Effect of machining parameters on the mechanical properties of high dosage short –carbon- fiber reinforced composites

The machinability of polymer matrix composites with fibers strongly depends on the type of fiber and dosage in question, having a high influence on the selection of tools and cutting parameters. The cutting temperature depends of rotation and feed cutting tools and is significantly influencing on the quality of the machined surfaces and tool life. This paper presents the results of a current study concerning the effect of the rotation-cutting speed on the cutting temperature, roughness and tensile strength of short carbon fiber reinforced epoxy composites, potentially used in automotive and aeronautic industries. Composite plates were manufactured by compression molding, using short carbon fibers with length from 0.5 mm and 6 mm. The increasing of the rotation-cutting speed increases significantly the temperature generated in the tool and slightly increases surface roughness. Tensile strength and Young´s modulus are little sensitive to drilling speed. However, above 3000 rpm it was observed significant loss of stiffness, associated with the developed temperature in the machining process.