An experimental and statistical study on the effect of drill geometries on force and hole quality in drilling of glass fibre reinforced plastic

Aircraft manufacturing involves drilling of large number of holes, in which the joint can be critically affected by the quality of the hole. Effect of drill geometry on drilling of glass/epoxy laminates using twist, Zhirov and Multifaceted Drills (MFD), has been studied. The thrust force and hole quality were compared for each drill geometry. Zhirov drill cuts the hole with less force and best surface finish. MFD produces less delamination when compared with the other geometries. ANOVA was used to study the effect of drill geometries, spindle speed, and feed rate on thrust force, surface finish and delamination factor.