SMD Soldering Practice
Each column is set up with three sizes of 0-Ohm resistors (1206, 0603, and 0402 for a challenge) with each column having a distinct varying feature: how it connects to ground.
Looking left to right, the first column simply uses a trace to a common via that connects the ground for each. The middle one connects the ground end of the resistor to a ground plane directly with no thermal relief in the solder pad features. The rightmost column is similar to the middle column, but does have a thermal relief in the ground connection. Finally, the IC package pin squares were for practicing applying solder across multiple pads at once and using a solder braid/wick to separate the solder bridge(s) you would likely create in this process.
These are to be soldered to the best of each student’s ability without the aid of a microscope (likely because there certainly weren’t enough microscopes for the whole lab class to all use at once). The lab assignment specifically said to maybe try one 0402 resistor, but it wasn’t necessary if you couldn’t do it.
I’ve had prior practice in soldering SMD components in all three of these sizes (especially 0603 and 0402s) with my work over at Last Gameboard, but for the most part I utilized a small digital microscope for certainty. This was the first time I’d attempted to solder any of these without a microscope, and I can report that I only had one resistor fail (the end cap came off, if I recall, leaving me with nothing to solder to) and just 2-3 others with an open connection - all of these were in the center column with no thermal relief features.
Soldering/tinning the IC package footprints went very well, and I actually had to intentionally add too much solder in order to create bridges - otherwise, they all tinned beautifully!
Walking away from this lab project, I wasn’t sure whether or not to be impressed or slightly terrified that I was able to solder 0402 resistors without a microscope…
