Patent ID: 7950283

Claim:
A method of predicting deformation of a workpiece that will be subjected to machining, liable to cause deformation of the workpiece through release of residual stresses in the workpiece, which method comprises: a. emitting a beam of ultrasound waves onto a surface of the workpiece, the beam being directed in such a way that a longitudinal wave is propagated in a given direction under the surface of the workpiece and substantially parallel to the surface, b. positioning at least one transducer in receive mode on the surface of the workpiece to receive a subsurface longitudinal wave that has been propagated, c. measuring a propagation velocity of the subsurface longitudinal wave, and d. performing steps a to c in two different regions of the workpiece, a first region being sensitive to residual stresses and a second region being somewhat insensitive to residual stresses, then calculating a difference in propagation velocity between a velocity measured in the first region and a velocity measured in the second region and from the difference, deducing a deformation that will result from machining the first region of the workpiece.