On-line estimation of the tool-chip interface temperature field during turning using a sequential inverse method

It is well known that the direct measurement of temperature distribution at the tool-chip interface in a machining process is difficult to accomplish. Thus, this paper provides an on-line inverse technique to estimate the temperature field at the tool-chip interface of a turning tool, using temperatures measured at some sensor-accessible locations. A sequential Tikhonov regularization method (STRM) is proposed to determine the transient heat flux imposed at the tool-chip interface, by solving an inverse heat conduction problem (IHCP). Then, the temperature field at the tool-chip interface is computed by solving the three-dimensional non-linear thermal model, with a method combining Duhamel’s superposition theorem with the finite element method. The procedure proposed shows a superiority in on-line applications due to its high computational efficiency and independence of future measurements. A comparison of the STRM with several other inverse methods in the literature was made through numerical tests. Experimental cutting tests on Ti-6Al-4V titanium alloy were done to validate the thermal model and method. Both numerical and experimental tests show that the proposed method can provide an efficient and easy-to-implement strategy for on-line temperature field monitoring of machine tools.