Machinability analysis of carbon fibre-reinforced plastics using compression tools

The widely spread use of polymer composites and their difficult machining behaviour have directly led to the appearance of tools with unique geometry, specialised for carbon fibre-reinforced plastics (CFRP). These so called compression tools are crafted in a way to reduce delamination, which is a common machining caused material defect. The present study focuses on the effect of technological factors on various optimization parameters in cases compression tools were used. Cutting width and feed rate have been chosen as factors. The factor levels have been determined beforehand, using central composite inscribed (CCI) design. The machining experiments were carried out on a Kondia B640 milling machine centre. A KISTLER 9257BA load cell was used for the measurement of the cutting force, likewise a Mahr Federal Pocket Surf IV instrument for surface roughness. Collected data were processed using analysis of variance (ANOVA) and response surface methodology (RSM) via Minitab 17. As a result of this research the change of tool-geometry and process parameters of CFRP machining were determined, induced by technological parameters, on two various compression tools. It was found that the feed rate has the most significant effect on the cutting force and surface roughness, followed by the cutting width.