Heated Build Platform in 6mm Al

A simple 6mm thick Heated Build Platform. This was designed to make my ToM more reliable. As I have been dialing in the Z height more accurately recently I have encountered issues due to slight warping of the HBP's PCB and have had a few occasions where this has resulted in failed prints, removal of Kapton tape from the HBP surface and damage to the HBP itself. As I increasingly leave the printer to do its thing unsupervised and place it in the hands of others I wanted a more reliable surface to