Temperature estimation in drilling processes by using an observer

Cutting temperatures have strongly influenced both the tool life and the metallurgical state of machined surfaces. Temperatures in drilling processes are particularly important, because chips remain in contact with the tool for a relatively long time in a hole. Tool temperatures tend to be higher in drilling processes than in other machining processes. This paper describes modeling of thermal behavior in drilling processes as well as estimation of the cutting temperature distribution based on remote temperature measurement. One- and two-dimensional estimation problems are proposed to analyze drilling temperatures. Observer algorithms are developed to solve inverse heat problems. Finite element methods are used to verify the estimated drilling temperatures. In the two-dimensional case, a moving heat source according to the feedrate is substituted into a fixed heat source with respect to the drilling location. Simulation results confirm the application of the proposed methods.