Week 3: PCB Milling and Stuffing


This week's assignment involved no design... just plain following instructions. It turned out to be the most frustrating week so far! At first, nothing went right... the milling machine in the architecture lab was very fussy, and the computer ridiculously slow. Here is a chronicle of my mistakes:

Attempt 1: The board wasn't flat on the bed, though I did check for tape and debris... I think it was because the sacrifical layer in that area was so chewed up. This caused the lower right corner of the board not to be milled at all.
Attempt 2: So I re-zero'ed the z and sent it again for a 2nd print but it still didn't go deep enough in that area!

Attempt 1 and 2 Board

Attempt 3: Because some of the lines were getting too thin I got a new piece and positioned it at approx. x:10 and y: 50. It started great... and then I accidentally input CONTROL C (I was trying to copy something in another window) and that apparently kills the operation. WOE IS ME.
Attempt 4: So we re-zero'd again and resent the rml file. The bit broke at some point during this job, and my whole morning was completely wasted. Not in a good mood at this point.

Attempts 3 and 4 Board

Attempt 5: I went to the CBA lab to mill. The milling machine is so much better there. It was 1. not slow and 2. cut better. My first attempt there was thwarted by the cut not being deep enough... I guess I suck at setting the Z.
Attempt 6: So I started a new plate, and set the depth at -0.125 (instead of -0.1) and VOILA!

6th attempt is successful.
Beautiful... I still managed to break another bit, the 1/32" one, in fact, while cutting out the board. Oops.


I have welded steel before, but never soldered. Soldering is delicate. At first it was again extremely frustrating! I was too impatient to practice one something else, so I started right away on my preciously milled board. Thankfully the TA and my soldering partner were patient and helpful and I got the hang of it by the end. In fact I liked it so much I started soldering on the etched boards as well:

Etched board half-way soldered... ran out of processors so I stopped.

To give people unfamiliar with PCB's an idea of how small this is:


At first I didn't think it was showing up so I re-flowed the solder at the delicate USB connection. It turns out I didn't know what I was looking for, and it does show up as "FABisp". SUCCESS!!!