This week, we had to characterize the design rules for our Shopbot, mill a circuit board and then stuff it.
Making my first PCB board proved to be a huge accomplishment (at least personally)! I used the SAMD11C hello world board provided on the website as a base. The bits came in 1/32 and 1/64 sizes. The bits are extremely fragile, so I tried to be very careful. Then, I adhered the PCB using double-stick tape. From this point onward, I had to make sure to count to five before doing anything, because if I opened the hood too quickly after initiating machine action, I'd have to reset the machine.
I next had to zero the machine and upload the design file. There was the interior file (which would be done first) and then the exterior. Even though I didn't really understand the purpose of mods up to this point, I'm glad that it was part of the work flow. Once I set parameters in mods, a lot goes on under the hood to get the Shopbot to print.
Final milling stages (VERY LOUD)
After I cut out the board, I laid out all the pieces that I would be working with. There was the microcontroller, voltage regulator, resistors, connector, capacitor, and power pins. These components are TINY -- which is hard to appreciate until you start trying to solder.
My small board next to even smaller components
I tried to incorporate everything that I had been taught -- making sure the iron was cleaned, using flux, etc. But I think everyone has their own style. Some people used the microscope, others relied on their eyesight. I opted to use the microscope. Then the choice of tweezers was another factor. Some curved at the end while others were straight. But by far the biggest choice was leaded or unleaded solder. I really tried to use the unleaded, but it was often hard to get it to melt. My technique was also less than ideal, so I'm sure that was also a factor.
Soldering under the microscope
It looked like the components or the board was sweating. I think they may have been from the double-sided tape (I tried to clean up dust on the board with tape, so adhesive was probably left on). I don't think it affected anything. You can also seem some dark spots on the baord, from when I had to redo components (if you leave the iron on too long, the color starts to shift due to temperature).
Overall, I am happy with the finished product.
My first board!
