| 摘要 |
A firtree profile, for example on a component of a gas turbine engine, is formed in a two-stage process. In one stage, an intermediate profile is formed, for example by a mechanical machining operation such as grinding. Subsequently, in a second stage, loaded flanks 16, 18 of the profile are formed by an electric discharge machining operation performed on the intermediate profile. Alternatively, the electric discharge machining operation may be performed first to create the intermediate profile, and subsequently transition regions, such as fillets 24, 28, may be formed in a mechanical or chemical material removing operation. In the resulting profile, surfaces, such as the loaded flanks 16, 18, which must be finished to tight tolerances, but which are subjected to relatively low bending stresses, are formed by the electric discharge machining operation, which leaves a re-cast layer 36. In regions subjected to higher bending stress, such as regions 34 of the fillets 26, 28, are formed by mechanical or chemical metal removal techniques, and so do not have the re-cast layer 36. |
