Effect of tool geometry and flank wear on drill temperature during CFRP machining

Carbon Fibre-Reinforced Polymers (CFRP) are a fast growing market of high performance materials and components. Thermally induced damage during machining processes such as drilling or routing are among the limiting factors for product quality, yet accurate temperature measurement remains challenging. This study develops a methodology which combines machinable thermocouples and IR thermometry techniques to measure the temperature of the drill. Proposed combination, further enhanced by careful synchronization, timestamping and postprocessing, allows fine resolution analysis of local temperature along the cutting edges. The study compares three different designs of drills and the impact of their geometry and wear on generated temperature. The results indicate that positive rake angle is a favourable geometric feature which allows to maintain lower local temperature of 129-142 °C in unworn state.