Energy Efficiency Analyses of Toolpaths in a Pocket Milling Process

This paper presents an approach to analytically determine the most energy efficient toolpath strategy in mechanical machining. This was achieved by evaluating the electrical energy requirement of the NC codes generated for the zag, zigzag, and rectangular contour toolpath strategies. The analytical method was validated by performing pocket milling on AISI 1018 steel with the considered toolpaths using a 3-axis Takisawa Mac-V3 milling machine. The rectangular contour toolpath was the most efficient in terms of the electrical energy demand of the feed axes and cycle time. Pocket milling with the zigzag toolpath strategy resulted in higher electrical energy demand of the feed axes and cycle time by 2% due to acceleration and deceleration characteristics of the machine tool feed axes execution at corners of the toolpath strategy adopted. Also, the electrical energy demand of the feed axes and cycle time for the zag toolpath were higher by 14% and 8%, respectively, due to the number of tool retracts as a result of the executed toolpath strategy. The experimental validation results showed good agreement with the analytical approach presented in this study. It can be deduced that for sustainable machining, the rectangular contour toolpath should be adopted since it has less tool retractions irrespective of the toolpath strategy adopted for machining. This could further enhance the selection of optimum green parameters by shop floor process engineers for sustainable manufacture of products.