| 摘要 |
1,145,611. Removing metal by high energy beams. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 5 April, 1967 [8 April, 1966], No. 15662/67. Headings B3A and B3V. In a method of piercing a hole 11 in a workpiece 9 by a high energy beam 21, the surface of the workpiece in the vicinity of the hole is provided with a covering layer 15 which is later removed. This layer prevents damage to the hole near the surface. The layer 15 may be of refractory metal such as tungsten and has a spacer 17 formed around the hole to be pierced. Alternatively a separate spacer ring may be used. An electron beam 13 first pierces a hole in the layer 15 and then the centre part of the beam pierces the hole 11 in the workpiece. The beam may be pulsed. After piercing, the layer is removed and the metal workpiece (51), Fig. 5 (not shown), may be then electroplated with copper (55). In another embodiment, Fig. 1, a workpiece (1) of nickel is provided before piercing with a thin layer of copper (5). Subsequently the layer is removed by grinding or etching. Before grinding the hole may be filled with wax which is later removed by melting or by a solvent. For piercing large numbers of holes, the beam may be controlled by a programmed device. The hole may be of circular or elongated cross-section and may extend only partly through the workpiece. The workpiece may be an electrode for an electron tube, or a diaphragm for a mass spectrograph or an electron microscope. Reference is also made to a LASER beam. |
