Temperature measurement of cutting tool and machined surface layer in milling of CFRP

• Cutting temperature of CFRP was measured by the tool-workpiece thermocouple method.
• The cutting point temperature exceeded the glass-transition temperature.
• Temperature of machined surface layer was measured with an embedded thermocouple.
• Temperature of machined surface layer decreases steeply as apart from the surface.
• SEM observation of machined surface revealed that the matrix resin was not damaged.

The measurement of cutting temperature is important when dealing with carbon fiber-reinforced plastics (CFRPs). Temperatures higher than the glass-transition temperature of the matrix resin are not favorable as they damage the CFRP. In this research, the cutting temperature in the endmill machining process was measured using three methods. The measured cutting point temperature exceeded the glass-transition temperature. However, the influence of temperature elevation at the cutting point could be reduced by taking a suitable distance from the machined surface depending on the cutting speed. In addition, observation of the machined surface with SEM revealed that the matrix resin at the machined surface was not damaged even if the cutting speed was over 300 m/min. This phenomenon depends on the low thermal conductivity of the CFRP. Therefore, high-speed cutting is applicable for the milling of CFRP.