MACHINABILITY OF SOME FIBER-REINFORCED THERMOSET AND THERMOPLASTICS IN DRILLING

ABSTRACT Polymer-based composite materials are the major candidates for substitution for conventional materials in industry. Drilling is most frequently employed among machining processes for composite materials due to the need for structural integration. In this paper, some aspects of both experimental observation and machinability are presented for thermoset-based and thermoplastic-based composites with high and low fiber loading. The experimental observation discusses chip characteristics and specific cutting energy to reveal the mechanism of material removal. These materials fracture due to the brittle reinforcement, hence the sensitivity of defects in bulk volume is demonstrated. The level of fiber loading and the deformation behavior of matrix polymer determine the extent of plasticity in chip formation and the chip length. The discussions of machinability include drilling force, surface roughness and edge integrity affected by cutting conditions (feed rate and cutting speed), drill geometry and lay-up system. An optimal domain of cutting parameters is suggested for secured machinability.