ORIGINAL ARTICLE Influence of cutting tool and conditions on machinability aspects of polyphthalamide (PPA) matrix composite materials with 30 % glass fiber reinforced Ferit Ficici 1 & Zekeriya Ayparcasi 1 & Huseyin Unal 1 Received: 23 May 2016 /Accepted: 17 October 2016 # Springer-Verlag London 2016 Abstract Despite the importance of the polyphthalamide (PPA) composites in many industrial applications, especially for automotive industry, very little is known about the machin- ability 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 ex- amined during the drilling operations. Experimental results have demonstrated that as cutting speed increases, surface roughness decreases, and as feed rate increases, surface rough- ness 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 scan- ning electron microscopy (SEM). SEM images of the ma- chined surfaces show the presence of cracks, fiber pullout, and shearing of fibers. Keywords PPA matrix . Glass fiber . Drilling . Machinability . Surface roughness . Delamination factor 1 Introduction Machining of glass fiber-reinforced polymer (GFRP) compos- ite materials has always been difficult because of multitude of difficulties encountered suchlike fiber pulling out, fiber fuzzing, matrix burning, and fiber-matrix detachment, which result in subsurface damage, reduced strength, and short prod- uct service life. Drilling has a very important role in the cutting process because more than 40 % of material removal process- es are drilling. [1]. The improvement of the drilling process of fiber-reinforced polymers (FRPs) is important not only for decreasing the manufacturing costs but also for improving the part quality [2]. It should be kept away from the delamination phenome- non as its well-known negative effect on mechanical behavior [3]. Delamination is a major problem with respect to drilling fiber-reinforced composite materials and also reducing the structural integrity of the material. Moreover, it causes poor assembly tolerances, and it has the potential for long-term performance deterioration [4]. Delamination occurs both at the entrance and the exit planes of the hole [5]. Davim et al. [6] have examined the influence of cutting parameters and the matrix on the specific cutting force, delam- ination factor, and surface roughness. It has been determined that the feed rate is the most influencing parameter on delam- ination factor. Hocheng and Tsao [7], in their study on drilling of composite materials with various drill bits, have submitted a comprehensive analysis of delamination in use of various drill types, such as saw drill, candle stick drill, core drill, and step drill. In their analysis, the delamination is predicted and compared by twist drill. Many researchers have carried out studies on drilling of composite materials. Ogawa et al. [8] examined the relation between the cutting force and the surface roughness of a drilled hole. They have found that the major cutting edge of * Ferit Ficici fficici@sakarya.edu.tr 1 Faculty of Technology, Sakarya University, 54187 Sakarya, Turkey Int J Adv Manuf Technol DOI 10.1007/s00170-016-9626-9