Evaluation of chip formation process in the grinding of GFRP and CFRP

Today, polyether ether ketone composites are widely used in the medical and aerospace industries due to their high strength-to-weight ratio, anti-allergic properties, high buckling resistance and fatigue. Grinding has a high specific energy among traditional cutting processes. Usually a high portion of energy will converts to heat. Because heat has an important role in polymer grinding, the heat modeling of it is necessary. In addition to the energy of chip formation during material removal, there are other energies such as plowing and friction energy. The contribution of each of these energies affects the efficiency of the process. By theoretical calculating of the cutting energy and comparing it with the experimental specific grinding energy, the portion of chip formation energy versus friction and plowing energy can be calculated. By performing differential scanning calorimetry test and theoretical calculations, the amount of chip formation energy was 0.089 and 0.119 J/mm^3 for GFRP and CFRP, respectively. While the experimental results of grinding showed a minimum specific energy of 2.2 J/mm^3 and 2.4 J/mm^3 for GFRP and CFRP, respectively. This difference indicates the very high portion of plowing energy in the grinding of this material and especially polymeric materials. The percentage of the chip-forming energy that enters the workpiece as heat was calculated to be 27%. Therefore, it can be stated that all energy except 73% of the chip formation energy enters the workpiece.