Surface Mount & Stencils

So, this morning I did my first IMU board with a stencil I had ordered from Pololu. All I can say is, wow! What a huge difference. It took about 2 minutes to get the stencil aligned, and about 30 seconds to spread the solder paste (I used a razor blade since I couldn't find a decent stainless steel spatula with a fine enough blade). The solder paste came out absolutely perfect when I peeled off the stencil, and I simply dropped the ATmega168 onto the pads, put all the other parts on, and stuck the board in the reflow oven.

When it came out, it looked perfect. I soldered on the bus connector and the other bottom components, connected the programmer, and powered it up. For the first time with an MLF-32 chip, everything worked perfectly (no solder bridges). I programmed it with the correct fuses and the IMU code, and it works great!

I've done a few of these boards by hand before, and let me tell you, trying to get solder paste onto pads that are 0.5mm apart is non-trivial. Using a stencil makes it trivial...

Big kudos to Jan at Pololu, and if you've got a lot of fine pitch surface mount stuff to do, I would strongly recommend looking into their laser cut stencils.