I decided a while ago to build a vacuum former. The first stage is to build a vacuum plenums hown below.
It is 360mm x 560mm which will take a sheet 400mm x 600mm once clipped to a frame which I’ll fabricate out of 12mm aluminium C channel.
Its made out of 19mm melteca (MDF). I’ve milled to a depth of 12mm (using a 12mm HSS wood router). 500mm/min, 3 passes @ 4mm per pass. I possibly could have routed faster/deeper, however the cheap router bit I was using on the first go burnt out.
Here is a picture of the platen after milling on my CNC 6040 Chinese milling machine
