A Framework for Parameters Planning in Hybrid Milling of Flexible Blades

In the milling of flexible workpieces, like thin-wall blades, cutting force-induced deformation and vibration are great adverse issues that are almost inevitable. Semifinish–finish (SF) hybrid milling is a promising strategy to obtain a high accuracy and quality surface, which separates the object blade into several layers in the radial direction of the blisk, and then for each layer, from blade tip to root, using SF hybrid milling as a cycle to finish the current layer, and then move to the next layer. However, two extra contradictions are introduced in process planning: (1) considering the number of layers: To decrease the machining deformation error, we should increase the number of layers, which however increases the time consumption as well as the number of tool marks because of frequent tool path switching between semifinish and finish; (2) as to the allowance of semifinish: To decrease the machining deformation error, we should increase the allowance in semifinish to enhance stiffness, which however increases tool wear since more material needs to be removed by the tool. To balance the contradictions, this article constructs a framework for parameters planning in SF hybrid milling, in which the allowance, number of layers, as well as lengths of each layer are optimized so that we are able to control the deformation error while maintaining high cutting efficiency. The method is verified by simulation and validation experiments. Compared with traditional nonlayering and uniform layering machining, the maximum deformation error by optimized layering machining is reduced by 76.4% and 48.6%, respectively.