Very Large Raspberry Pi Cluster - Part I

I am building a very large Raspberry Pi Cluster and I'm going to document the process here. My goal is to post once a week until it's complete and shows up at Oracle Code One in San Francisco  September 2019.  Thus far an unimaginable amount of work has been put into this project to determine if it's even viable. We think it's viable so I'm going to start talking about it. There may be some mistakes. No, there will be some mistakes. Hopefully I won't make too many of them.

For the first taste, here is a rendering of a 2U rack that will hold 20 Raspberry Pi Model 3B+. I've printed out about 50 versions of this and this packs the most in while still allowing heat dissipation and still being serviceable in a standard server rack.

Disclaimer: The Raspberry Pi model is one I found on the Fusion 360 store thing. The rest is rendered by my own mad modeling skills.

Now that I've modeled this up and printed it I'm going back to the drawing board. It takes 14 hours to print the orange part which holds half of the Pi rack using an Ultimaker S5 with a .08mm nozzle 10% infield and .2 layer height. The Pi snaps in nicely but there are too many issues and this part needs to be nearly perfect.