I designed, 3D modeled and fabricated a vacuform machine.  The frame is made out of aluminum unistrut and uses all of the unistrut accessories to make it adjustable with it's max size at 3' x 3'.  The frame glides on four aluminum 2" x 2" square posts utilizing a shuttle with ball bearings.  Along side shuttles and so one person can lift this big frame, a counter weight system was built in using airline cable, pulleys and PVC pipes filled with lead fishing line weights.  Lastly the vacuum system is made up of a vacuum pump and two 11 gallon air tanks.  Please see the page with the 3D printed platen systems.