Multi-material laser powder bed fusion of embedded thermocouples in WC-Co cutting tools

Abstract

During machining processes, due to deformation of the material and friction of the chip along the tool surface, a significant amount of heat is generated, particularly in the cutting zone, thus leading to a wear increase and consequent tool life reduction. Therefore, the ability to assess the cutting temperature in real time is extremely important to better understand heat generation, thus contributing to the development of more effective strategies for reducing machining costs and increasing tool life and productivity.This work proposes the fabrication of embedded additively manufactured K-type and N-type thermocouples in sintered WC-Co substrates by multi-material laser powder bed fusion for cutting temperature measurement in real time. Results showed that this approach is able to produce dense and continuous K-type and N-type embedded thermocouples with no evidence of severe defects, being found in the calibration tests a linear relationship with temperature, with a Seebeck coefficient at 20 °C of 40.8 μV/°C for K-type thermocouples and 16.5 μV/°C for N-type thermocouples. Turning tests revealed that the developed multi-material laser powder bed fusion approach is effective for manufacturing WC-Co cutting tools with 3D printed embedded thermocouples with the ability to measure precisely and accurately cutting temperature in real time during machining processes.