Check my joints? DIY SMD stencil w/ *pictures*

[george graves]

So...I made my own SMD stencil - all from thing I found at the hardware store. I'll be doing a full (video?)write up once I iron out some kinks - so bear with me.

Pictures are below - but before you forget - please let me know what you think of my joints. It looks like there might be a tad too much solder? Please let me know what you think of it. Too much on the toe?

Some surface mount stuff to test




It's really hard to convey to people how small this stuff is.


Some test boards - they do nothing. Just testing pad size and the effects of surface tension, pad width and trace location on centering parts during reflow. Trying different pad sizes, ect. And I hope that I can sneak a trace between the pads of an 0805 - that would be nice.


I'm a sneaky little bastard.


Paste laid up. It came out perfect I think - might need to adjust the stencil for the amount, but looks great.




ready for reflow


Finished. Almost perfect. A bit too much solder? My 10 mil traces don't look bad either. That's insane.


Another look at the heel. How's it look?

[adafruit]

nice fillet!

[Alphatronique]

Hi

nice stencil

solder past volume was ok for 1.27 mm soic and 0805
you may will need to reduce it for do finer pitch and use 5mil think brass

did you etch brass whit ferric chloride ?

Best regard

[skylen]

Wow, very nice work. I would love to be able to achieve that quality in my lab. Can you comment on the following:

• What is your PCB etching process (impressive quality at 10 mil traces!) -- did you use toner transfer? What kind of paper? What make/model of printer? I have used the Pulsar Pro FX Toner Transfer Paper/GreenTRF which seemed a great improvement in consistency from using photo paper. However, I'm having toner density and quality problems with my laser printers that are giving me all kinds of problems right now.
• How you made the stencil? (what did you etch that you found at the hardware store? how did you etch it?)
• What's your reflow process? Toaster over? Skillet/hot plate? I recently got a cheap hot plate to try out.

[george graves]

I have a few more tests then I'll do a full write up with parts,how to, and maybe a video.

[skylen]

OK, I'll definitely be looking forward to that. Thanks!

[Agent24]

These look very nice

I have yet to try anything like this so far but its nice to know with some care you can get good results like this.

Currently the smallest traces I have done are 20mil (or 0.5mm), but they have come out near-perfect so I think even 10mil shouldn't have much of a problem for me.

I see yours do have wavy edges, do you know what caused this?

[RandyHall]

I have a few more tests then I'll do a full write up with parts,how to, and maybe a video.

I definitely want to see how the stencil was made. It's sick how well it worked.

--R

[Philly]

Im guessing it was etched the same way as copper clad, but with the back of the brass covered.

[rayshobby]

Perhaps the process is similar to this one?
http://rayshobby.net/blog/?p=1246

[xl97]

bump... (lol)

what ever happened to this 'write up'??


looking for hwo the stencil was made too!..

(might be better than ordering a kapton once each time..!!!!)

[bearmos]

Nice work. The heals of the IC's look perfect, although I do agree the toe of one may have a little too much solder on it (but only in one of the shots). In the rest of the pics the toes look fine.

Also curious as to what methods you're using for etching (first guess is photo transfer for the PCB from the looks of the traces) - it certainly looks more respectable than anything I've done with photo transfer!

[adafruit_support_mike]

*Nice* work.

FWIW, I've gotten two 10 mil traces between the pads of an 0805 without too much pain:


It isn't nearly as pretty as yours since it's hand-soldered, but it is a toner transfer job. The trick is to leave 50-60 mil between the 0805 pads.