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During machining the accumulated residual bulk stresses induced by previous shape forming process steps, such as forging, casting or additive manufacturing and subsequent heat treatment will be released. This may cause undesirable geometric distortions of the final component and thereby high rejection rates and costs. This problem can be reduced by adjusting process-and design parameters. This paper presents a methodology for minimizing machining distortions. The methodology is based on a combination of procedures for prediction of machining distortions, using the Contour method and procedures for adjustment of machining distortions. Practical experiences are discussed and demonstrated using an aerospace component. The methodology should be executed in close cooperation between several actors in the value chain and best results may be achieved by combining several concepts for adjustment of machining distortions. Further research in conjunction with the Contour method, adaptive fixturing and toolpath adjustment is recommended.

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During machining the accumulated bulk stresses induced by previous shape forming process steps, such as forging, casting or additive manufacturing and subsequent heat treatment, will be released and cause undesirable geometry errors on the final component. By considering the residual stresses during process planning a significant improvement in dimensional accuracy can be achieved. This paper presents experiences for prediction of residual stresses for components with complex geometries using the Contour method. Three sectioning procedures have been tested and a cutting strategi using Electric Discharge Machining with slow feed rate and cutting from two sides with final cut in the middle is proposed. Two Finite Element modelling strategies for 3D-models have been tested and a meshing strategy based on extrusion of the geometry from the cut plane is recommended. Further, a procedure to automate the Finite Element meshing of complex structures using the Alpha Shape algorithm is proposed. The ambition is to integrate this algorithm in procedures for automatization of the entire analysis.