Investigating the effect of fiber angle on the quality of the surface and delamination in the turning of epoxy composite reinforced with glass fiber

Composites containing glass fiber reinforcement are used in important industries such as aerospace, automotive, and petrochemical due to their low weight, high abrasion resistance, and excellent resistance to ultraviolet light. Achieving a part in the desired shape and with a suitable quality surface is the main challenge for researchers and machining specialists. Due to the heterogeneous and anisotropic structure of composite materials reinforced with glass fibers, the machining of these materials often leads to failures such as matrix cracking, fiber pull-out, delamination, etc. on the surface of the workpiece. The failure behaviors are not caused by the heterogeneous and anisotropic structure of the composite but rather by the machining methods and the interaction between them. One of the most influential factors on the surface quality of fiber-reinforced composite parts is fiber orientation, which is studied in this research. Examining the orientation of glass fibers in 3 directions of 0 (zero), 45, and 90 degrees on the structure of the final surface of the epoxy-fiber composite in this research showed that the roughness of the surface increases with the increase of the fiber angle from zero to 90 degrees. Also, the obtained results showed that the delamination of the workpiece surface in the direction of 45 degrees is greater than in the two directions of 90 and zero degrees.