Nowadays the usage of glass fibre-reinforced plastics (GFRP) is increasing. The cutting of these materials entails several problems, e.g. the strong abrasive wear effect of the glass fibres or delamination effects. In this paper, we examine the results of drilling experiments on a 10 mm thick GFRP which included 26 layers. The cutting parameters were changed over a wide range. During the experiments, we measured the average surface roughness parameter (Ra). After the tests, we examined the effect of the cutting parameters on the measured roughness values. We created two types of predictive model to estimate the roughness parameter and compared their applicability.
The use of fiber-reinforced plastics has increased significantly in the past decades. Consequently, the demand for finishing and machining of such materials has also escalated. During machining, the fiber-reinforced materials exhibit machining problems dissimilar to the problems of metals. These are fiber pull-out, fiber breakage in the cutting zone, matrix smearing and delamination. The purpose of this experiment is to investigate the characteristics of the resultant force (Fe) dur-ing the milling of carbon fiber reinforced plastic as a function of input machining parameters. For the force measurements, CFR with perpendicular (0°-90°) fiber orientation was machined. The experimental design involved the central composite design method. To analyze and evaluate the measurements, we applied the response surface methodology.
Super duplex stainless steels are used in increasingly more areas. The machinability of duplex stainless steels is generally poor. We performed dry turning tests on G X2CrNiMoCuN 26-6-3-3 casted superduplex steel, using two different PVD coated cutting inserts. One of them was coated with TiAlN and other with TiAlSiN. Strong burr and built-up edge formation were observed during our machining experiments; these damaged the edges of the tools. The shortened tests did not show significant difference betwen the effect of the coatings.