Heat partition in edge trimming of fiber reinforced polymer composites

Thermal loading of fiber reinforced composites during traditional machining is inevitable. This is due to the fact that most of the mechanical energy utilized in material removal is converted into heat, which is subsequently dissipated into the workpiece and the cutter, and is carried away by the chips. Heat conduction into the workpiece during machining might cause thermal damage due to matrix softening and decomposition if the generated temperatures exceeded the glass transition temperature of the epoxy resin. In this work, the amount of heat flux applied to the machined edge and the temperature distribution in multidirectional CFRP and GFRP composite laminates was determined using an iterative inverse heat conduction method. The transient heat conduction problems in the laminate and cutter were simulated independently using the finite element method and the amount of heat flux applied to each was determined. It was also found that the heat flux conducted to the workpiece represented only a small fraction of the total heat and is more influenced by the feed speed than the spindle speed. The temperature of the machined surface was estimated and correlations with the resulting machined surface texture were made.