Investigation of producing and turning of GFRP composites having different dimensions and rate

Glass fiber reinforced plastic (GFRP) composites have taken place in engineering materials because of low weight and high mechanical properties. They need to be shaped as machining in order to use them in the industrial applications. However, when these composites are machined, a number of problems are encountered. For eliminate or minimize these problems, optimization of cutting parameters are important. In this study, GFRP composites were produced by combining polyester matrix material with glass fibers (GF) having 6 mm, 6-12 mm, 12 mm fiber length, and weight 20%, 25%, 30% fiber content. The tensile strength of the produced composites was investigated. In addition, turning tests were made in cutting speeds of 40, 80 and 120 m/min, feed rate of 0.1, 0.2 and 0.3 mm/rev, and depth of cut parameters of 1, 2 and 3 mm. Turning tests were carried out according to the Taguchi L27 experiment design method. The effect of fiber ratio, fiber length and cutting parameters on cutting forces and surface roughness were analyzed. As a result of the experiments, it was observed that the GF reinforcement to polymer matrix material increased the tensile strength. For all fiber lengths, the highest tensile strength was obtained from the reinforcement rate of 25%. In point of fiber length, tensile strength was obtained as maximum in GFRP composites having 12 mm fiber length, as minimum in GFRP composites having 6-12 mm fiber length. In addition, in the turning of these composites, cutting parameters were found to be highly effective on the surface roughness and cutting forces. It was observed that cutting forces increased as the fiber ratio, fiber length, feed rate and depth of cut increased, however, as the cutting speed increased, the cutting forces initially increased and then decreased. It was seen that the most effective parameter on cutting force was feed rate followed by fiber ratio. On the other hand; the surface roughness value increased when fiber ratio, feed rate, cutting speed and depth of cut increased, and for 6, 6-12 and 12 mm fiber lengths, surface roughness initially increased and then decreased. The most effective parameter on surface roughness was feed rate followed by cutting speed. Feed rate was determined as the most effective parameter on both cutting force and surface roughness.