Model for the prediction and optimization of flaws and material removal rate during machining of shafts in Ghana

Abstract

The main aim of the study was to develop a prediction model for the flaws and the material removal rate and optimize the cutting conditions during machining using factorial design techniques. A  2³ experimental design method was used to generate predictive models and plots. The results showed that the feed was the most influencing factor of resistivity (as a measure of intensity and number of flaws) followed by the spindle speed. Depth of cut posed an insignificant influence on resistivity. Similarly, the feed had the highest influence on material removal rate (MRR) followed by depth of cut, and lastly, the spindle speed. The optimal cutting conditions for minimum resistivity was found to be at lower feed (0.2 mm/rev), at higher speed (500 rpm) and at lower depth of cut (1 mm), producing a minimum value of 87.65 µΩ mm resistivity and that of MRR was found to be at lower feed (0.2 mm/rev), higher speed (500rmp ) and at higher depth of cut (4 mm) producing a minimum value of  83.25mm³s^-1  material removal rate. That is the rate of flaw development and/or propagation, and material removal rate during machining of a shaft in Ghanaian manufacturing industries could be modeled and optimized. It can be concluded that there is change in resistivity of materials which can be attributed to increase in the number and intensity of flaws during machining of a shaft and this is influenced by cutting conditions, especially, the feed rate. It is therefore recommended that a feed rate of 0.2mm/rev, a speed of 500 rpm and depth of cut of 1 mm which will give the minimum flaws induced during machining be used.