The mathematical modelling of the impact of electric (Seebeck) effects on end-milling

Abstract

It is a well-known fact that thermoelectric currents, reaching even the scale of ampere, develop during chip formation in the machine-workpiece-tool-chip. The impact of these currents on tool wear in end-milling was examined with a qualitative thermoelectric model, in which wear is described by an autonomous non-linear differential equation. Cutting temperature was measured by a so-called natural thermoelement with C60 and P35 carbide pair, which were submerged into heated Sn bath at validation. The mathematical model can be solved by a numerical method, where the inverse of the differential equation of wear was used. The wear curves determined by calculation fitted well with the measurement results. The results were achieved by cutting experiments using P35 carbide conducted on the C45 quality steel workpiece. It was found that the optimal solution with respect to the wear of the tool behaving as a natural thermal element might be achieved if the current is compensated by an external power source. Based on the model, anomalies might occur in some cases in the thermoelectric system. Further research is necessary to decide if this is only a special characteristic of the model or the model is interpreting really the actual processes.