I chose VIM3 to be my daily SBC drive, so I want it to be quiet. I tried a 40x30x5mm heatsink for RPi4, but not satisfied with the result, I decided to make one. I don’t have CNC machine, so I bought a small hacksaw and a pack of files from Walmart for less than $10.
The raw 150x70x10mm heatsink is from Amazon, for $11. Here is the size comparison:
At first wanted to be lazy, just cut a 70x30mm piece and sticked it on with thermal tape, but it doesn’t feel secured, one reason is the chips are not even, I have to shim them with little copper pads ($10 for 100 pieces at Amazon), there are too many moving parts in the mix.
So I decided to spend a little more time make it full blown. In order to make the heatsink contact with the chips, I hand made a extruded block with 1x1/4" 6061 aluminum flat bar (I was able to find a 4" piece for $1.68 at local metal supplier, the silver one in the picture above). I cut off a corner to avoid the tall components, and bonded it to the heatsink with Arctic thermal epoxy. To make the block fully contact with the chips, I put some 1.5mm thermal pads in between. The thermal pads are squeezable, which helps to adjust the pressure since there are no springs on the M2 standoffs.
Because the WiFi chip is covered up by the heatsink, I made it a little longer so that I could install two “mushroom” antenna on the heatsink.
Now I’m waiting for Linux 5.10 kernel and the Mali GPU support to push this little computer to its peak.
The copper shims are not used after all: