Evaluation of Delamination in Drilling Rice Husk Reinforced Polyester Composites

Abstract

Delamination is recognized as one of the most critical defects that can result from the machining composites. Delamination has been a major form of failure in drilled composite materials due to the composites lack of strength in the drilling direction, which results in poor surface finish, reduction in bearing strength, reduction in structural integrity and ultimately poor performance of the composite. Currently, most of the major research reported delamination address specific of machining fiber glass, graphite fiber or carbon fiber reinforced polymer composites. It is not yet clear how different drilling parameters affect the machinability of natural fiber reinforced polymer composite materials and quality of drilled holes. This paper report the investigation in drilling holes on natural fibre reinforced polyester composites and evaluate its hole quality by measuring delamination. Three different type of drill: twist 118o drill, brad drill and end mill were used. Drilling process is carried out for three spindle speed (1500 rpm, 2000 rpm and 2500 rpm) and three feed rate (0.1 mm/rev, 0.15 mm/rev and 0.2 mm/rev). Brad drill experienced higher delamination values compared to twist and end mill. Increasing of feed rate and spindle speed also caused a relevant increase in the delamination values. It is found that Rice husk reinforced polyester composites delamination value is lower when compared to the glass fiber reinforced polymer.