Similarity and difference in machining at mixed scales using nanostructured coated tools milling hypoeutectoid carbon steel

Abstract

There are similarities and differences when machining at the microscale and macroscale. One difference is the lack of significant heat generated at the microscale, which means that thermal barrier coatings are largely redundant. However, the mechanisms of wear are similar and different depending on machining parameters. In this study, it is discovered that nanostructured coatings play different roles at mixed scales, which are experimentally determined by measuring tool wear, chemical diffusion, temperature, and forces. The main findings show that macroscale wear is thermal in nature and that microscale wear is primarily tribological. The principal conclusions focus on redesigning microtools and nanostructured coatings to eliminate wear, developing standards that describe the action of microtools, and understanding how to calculate the minimum chip thickness that guarantees the formation of chips rather than burrs.