I needed a case for these PWM controllers.

https://www.amazon.com/gp/product/B07GP72BWV

I created it in OnShape. 

You will need:

2x M3heatset inserts

1x M3x8 SHCS

1x M3x6 SHCS

One insert will go in the body to hold down the PCB and the other will be to hold down the lid.

Print Settings: If you want the honeycomb effect for heat dissipation

0 top and bottom walls

25% Honeycomb infill.

Providing STEP files if needed.