Any tips for 4-layer boards?

[Byte_Butcher]

UPS brought my boards yesterday!
I think I'm starting to really enjoy working with surface mount devices...
There's a certain pleasure in being able to put 63 parts (only 61 loaded in this photo), plus room for connections to the outside world (LCD display, sensors, power, etc) on only 4.5 square inches (29 sq cm) of real estate.

I loaded it up and ran it through the oven last night. Dunno if it WORKS yet, but it *looks* OK so far.



Here's a close up of the solder job. It's hard to resist the temptation to put too much solder on the pads. Just the tiniest bit is plenty. These look pretty good.



Big fun!

steve

[rsocor01]

Very nice!!!

Where did you buy your stencil from?

Robert

[Byte_Butcher]

Mmmm... if you mean a solder paste stencil, I've never used one. Yet...

For the small runs of boards I do, I apply paste by hand with a pointy tool under a magnifying lens. It took me less than 10 minutes to apply solder paste to all the pads on that board. (that includes going to the fridge and back for another beer). I'm hoping to be doing some larger runs of boards soon, so paste masks will become a necessity for me sooner or later (I hope).

I'd love to hear folks experiences with getting stencils made (cheaply)...


steve

[dhouston]

I've done them manually as you do and I've used a stencil. The thickness of the stencil controls the amount of paste applied. The stencil is preferred but for small parts and small quantities I still use manual methods. Here's a good source for stencils.

• http://www.quickstencil.com/prototype-stencil-kit.aspx

I've also seen less expensive mylar stencils but have not tried them.

• http://www.pololu.com/catalog/product/446

[rsocor01]

Wow, I didn't know you could make it without a stencil. But you are right, for a prototype why spending more money. I might try it in the future.

I have soldered 44-lead TQFP pics like the one you have in your pictures and I usually get my plastic stencils from www.ohararp.com. They are inexpensive and do the job. I have also tried pololu.com that was mentioned by dhouston. But for a bigger production I would recomend you panelizing your boards and using www.stencilsunlimited.com.

Robert

[Byte_Butcher]

Thanks Dave and Robert for the links!

I've bought from stencilsunlimited before.. that's where I got my solder paste and flux.

I took a quick look at the ohararp, pololo, and quickstencil sites and they got bookmarked for future reference. Sooner or later stencils will become a necessity for me.

Sure does make me drool to look at all the fancy laser cutters for making stencils, the PCB routers for making boards, and all the fancy reflow ovens and pick & place machines that are available now. All I need is a bunch of money. sigh...


steve