Effect of cutting tool lead angle on machining forces and surface finish of CFRP laminates

Abstract

Machining is one of the most practical processes for finishing operations of composite components, allowing high-quality surface and controlled tolerances. The high-precision surface milling of carbon fiber-reinforced plastics (CFRP) is particularly applicable in the assembly of complex components requiring accurate mating surfaces as well as for surface repair or mold finishing. CFRP surface milling is a challenging operation because of the heterogeneity and anisotropy of these materials, which are the source of several types of damage, such as delamination, fiber pullout, and fiber fragmentation. To minimize the machining problems of CFRP milling and improve the surface quality, this research focuses on the effect of multiaxis machining parameters, such as the feed rate, cutting speed, and lead angle, on cutting forces and surface roughness. The results show that the surface roughness and cutting forces increase with the feed rate, whereas their variations are not uniform when changing the cutting speed. Generally, a lower surface roughness was achieved by using a lower cutting feed rate (0.063 mm/rev) and higher cutting speeds (250-500 m/min). It was also found that the cutting forces and surface roughness vary significantly and nonlinearly with the lead angle of the cutting tool with respect to the surface.