Studying the effects of coatings on the thermal protection of cutting tools during turning via a nonlinear inverse heat conduction problem

• Published in: International journal of advanced manufacturing technology 2023-12, Vol.129 (7-8), p.3009-3026
• Main Authors: Corrêa Ferreira, Diego, Viana Avelar Dutra, Fernando, Gustavo Dourado da Silva, Rodrigo, Metrevelle Marcondes de Lima e Silva, Sandro, Roberto Ferreira, João
• Format: Article
• Language: English
• Subjects: Aluminum oxide; CAE) and Design; Cast iron; Coatings; Computer-Aided Engineering (CAD; Conduction heating; Conductive heat transfer; Cutting force; Cutting parameters; Cutting speed; Cutting tools; Engineering; Function specification method; Heat; Heat flux; Industrial and Production Engineering; Inserts; Mathematical analysis; Mechanical Engineering; Media Management; Nodular cast iron; Nodular iron; Nonlinearity; Original Article; Substrates; Temperature; Temperature gradients; Temperature sensors; Thermal protection; Titanium carbonitride; Turning (machining)
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-023-12473-z

Inserts are significantly affected by heat and mechanical stress in turning processes. Over time, improvements have been made to these inserts to attenuate these impacts. One such enhancement involves applying coatings. While cutting temperatures have been widely studied, there is a lack of information on quantifying the thermal protection offered by coatings on insert substrates and the relationship to tool-chip contacts. This study examines these characteristics, considering factors like the tool-chip contact area, cutting forces, cutting speed, and the presence of coatings. We considered two cutting tools, one uncoated and the other coated with TiCN, Al 2 O 3 , and TiN. Regarding the methodology, we measured temperature fluctuations at accessible points on the insert during turning of a nodular cast iron GGG40. These temperature readings were then used to estimate the heat flux at the tool-chip contact area. We employed the adaptive sequential function specification method (ASFSM) for this purpose. Noteworthy aspects of this technique include its ability to handle nonlinearity, and it makes use of multiple temperature sensors to estimate heat flux. Upon comparing the confidence intervals, we observed that the method employed in this study yielded a temperature difference between the numerical and experimental results that was 35% smaller than the maximum variation observed in experimental replicates. This confirms the effectiveness of the method and validates the analyses conducted. Upon evaluating the insert, we observed that the presence of coating reduced the tool-chip contact area. Furthermore, at increased cutting speeds, the coating enhanced the thermal protection of the substrate.