Determination of the maximum temperature and temperature distribution along the rake face of the cutting tool is of particular importance because of its controlling influence on tool life, as well as, the quality of the machined part. Numerous attempts have been made to approach the problem with different methods including experimental, analytical and numerical analysis. Although considerable research effort has been made on the thermal problem in metal cutting, there is hardly a consensus on the basics principles. The unique tribological contact phenomenon, which occur in metal cutting is highly localized and non-linear, and occurs at high temperatures, high pressures and high strains. This has made it extremely difficult to predict in a precise manner or even assess the performance of various models developed for modelling the machining process. Accurate and repeatable heat and temperature prediction remains challenging due to the complexity of the contact phenomena in the cutting process. In this paper, previous research on heat generation and heat dissipation in the orthogonal machining process is critically reviewed. In addition, temperature measurement techniques applied in metal cutting are briefly reviewed. The emphasis is on the comparability of test results, as well as, the relevance of temperature measurement method to high speed cutting. New temperature measurement results obtained by a thermal imaging camera in high speed cutting of high strength alloys are also presented. Finally, the latest work on estimation of heat generation, heat partition and temperature distribution in metal machining is reviewed. This includes an exploration of the different simplifying assumptions related to the geometry of the process components, material properties, boundary conditions and heat partition. The paper then proposes some modelling requirements for computer simulation of high speed machining processes.

Heat generation and temperature prediction in metal cutting: A review and implications for high speed machining

Thermal modeling of the metal cutting process: Part I — Temperature rise distribution due to shear plane heat source

The results of a photographic technique for the determination of the complete temperature distribution in the orthogonal metal cutting process are presented; they are found to disagree with previous theoretical predictions. The temperatures along the tool rake face are of particular interest because they are thought to affect the wear of the cutting tool and friction between the chip and tool; it is found that these temperatures have been considerably over-estimated by previous work. By introducing the width of the secondary deformation zone, i.e. the extent of sub-surface deformation due to friction at the tool-chip interface, as a new variable, it is found that more consistent predictions of rake face temperatures can be made. From this work information has been obtained on the shape of the zones of plastic deformation in metal cutting and on the distribution of heat generation within these zones.

Temperatures in Orthogonal Metal Cutting

In this paper the process of orthogonal cutting is studied by analytical means. A thermomechanical model of the primary shear zone is combined with a modelling of the contact problem at the tool-chip interface. A friction law is introduced that accounts for temperature effects. The effects of cutting conditions and material behaviour on the temperature distribution along the contact zone, on the mean friction and on the global cutting forces are evaluated. The experimental trends are shown to be well described by the proposed model. © 1998 Elsevier Science Ltd. All rights reserved.Keywords : A. cutting and forming, thermomechanical processes, B. viscoplastic material, friction.

Modelling of orthogonal cutting with a temperature dependent friction law

Temperature distributions for typical cases of orthogonal machining with a continuous chip were obtained numerically by solving the steady two-dimensional energy equation using the finite element method. The distribution of heat sources in both the primary and secondary zones was calculated from the strain-rate and flow stress distributions. Strain, strain-rate and velocity distributions were calculated from deformed grid patterns obtained from quick-stop experiments. Flow stress was considered as a function of strain, strain-rate and temperature. The chip, workpiece and tool (actual shape and size) were treated as one system and material properties such as density, specific heat and thermal conductivity were considered as functions of temperature.

Using the Finite Element Method to Determine Temperature Distributions in Orthogonal Machining

The problem investigated involves consideration of the temperature distribution in a body moving relative to sources of heat. Relaxation and analytical methods of solution have been developed and applied to the work material, the chip and the tool considered as three separate problems. The results obtained have been compared with other analytical solutions and with indirect experimental evidence of the temperatures attained. The application of the methods has been restricted to the simplest ideal model of the cutting process. The methods may be modified to incorporate the effect of temperature on the thermal properties, yield stress, etc., of the work material and are capable of a wider application to analogous heat flow problems.

http://iopscience.iop.org/article/10.1088/0508-3443/5/11/306/pdf

A C Rapier

Papers

A theoretical investigation of the temperature distribution in the metal cutting process