Model-based monitoring of temperatures and heat flows in the milling cutter

Abstract

The quantification of the heat flow distribution in the cutting zone is still an unsolved problem from an analytical as well as experimental perspective. Yet the heat flows into the tool and the time-variant temperature fields in the tool significantly influence the tool wear rate. This publication shows the results of a model extended measuring approach in order to monitor as well as investigate heat flows and their partitioning in the milling process under dry conditions. Therefore, the cutting power in the process was measured by means of a dynamometer as well as the temperature in the tool by an embedded thermocouple. The time response of the embedded thermocouple was accounted by an analytical time response function. By further data post processing of the temperature, the heat flow into the tool was inversely determined by comparison of the measured temperature trend at a distinct point with an analytically modeled, transient temperature as a solution of the heat conduction equations by a Green’s function. As input into the analytical model, an iteratively determined partition of the measured time-variant cutting power signal was used. The results showed a decreasing heat partition into the tool with rising cutting velocity. The introduced approach is a valuable tool not only to determine the heat partition in the milling process but also to understand and monitor the comprehensive thermo-mechanical conditions in the cutting zone. Understanding and monitoring thermo-mechanical conditions in the cutting process finally enable the exploitation of economic and ecologic process potentials.