I thought I would give another update here for people who haven’t dived in yet to solder an Artemis. With my first board, I did the solder placement by hand. It was pretty ragged, but it worked. For the next board, I used a stencil. For the latest project, I decided to do the solder placement by hand again. I was pretty sure that this board revision would not be the last, so it seemed like a bit of a waste to get a stencil. Plus, it actually takes time to get the stencils aligned and then there is the fact I’m more interested in seeing if the freshly baked board works than cleaning the stencil.
This time around, I learned how to apply the solder better. For all the regular components, I just squeeze solder onto the pads via a syringe. The Artemis pads are too small and too close together for my syringe tip though. What I found works pretty well is to get an exacto knife and put in a brand new #11 blade, the one with the incredibly pointy tip. Squirt a blob of solder from the syringe onto a piece of paper, which you will use as a supply source for doing the pads. Use the tip of the exacto to get a tiny ball of paste on the end. Now, just barely touch the PCB pad with the ball at the end of the exacto. If the ball size is right, it will transfer some of the paste to the pad. If not, get a bigger ball on the end of the tip. It will take a couple trys to get the size of the ball right, but it is easy to replicate once you have it. Once you get going, you just dab and move on to the next pad. I can usually do 2 or three pads before having to re-dip the exacto in the paste supply on the paper. I saved time by not bothering to apply solder to pads I was not using.
It went really well. The next tricky part is placing the Artemis on the board so that you don’t put it off-axis and smear all your lovely solder paste balls. Take a deep breath and just do it.
Everything went OK, right up until I was adjusting the position of another part and bumped the Artemis with my finger. So I removed the Artemis, wiped off the smeared solder paste with a Q-tip, and redid all the bumps. It went even faster the second time. I attached a pic of my solder balls before placing the Artemis. You can see that they are not too bad, but certainly not as perfectly consistent as with a stencil.
I ran the new board through the toaster oven, and then wrote some simple test software to check the continuity of all my IO solder connections. They all turned out perfect. So there you are, hand application of the solder paste is an option if you want.
