Drilling study on lightweight structural Mg/SiC composite for defence applications

Abstract

Heat energy generated during machining has been found to have a greater influence on determining the machinability of the materials. In this work, magnesium-based silicon carbide composite, which has been identified as a suitable lightweight application material, is prepared with the weight ratio of 90:10 by a stir casting process. Conventionally available HSS drill tools with different diameters of 4, 6 and 8 mm are used to perform the drilling operations with governing parameters of spindle speed, feed rate and constant depth of cut. Thermal image camera of the FLIR E60 series is used to measure the temperature variation in the cutting zone at different operating conditions. The influences of machining temperature on chip morphology, tool wear and surface profile of the machined samples are investigated. Spindle speed has been found to have a significant effect on machining temperature. When spindle speed increases, the diameter of drill tool increases the tool wear and surface profile, respectively. Both abrasion and adhesive type of wears are observed in the drill tool. Further, change from abrasion to adhesive wear is noticed with the increase of the diameter of the drill tool. Surface plots are drawn with respect to the interaction of governing parameters along with the working temperatures obtained under different machining conditions. Keywords: Magnesium, SiC, Drilling, Thermal effect, Chip morphology, Tool wear