An experimental study on out-of-roundness and material erosion rate during wire spark erosion turning of titanium cylindrical bars

This article presents an experimental investigation conducted on wire spark erosion turning of Titanium grade 5 miniature cylindrical bars. Two main output parameters i.e. roundness deviation, a type of form error, as an indicator of product quality and material erosion rate as an indicator of productivity, have been focused to measure the success of the machining process. A total of seventeen experiments with two replications based on Box-Behnken design (BBD) of the response surface methodology (RSM) were performed to identify the influence of spark duration ‘T_on’, servo voltage ‘S_V’, and depth of cut ‘DOC’ on roundness deviation ‘DR’ and material erosion rate ‘MER’. Grey relational analysis (GRA) based multi-response optimization was carried out to determine the optimum turning condition of WSET with the objectives to minimize roundness deviation and maximize material erosion rate. WSET of Titanium at optimum process parameters resulted in the best values of roundness deviation 15.51 μm and material erosion rate 9.35 mm³/min. The results of validation experiments are much closer to the optimum values of DR and MER with <5% and 2% differences, respectively. Surface morphology investigation confirmed that the surface generated by WSET is fit and suitable for many applications. The results of this work are better than the previous studies and further useful to the researchers for the advanced fabrication of miniature products from difficult-to-machine materials like Titanium.