An automated technique for finishing gas turbine engine blades or vanes by generating a bespoke tooling path for each blade or vane. The bespoke tooling path is generated by scanning the aerofoil surface to generate a 3-D electronic representation of the surface. The 3-D electronic surface is then analyzed to identify imperfections or defects, and then a machining path a generated through which the imperfections can be removed. The machining path is determined so as to smoothly blend the surface back to the underlying surface where the imperfections had been present. In this way, the resulting aerofoil, once machined, has optimized aerodynamic performance.

A wire electrical discharge machine machines a workpiece so as to have different machined shapes on a top surface and a bottom surface of the workpiece. The wire electrical discharge machine includes: a distance measuring sensor for moving within a machining area of the wire electrical discharge machine and measuring a distance between the distance measuring sensor and an object to be measured; and a vertical position calculating unit for calculating a distance between a reference surface and the top surface and a distance between the reference surface and the bottom surface, from a distance between the reference surface and the distance measuring sensor, a distance between the top surface and the distance measuring sensor, and a distance between the bottom surface and the distance measuring sensor, measured by the distance measuring sensor.

A wire electrical discharge machine machines a workpiece so as to have different machined shapes on a top surface and a bottom surface of the workpiece. The wire electrical discharge machine includes: a distance measuring sensor for moving within a machining area of the wire electrical discharge machine and measuring a distance between the distance measuring sensor and an object to be measured; and a vertical position calculating unit for calculating a distance between a reference surface and the top surface and a distance between the reference surface and the bottom surface, from a distance between the reference surface and the distance measuring sensor, a distance between the top surface and the distance measuring sensor, and a distance between the bottom surface and the distance measuring sensor, measured by the distance measuring sensor.