Effect of drilling parameters on mechanical strength in drilling glass fibre reinforced plastic

The damage generated during the drilling of Glass Fibre Reinforced Plastics (GFRP) is detrimental for the mechanical behaviour of the composite structure. This work is focused on analysing the influence of drilling parameters (spindle speed and feed) on the strength of the GFR woven fabric laminates and further to study the residual stress distribution around the hole after drilling. Holes were drilled at the centre of the specimens in a CNC machining centre using 6 mm diameter micrograin carbide drill for various spindle speeds (1000-4000 rpm) and feed rates (0.02, 0.06, 0.10 and 0.20 rev/min). Degree of damage depends on the feed rate and spindle speed. Experimental results indicate that failure strength and stress concentration are related to the drilling parameters and a drilling parameter (3000 rpm and 0.02 mm/rev), which gives better mechanical strength.