| 摘要 |
#CMT# #/CMT# Fabrication of a hollow component such as a turbine blade with at least one cavity, in which the external profile, the geometry of the cavity and the wall thickness are predetermined, comprises: (a) fabrication of a rough foundry draft with a cavity (C); (b) measuring the thickness of the walls (P) forming the cavity; (c) comparing the measured wall thickness of the draft with the value of the predetermined thickness in order to determine the zones of over-thickness; (d) removal of material by machining the surface of the draft in the zones of over- thickness. #CMT#USE : #/CMT# For fabrication of components such as metal turbine blading, which involve internal cavities with a complex geometry, notably forming cooling circuits, by the lost wax casting technique. #CMT#ADVANTAGE : #/CMT# Allows, by associating machining with the foundry techniques, the fabrication of hollow blades with a dimensional tolerance much lower than for conventional foundry techniques. It allows the production of very thin walls, notably of the order of 0.45 mm or less, without it being necessary to cast a draft with a profile close to the final dimensions. It provides a greater degree of liberty to the conception and an improved reactivity in the innovation phase. It allows the favouring of the conception to cost objective by the choice of a better compromise between the machining and foundry operations. It is possible to produce blades with a minimum amount of scrap. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The figure shows a turbine blade. C : Cavity; P : Wall; R, r : Radii defining blade geometry. #CMT#METALLURGY : #/CMT# The measurement of the wall thickness can be carried out by mechanical feeling or without contact by ultrasonic, Foucault current or tomographic techniques (all claimed). The machining may be carried out by reaming with removal of the shavings, which may be numerically controlled (claimed). |
