Thermal modelling of cutting tool temperatures and heat partition in orthogonal machining of high-strength alloy steel

Abstract

Cutting temperatures and heat partition into the cutting tool are critical factors that significantly affect tool life and part accuracy during metal removal operations, especially in dry machining. Among many thermal modelling studies, uniform heat partition ratio, and/or uniform heat intensity along the tool-chip interface are frequently assumed. This assumption is not valid in actual machining and can lead to erroneous estimated results in the presence of sticking and sliding friction zones. Therefore, it is necessary to accurately predict the cutting tool temperature and heat partition during machining. This paper presents an analytical thermal modelling approach which considers the combined effect of the primary and the secondary heat sources and determines the temperature rise and non-uniform heat partition ratio along the tool-chip interface. Cutting tests were conducted on AISI/SAE 4140 high-strength alloy steel using carbide cutting tools over a wide range of cutting speeds. Cutting temperatures were measured experimentally using an infrared thermal imaging camera. Experimentally established sticking and sliding friction regions were used to evaluate non-uniform frictional heat intensity along the tool-chip interface. The temperature matching condition along the tool-chip interface leads to the solution of distributed non-uniform heat partition ratio by solving a set of linear equations through programming in MATLAB®. Experimental results show to be consistent well with those obtained from the thermal model, yielding a relative difference of predicted average tool-chip interface temperature from −0.8% to 6.3%. It is found that average heat partition into the cutting tool ( RT) varies from 35% down to 15% for the entire range of cutting speeds. These results suggest that, to address the thermal problem in metal cutting, the research and development of tooling should also focus on reducing friction on the tool rake face in addition to the contribution of the combined effect of primary and secondary heat sources on temperature rise at the tool-chip interface.

On the correlation between processing parameters, plastic deformation, and mechanical property in hard machining of H13 steel

“…It is confirmed that the higher cutting speed leads to an elevated cutting temperature. 48 Under this circumstance, tensile residual stress is more intended to generate within the machined surface layer due to thermal expansion. After all, fatigue crack is more prone to initiate from the machined surface, 49 especially if the generated residual stress is in a tensile state, which thus causes a significantly decreasing fracture toughness.…”

Application of Adaptive Materials and Coatings to Increase Cutting Tool Performance: Efficiency in the Case of Composite Powder High Speed Steel

“…The contact areas of the rubbing surfaces of the tool, chips, and workpiece being processed are small, and the pressure and friction rate exerted on them are extremely high. The high temperature in the cutting zone is the cause of structural changes in the material of the cutting tool and the reason for the rapid loss of its performance [88][89][90]. Therefore, to explain the physical nature of the increase in the tool material durability, it is crucial to study the changes in temperature fields in the cutting wedge of the tool during operation.…”

A Comparative Review of Thermocouple and Infrared Radiation Temperature Measurement Methods during the Machining of Metals

“…Metal machining creates substantial thermal and mechanical loads that can impact the mechanical behaviours of both tools and workpieces [1][2][3][4][5][6][7]. However, the machining industry focuses more on the mechanical loads of the operations.…”