Multiple electrode guide block cast in plastic - suitable for electrochemical drilling of coolant holes in turbine blades

摘要

A guide block for electrodes employed in electrochemical drilling, is mfd. by (a) inserting several rod cores in specific positions in the walls of a mould; (b) casting a plastic in the mould to form the block; (c) removing the cores from the block and the mould-walls; (d) extracting the block from the mould; (e) inserting dielectric tubes in the holes made by the cores, the tubes being used to guide the electrodes. The mould walls are pref. fixed to a base plate carrying a threaded insert which forms part of the cast block, the insert then being used to mount the guide block in the drilling machine. The block is used in e.g. drilling coolant holes in turbine blades. A row of non-parallel holes can be simultaneously drilled in the blades.