Shaft straightness and concentricity in process correction

This thesis treats the correction of concentricity and straightness errors of turbine engine shafts produced by Pratt & Whitney Canada. The objectives of the project are to reduce the manufacturing cost of the turbo shafts engine by correcting concentricity and straightness shape errors. The cost reduction results from relieving the tight tolerances on costly operation, as well as improving the quality.; The straightening added to the correction of concentricity already used at PWC consists of the solution studied to correct the shaft shape errors. This process could be easily controlled and will not affect the properties of the shaft and insure that it will be able to support the necessary loads.; The thesis begins with the bibliographical review in which are exposed the various principles and existing equipment able to straighten shafts. In the section stating the project relevance, the various types of errors of form are defined as well as their source and the costs which they generate. The methods and principles of the straightening by plastic deformation created by a press and of straightening by inducing residual stresses are explained.; For straightening by a press, a finite element model helped with the development of a prototype. The tests carried out at the CNRC on the prototype are in agreement with the finite element results.; For the straightening by residual stress, the first developed equipment is the straightening by ultrasound peening. Tests carried out at the CNRC proved that the permanent deflection created is sufficient to straighten shafts, that the circularity and the roughness of the peenend section are degraded and that the process is controllable because an initially eccentric shaft of 0.007" of runout was straightened to a runout below 0.001".; A study was begun on another equipment of straightening by residual stress, straightening by burnishing. For the straightening by burnishing, a prototype as well a finite element model should be developed. Tests similar to those done on the straightening by press and by peening should be carried out.; The optimum straightening process would be a combination of the straightening by a press and the straightening by peening. The straightening by a press could be used only at the beginning of the process because of the residual stress in tension that it generates. The straightening by peening could be employed on the finished shaft to refine the straightening.