| 摘要 |
PURPOSE:To easily form the shadow mask of high accuracy by the residual stress caused by the temp. difference by forming spherically by raising the temp. at the projecting face forming side of the plate like shadow mask of high tensile steel more than the temp. at the recessed face forming side. CONSTITUTION:The temp. difference is provided in the space with the face of a punch 14 side by heating the face at the knockout 12 side of the plate like shadow mask 10 which is pinched by heating bodies 17, 18 to the prescribed temp. by pinching the peripheral part thereof by the knockout 12 and the blank holder 16 which advances by linking with the punch 14 by locating the plate like shadow mask 10. In the base, the advanced punch 14 is located at the position where the center part of a forming face 13 comes into contact with approximately the shadow mask 10. The center part of the shadow mask 10 is then formed by bulging it spherically with each forming face 11, 13 of the knockout 12 and punch 14 by advancing the punch 14 further, and the skirt part is formed on the peripheral side part thereof as well.
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