Multi-sensor monitoring of drilling in advanced fiber reinforced composites

This paper investigates the main effects of drilling parameters (cutting speed, feed rate, tool geometry, and tool material) on cutting force and hole quality during drilling of magnamite graphite fiber reinforced polyether ether ketone (AS4/PEEK) composites. The AS4/PEEK is a one hundred and ninety nine-ply [0°/45°/90°/-45°]_s laminate composite. Taguchi orthogonal array L₉ technique is used to plan a 3⁴ robust experiment. The workpiece is supported on a fixture and mounted on a 3-component piezoelectric transducer Kistler type 9257A model. The response signals (cutting force and acoustic emission) are acquired simultaneously during the drilling experiments. The signals are instantaneously sampled and stored in a pentium computer for later processing. The digitized signals are processed in time domain. Surface profilometer is used to measure the surface roughness of the drilled holes. The optimum drilling condition is determined by meticulous examination of the drilling parameter' s main effects . The responses are analyzed based on Taguchi' s signal-tonoise ratio (SIN) as opposed to the measurement data and analysis of variance (ANOVA). The results show that sensor signals, delamination and surface roughness measurements are well correlated with the drilling parameters. Optimum drill tool materials, drill point angle and cutting conditions have been determined.