| 摘要 |
856,983. Making turbine blades; drilling by spark erosion. ROLLS-ROYCE Ltd. June 10, 1959 [June 18, 1958], No. 19565/58. Classes 83 (2) and 83 (4). One or more transverse holes are formed in the wall of a longitudinal boring 18, Fig. 2, of a metal article, particularly a gas-turbine blade, by spark erosion using an electrode 15 with a longitudinal portion 16 and one or more lateral projections 17. The transverse holes may be used to interconnect cooling passages 18, 19 in a turbine blade as described in Specification 856,674. For initial setting the electrode, an indicator lamp 23 and battery 22 are used to ensure that the electrode is out of contact with the wall of the boring. A separate D.C. supply is used for the erosion during which the replaceable copper or brass electrode 15 is fed downwardly and is vibrated longitudinally by an electromagnetic vibrator. Dielectric fluid is fed through a capillary bore in the electrode and the operation may take place in a bath of dielectric fluid such as paraffin. The blade is mounted on a table 11, Fig. 1 (not shown), capable of horizontal movement in two directions. |
