EXPERIMENTAL AND ANALYTICAL STUDIES ON THE DETERMINATION OF HOLE QUALITY IN DRY DRILLING OF GFRP COMPOSITES

Abstract

In this investigation nonlaminated Glass Fiber Reinforced Plastic (GFRP) composite rods made by pultrusion method with high fiber weight fraction was drilled with a special geometry coated carbide drill. The ovality of the drilled holes were measured using CMM. Taguchi’s orthogonal array and analysis of variance (ANOVA) were employed to study the influence of process parameters such as feed and spindle speed on ovality. The optimum level of process parameters towards minimum ovality were obtained to achieve defect controlled drilling of pultruded GFRP composite rods. Correlation for ovality with process parameters were established using a statistical software MINITAB 16 and found not to be fit. The influence of feed was insignificant and that of speed was significant on ovality of the drilled holes. The optimal process parameter levels within the range examined was identified as 0.05 mm/rev feed and 1000 rpm speed for drilling pultruded GFRP composite rods using 10 mm ratio drill. The influence of process parameters on hole quality in nonlaminated composite rods differs from that of in laminated composites.