Cutting Forces and 3D Surface Analysis of CFRP Milling

Due to the wide application of Carbon Fiber Reinforced Polymer (CFRP) composites in various industries, more and more attention is paid to machining these materials. One of the most popular way of machining composites is the milling. Milling of composite materials (CM) is a difficult technology due to their anisotropic and heterogeneous structure and the fact that the reinforcing fibers have an intense abrasive effect on the tool edge during machining. The appropriate selection of technological cutting parameters as well as the type and geometry of the tool can significantly affect the value of cutting forces during milling and the quality of the surface after machining. The aim of the paper is to assess the influence of used tools (differing in the number of cutting edges) and various technological parameters of surface milling of CFRP composites on the cutting forces occurring during machining and on the surface quality after machining. Cutting forces were measured during the milling process on a special stand produced by Kistler and the roughness measurements and surface structure were analyzed using the Alicona InfiniteFocusG5 3D optical microscope. On the basis of performed research it was found that 14 edge tool gives lower values of Fx and Fy components of the cutting forces comparing to 2 edge tool, which is especially noticeable at higher cutting speed values vc=160 m/min, where the values of Fx and Fy components decreased by about 43% at fz=0.0030 mm/tooth. This tool gives also lower values of the Sa roughness parameter 1.65 µm.