Material removal characteristics of metal-polymer composites in the cutting process

Metal-polymer composites are constantly developed and applied for numerous purposes due to some irreplaceable and adjustable properties like thermophysical, tribological or mechanical. The differences of mechanical and thermal conductivity between metal and polymer materials lead to different removal behaviors from traditional homogeneous materials. The improvement of machining surface quality becomes an urgent problem to be solved in expanding its application. In this work, material removal characteristics of copper particle-filled PTFE composites (Cu/PTFE) material in cutting process were investigated. Dynamic mechanical analysis (DMA) experiments were applied to investigate how the temperature affected the mechanical characteristics of the Cu/PTFE materials. Then the material removal mechanism was studied by simulation and experiment. The results revealed that there are three simultaneously exist removal modes of the Cu/PTFE material, depending on the position of the particles relative to the cutting edge and the cutting temperature. An important finding is that the difference between the actual roughness and the theoretical roughness based on the tool envelope model is linearly related to the cutting temperature. This is mainly due to the approximately linear decrease of the storage modulus with temperature. With rising temperature, the material's storage modulus exhibited a tendency to decrease and a poorer mechanical loss at glass transition temperature was also certificated. The material removal characteristics of the cutting Cu/PTFE surface and its underlying mechanism revealed in this paper are instructive for determining the machining parameters to improve the surface quality.