Since I have a few open air 12x gpu mining rigs, I figured out a cheap and easy way to stack them.  So If you have these open frame cases and are looking to stack them.

They're thick and 60mm tall and are designed to rest on top and bottom cross bars while inserted over the corner edge (29mm deep) with  small 0.5mm gap to keep things tight. if your corners are bent, fix them first before using them.

Bambu X1C/Orca slicer 0.20 Strength default settings 

6 walls thick

5 walls top/bottom

0.2 Layer height

25%+ infill

Precise walls will help

Speed:  I used Bambu PETG-CF and default setting and set the speed to 60mm/s with the AUX parts fan off and lid closed to maintain 40+C chamber temps to help with the layer bonding.   And its up to you if prefer annealing afterwards.  

Please use the correct filament. PLA may work but will weaken with time & heat . Use PETG or PETG-CF or something stronger.

A fully loaded rig weight is over 80lbs with 12x 3070s and three 1500Watt power supply and combined with the heat will kill PLA. 

Total filament: 210g

Print time: 6+Hours