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

by george graves on Thu Feb 17, 2011 9:09 am

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
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It's really hard to convey to people how small this stuff is.
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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.
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I'm a sneaky little bastard.
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Paste laid up. It came out perfect I think - might need to adjust the stencil for the amount, but looks great.
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ready for reflow
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Finished. Almost perfect. A bit too much solder? My 10 mil traces don't look bad either. That's insane.
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Another look at the heel. How's it look?
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by adafruit on Thu Feb 17, 2011 12:55 pm

nice fillet!
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by Alphatronique on Thu Feb 17, 2011 1:58 pm

Hi

nice stencil :mrgreen:

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 ?

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

by skylen on Thu Feb 17, 2011 8:09 pm

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.
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by george graves on Fri Feb 18, 2011 7:56 am

I have a few more tests then I'll do a full write up with parts,how to, and maybe a video.
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by skylen on Fri Feb 18, 2011 10:07 am

OK, I'll definitely be looking forward to that. Thanks!
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by Agent24 on Sun Mar 06, 2011 7:09 pm

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

by RandyHall on Mon Mar 07, 2011 12:05 pm

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

by Philly on Mon Mar 07, 2011 3:32 pm

Im guessing it was etched the same way as copper clad, but with the back of the brass covered.
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by rayshobby on Sun Jan 01, 2012 4:49 pm

Perhaps the process is similar to this one?
http://rayshobby.net/blog/?p=1246
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by xl97 on Wed Nov 21, 2012 11:08 am

bump... (lol)

what ever happened to this 'write up'?? :lol:


looking for hwo the stencil was made too!..

(might be better than ordering a kapton once each time..!!!!)
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by bearmos on Mon Nov 26, 2012 8:50 am

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!
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Re: Check my joints? DIY SMD stencil w/ *pictures*

by adafruit_support_mike on Tue Nov 27, 2012 9:57 pm

*Nice* work.

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

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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.
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