knee joint 7 will have the amount of knee rotation as determined by the prosthetist the thermoplastic sheet cut to the appropriate size is placed and heated in a wide oven at the appropriate forming temperature the positive mold is placed horizontally in a vacuum fixture for thermoforming the plastic under negative pressure the thermoplastic is removed from the oven when the plastic is ready and moldable the thermoplastic sheet is applied to the positive mold a seam is formed along the lower aspect of the positive mold the thermoplastic is pinched along the seam and held until the vacuum pulls in the plastic into all the undercuts so that there are no air voids after the thermoplastic cools down the plastic is sanded down on top of the lock mechanism fastener screw 18 the fastener screw 18 is then removed the fabrication block 108 is trimmed out with a cast cutter and sanding router and the fabrication block is removed the thermoplastic socket is removed from the positive mold using compressed air or the mold is broken out of the socket with a pneumatic chisel or other suitable method is employed the thermoplastic socket material is sanded down to the top of the set screws 30 using a sanding router the set screws 30 are removed with a hex wrench and the fastener screws 34 with washers 32 are installed and tightened in place of the set screws 30 the edges of the.