Tool wear, surface roughness, electric current, and chip morphology in the turning of AISI 1045 steel with minimum quantity lubrication (MQL) technique

The cutting fluid application in turning process using the MQL technique is a viable option to optimize the process in terms of cutting tool performance and machined part characteristics; in addition, the MQL technique is environmentally friendly. In this work, the influence of cutting speed (v_c), feed rate (f), and lubrication-cooling condition (dry and MQL) in the turning of AISI 1045 steel was investigated. For this, the cutting tool wear, the surface roughness, the electrical current required by the machine tool, and the chip morphology were analyzed. The maximum flank wear values (VB_Bmax) showed that the MQL technique can reduce the wear of cutting tools. The values of the roughness parameter Ra indicated low influence of the application of the MQL technique on the surface finish. The greatest influence on this output variable was exerted by feed rate (f). The increase in cutting speed (v_c) and feed (f) values increased the measured electric current. The application of the MQL technique was able to reduce the electrical current values required by the machine tool, which are directly proportional to the cutting efforts. Analysis of chip morphology showed that for all cutting conditions adopted, segmented chips were formed. The analysis of the front and back surfaces presented results that corroborate the analyzes of wear, roughness, and electric current. Therefore, it was possible to infer that the application of the MQL technique can reduce friction, temperature, and cutting efforts, as well as being able to change the chip morphology.