Influence of cutting tool and conditions on machinability aspects of polyphthalamide (PPA) matrix composite materials with 30 % glass fiber reinforced

Abstract

Despite the importance of the polyphthalamide (PPA) composites in many industrial applications, especially for automotive industry, very little is known about the machinability of these composites. This paper presents the drilling characteristics of PPA matrix composite materials having glass fiber of 30 % reinforced by using HSS, TiN-coated HSS, and carbide drills. The influence of cutting parameters, for example cutting speed and feed rate, on the delamination factor and surface roughness of the composites has been examined during the drilling operations. Experimental results have demonstrated that as cutting speed increases, surface roughness decreases, and as feed rate increases, surface roughness increases as well. Higher cutting speeds and lower feed rates generate better surface quality. The drilling test results have demonstrated that the delamination factor increases through the increase of feed rate and decreases through the increase of cutting speed. It is obtained the best results of the delamination factor at higher cutting speeds and lower feed rates. The machined surface is examined by means of scanning electron microscopy (SEM). SEM images of the machined surfaces show the presence of cracks, fiber pullout, and shearing of fibers.