An impeller is normally manufactured through several processes such as turning for the contour profiling, drilling for a 3-axis key-hole, and milling for the blade and hub machining. A series of machining strategies are required to determine the variables and parameters of the machining processes, including the machining area partitioning, tool selection, cutting condition specification, and tool path patterns. Considerable time is expended in building these strategies, especially in the rough cut planning involved in the rough machining area partitioning, and machining data production and verification. The machining time and surface quality are the two major factors in the rough cutting planning. Thus, this study presents a hybrid rough cut machining plan for manufacturing an impeller which combines 3-axis and 5-axis numerical controlled (NC) machining based on the cutting volume and tool diameter. In this plan, 3-axis NC machining on unit machining regions (UMRs) is first tried in order to significantly reduce the overall machining time, followed by the 5-axis machining on the last layer of each UMR to secure the required surface quality for the finish-cut. A simulation study for a specific impeller is presented to compare the conventional 5-axis rough cut time with the proposed one.
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