electroplated. So if you can find a manual method of that, you might be able to create vias. Otherwise, a wire through the hole is how I did it before having Seeedstudio make all my boards.

there may be some way of "wicking" solder through the holes

Nope, there are some little tube things that can be inserted but I don't know what they are called.

female header and I won't have access to the pads underneath.

The standard way is to never have a trace go to that sort of component from the top of the board, place a via a couple of mm away and run the final bit of trace on the solder side.

bend over one of the pins and solder it on top:

That works as well, you could bend them all out and effectively make the socket an SMD.


Rob

Oshpark:

"The standard 2 layer order

$5 per square inch for three copies of your design. For example, a 2 square inch board would cost $10 and you’d get three copies of your board. You can order as many copies as you want, as long as they’re in multiples of three.

Orders are generally 2 to 3 times a week, and have a turn time of about 12 days. They can be ordered on OSH Park."

iteadstudio - 5cm x 5cm (3.875 in^2), double sided, solder masked, stenciled - 10 copies for $10. ~15 day delivery.

Can get a lot into 50mm x 50mm.

If you add thru hole pins
http://www.dipmicro.com/store/0552-2-15-01-11-27-10-0
can also solder from both sides.

Ground planes are always good - less copper to remove if etching at home, helps with cooling, helps with noise.

I agree that OSH Park is great and inexpensive. I use that service often.

As for those boards created at home, you might try experimenting with some soldering paste that will go on the pad below the header before you insert the header and maybe don't squash it all the way down. The heat from the pin, heated from the underside, may be enough to melt it and make a connection. I've never tried it, but worth playing with to see if that will work for you. Be sure to use some low melt point paste like R276 so it is easy to work with.

-John

I have been playing around making PCB’s at home for the last month or two

At the start I knew basically zero, I got eagle and put in a fair bit of time I went for the photoresist method using inkjet transparency film and after trial and error the results are amazing

I have really enjoyed the challenge of making a double sided PCB it took a lot of work I even got the tinning crystals to give the final board more SEX appeal!

Its a motor drive and I needed a laminar bus plane to combat stray inductance

Finally I just have to show off the outputs , two sine waves 90 degree phase shift between

I get real excited every time I see the output!, am I weird? lol

Lots of room for improvement still, my soldering not least i need some kind of temp control for my iron as the black marks take away the sex appeal!, its because of too much heat ... I think

Still its only a prototype and it works well, still a long list of improvements though

Do it yourself is the best IMO

Nice work.

Thanks Crossroads, I have worked pretty hard, Eagle took about as long to work out as did C programming

Any tips?, the black marks for instance am I right to assume its because I have no heat control on my iron? it certainly wasn't any contaminants as I used IPA to clean the board before soldering

Thanks for the tips! Sounds like there isn't any magic bullet...

Nice board resinator! I'm etching mine and using Fritzing. I may try Eagle in the future...

If I needed a bunch of boards I would consider having them made but making my own stuff is pretty rewarding.

I've also have to say nice work. I find the larger boards very difficult to make at home. Anything larger than about 2"x2" and I can't get a uniform development or etch. Some spots are developed too far and others are not developed at all. A properly etched double sided board is virtually impossible for me =(

"Some spots are developed too far and others are not developed at all."

Sounds like a lack of agitation during etching. I wonder if raising the board up with snap-in nylon standoffs would help with getting the etching solution moving around more. I would think that having as much ground plane as possible would also help as less copper would need to be removed.

"Eagle took about as long to work out as did C programming." Yes, can be like solving a puzzle, especially when trying to minimize via's. Simple things like looping a signal in the opposite direction to start seem to be beyond eagle's grasp sometimes.

I've had a fair bit of good luck with "mechanical etching" using a CNC router. Once you get the hang of side-to-side registration, the images line up really well top and bottom. Of course, you need a CNC router too. I really hate having to deal with soldering little pieces of wire through the holes to make the vias though. That is the real downside to making boards at home is no ability to do holes that are plated through. If you have just a couple of vias, it is worth it, but if you end up with a bunch of them, it is best to just send that off to OSH Park and wait the 2.5-3 weeks for it to arrive in the mail.

Your work looks great though :-)

Resinator: Finally I just have to show off the outputs , two sine waves 90 degree phase shift between

I get real excited every time I see the output!, am I weird? lol

That probably depends on who you talk to, but a lot of us here certainly understand it! :D

"NORMAL" is just a cycle on the washing machine...

Thanks for the kind words everybody, I have to recommend the photoresist method it seems much less hassle than the toner transfer method and apparently the results are better

I only use a daylight fluorescent fitting I had laid around, 7-8 minutes is all it takes

Yes, can be like solving a puzzle, especially when trying to minimize via's. Simple things like looping a signal in the opposite direction to start seem to be beyond eagle's grasp sometimes.

I was exaggerating a little :D as when I started to learn C i already knew a fair bit and I still don't know very much just enough to get by however I really enjoyed learning programming as its a nice thing to know, using eagle however is very boring at times like you say trying to solve a puzzle! it was the drive to finish my poject that kept me going!

Autoroute is just awful however seeing how I do power converters then autoroute isnt very useful to me as its all manually laid out to minimise parasitics

"NORMAL" is just a cycle on the washing machine..

I am certainly not normal! ]:D whatever normal is :D, how many young lads love math? and all things power electronic! :stuck_out_tongue_closed_eyes:

Does anyone want to confirm for me that the black marks are because of no heat control on my iron then I will rest easy!

Does anyone want to confirm for me that the black marks are because of no heat control on my iron then I will rest easy!

It looks to me like the black marks are just rosin. It can be easily removed with some rubbing alcohol and an old toothbrush. A temperature controlled iron is nice to have but a simple iron can give good results with proper technique.