Machining Part Program Optimization through anAdvanced Multidisciplinary Procedure

In the production of aerospace engine components, metal cutting processes are characterized by a strong demand for increased productivity that does not compromise the high quality of the product. The antithesis stands in the fact that it is necessary to maximize the feed rate and cutting velocity in order to reduce the processing time without compromising the quality of the worked component. In aerospace machining applications on hard-cut materials like: nickel based alloys, titanium alloys, etc, it is fundamental to keep under control the local cutting zone phenomena in order to assure the final product quality. The machining process design development can be summarized by the following steps: definition and verification of the Part Program (PP) through dedicated CAD–CAM software applications, post processing of the produced PP, CNC machine simulation and physical tryout. A further development of this procedure foresees the application of the kinematic optimization to improve the cutting process with a significant time reduction through the optimization of material removal along tool path. In this study a new multidisciplinary procedure is proposed. The aim of the authors is to modify the operation parameters set in the already kinematically optimized PP according to the constraints arising from the physical nature of the cutting process obtained by FEA. A milling operation that include the use of rough and finish tools related to an aeronautical engine component made by Inconel 718 has been chosen to test the developed methodology. The aims of the procedure is to minimize the execution time of the cutting process in compliance to physical micro-scale constraints (maximum admissible cutting edge temperature and maximum admissible Cutting Forces).This foresees the integration of the CAM softwares: Vericut for tool-path verification and Optipath for kinematic optimization of the given PP in the iSIGHT model. The procedure automatically extracts the values of feed and speed in all the blocks of the PP, which have been kinematically optimized, to verify if they respect upper limits (previously set) of: analyzed responses. In the PP blocks where the physical constraints are violated, a Pointer algorithm it has been used to automatically identify the optimal set of the process parameters within the defined design space of the RSM in order to respect the required physical constraints. The new set of process parameters has been updated into the blocks of the analyzed PP.