| 摘要 |
PURPOSE:To improve the characteristics of an element due to enhanced accuracy of hole dimension by punching to a specific thickness of a metal plate on which electron beams holes are to be provided, pressing it to recover the original state, and punching to form desired holes. CONSTITUTION:A metal plate 81 is punched using an outline punching die 821, stopper 831, and outline punching punch 841 to the thickness of 2/3 of the plate, and a pressure is applied on both sides of the metal plate 81 to restore the punched portion nearly to the original state. Then the metal plate 81 is punched using both side hole punching die 822, punches 842, and a stopper 832 to the thickness of 2/3 of the plate, and a pressure applied on both sides of the plate to move the punched portions nearly to the original state. Then three holes are punched completely using a central hole punching punch 843 and punches 842. Thus holes with high accuracy and without the deformations such as swelling and tilting and change of thickness can be formed, and the enlargement of an electron lens diameter and improvement of focus quality of an electron gun can be attained. |
