| 摘要 |
A thermo-forming machine is described for forming three-dimensional work pieces, having extensive relatively thin surfaces of uniform thickness, from flat sheets of a thermoplastic material. The machine includes one or two molds ( 31, 131 ) movable vertically between a passive lowered position and a raised forming position, a lower, pressurizable sealed chamber ( 14 ) closed at the top by a horizontal reduction plate ( 12 ) having a first and a second aperture ( 12 a , 12 b), spaced horizontally and of a size enabling a mold ( 31, 131 ) to pass through them. First and second counter-frames ( 29, 30 ) each hold a sheet to be formed around the apertures ( 12 a , 12 b) of the reduction plate ( 12 ). Three heating panels ( 16, 17, 22 ) are provided, aligned vertically, spaced from each other and movable horizontally between a first position aligned vertically with the first aperture ( 12 a) and a second position aligned vertically with the second aperture ( 12 b). The upper heating panel ( 16 ) and the intermediate heating panel ( 17 ) are positioned above the reduction plate ( 12 ) for preheating opposite surfaces of a flat sheet supported between these two panels ( 16, 17 ). The lower heating panel ( 22 ) is positioned beneath the reduction plate ( 12 ) for simultaneously heating from beneath another sheet held around one of the apertures ( 12 a , 12 b) and heated from above by the intermediate panel ( 17 ).
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