Temperature variation depending on cutting conditions and its effects on thrust force in micro-drilling of CFRP laminates

Heat generation is unavoidable in machining processes and detrimental in many aspects. Elevation of cutting temperature may cause the matrix burning and rapid tool wear and also influences the thrust force, which is related to the delamination damage. In this work, micro-drilling induced temperature in the CFRP laminates has been investigated experimentally by taking into account the effects of cutting speed and feed. Thermocouple and infrared thermography methods have been used to measure the generated temperature during the process. Variation of thrust force was introduced as the micro-drill penetrates the CFRP laminate. The thrust force was also divided into its components, and the contribution of each component to the thrust force was explained. The effects of generated temperature on the thrust force were evaluated. It was derived from the temperature measurements that generated temperature is sensitive to both feed and spindle speed variations, but the feed is more effective on the generated temperature than the spindle speed in the selected range. It was observed that the thrust force changes significantly as the micro-drill cuts the carbon fibre intensive and epoxy intensive layers, and cutting temperature affects the highest thrust force significantly.