Study of the stress-strain and temperature fields in cutting tools using laser interferometry

Introduction. The efficiency of the metalworking processes highly depends on the performance of the implemented cutting tools that can be increased by studying its stress-strain state and temperature fields. Existing stress analysis methods either have a low accuracy or are inapplicable for research during the operation of the tools made of materials with high mechanical properties. In addition, the study of temperature fields using known methods is difficult due to the small size of the cutting zone, high temperatures, and a heavy temperature gradient appearing during metal cutting. The purpose of this study is to develop new experimental methods for measuring the stress-strain and temperature fields in the cutting tool during its operation using laser interferometry. The methods include: obtaining interference fringe patterns using an interferometer with the original design, obtaining the tool deformation field during the cutting process by recording the changes in interference fringe patterns using a high-speed camera, processing fringe patterns with the separation of deformations caused by heating and cutting forces, and calculating temperature fields and stress distributions using mechanical properties and the coefficient of thermal expansion of the tool material. The advantages of the developed methods include: applicability under real operating conditions of the cutting tool, ability to study the non-stationary stress-strain state and temperatures during an operation, and achievement of a high spatial resolution and a small field of view for the investigated surface. Results and Discussion. The experimental study confirmed the efficiency of the methods. The results of the study included the fields of stresses and temperatures obtained during the orthogonal cutting of heat-resistant steel with a tool made of cemented tungsten carbide WC-8Co. The developed methods can be used to study the cutting tool efficiency at close to real conditions and in obtaining boundary conditions for the study stress-strain state of a workpiece material near the cutting zone.