| 摘要 |
A drawing mold has a contoured mold surface receiving a metal sheet thereon. A tensile drawing machine applies a drawing tension to the sheet edges to deform the sheet onto the mold. Heated pressurized air supplied through air holes in the mold surface forms an air cushion between the sheet and the mold, to heat and support the sheet without friction. A forming method includes: a pre-stressing phase of pre-stressing and pre-bending the sheet at room temperature and atmospheric pressure; a heating phase of heating the sheet with the pressurized air at an ele- vated temperature and intermediate elevated pressure; a forming phase of maintaining the temperature and increasing the pressure to support the sheet on the air cushion, and drawing the sheet with the tensile drawing machine; and a cooling phase of cooling the sheet without further deformation, with the air at the inter- mediate pressure and cooled to room temperature.
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