| 摘要 |
1281532 Making turbine blades; composite casting processes ROLLS-ROYCE Ltd 14 Nov 1969 [15 Nov 1968] 54188/68 Headings B3A and B3F A method of making a mounting for holding a workpiece, e.g. a gas turbine blade, during machining operations comprises applying a settable coating 4 to a portion 2 of the workpiece and casting a block 5 of material about the coating when set, the cast material being solid at room temperature and the coating remaining stable at least up to the melting temperature of the cast material and comprising a grit in a binder which is soluble in a solvent non-corrosive to the workpiece. The grit may be sand, aluminium oxide or silicon oxide of particle size between 100 and 220 B.S. mesh, the binder polyvinyl alcohol, cellulose-based materials, polyvinyl butyral or poly-methyl methacrylate, and the cast material a low melting point alloy. As shown, the block 5 is cast about the aerofoil section 2 of a gas turbine blade from which it is removed after the machining operation. |
