Estimation of heat flux and temperature field during drilling process using dynamic observers based on Green's function

This study presents an inverse technique to estimate temperature and heat flux at the tool–piece interface during drilling process. The technique used a method based on Green's function and dynamic observers. While most works found in literature focused the tool, in this study the work piece was modeled thermally. The thermal model was obtained by numerical solution of the transient three-dimensional heat diffusion equation considering the drill as a moving heat source. Two numerical simulations were performed in order to evaluate the thermal model, the inverse algorithm and to locate measurement regions with low sensitivity. Finite volumes method was used to solve the heat diffusion equation. Experimental tests were performed using cemented carbide tool to drill a micro-alloyed steel workpiece (HSLA steel- High-Strength Low-Alloy). The heat flux generated at the cutting interface during the drilling process was estimated using the developed inverse technique and only experimental data from the heating period was used. After heat flux estimation the temperature field was calculated. Comparisons between experimental and estimated data present a good accordance for the thermocouples not used in the heat flux estimation. ► Temperature and heat flux estimation during a drilling process is presented. ► The inverse technique uses a method based on Green's function and dynamic observers. ► A numerical solution of the transient 3D heat diffusion equation is used. ► Cemented carbide tool drilling a micro-alloyed steel workpiece were tested.