Investigation of micromilled tool steel H13 using tungsten carbide micro-end mills

Micromilling allows for the high precision machining of different types of materials and thus promotes the manufacturing of micro-components for various technological applications. Evaluating tool wear in micromilling poses challenges not yet fully researched, more specifically the widely known size effect of micromilling processes contributes to an intricate cause-and-effect mechanism, and its research requires an understanding of the relationship of machining parameters in order to improve the process control. Thus, this paper researches the relationship between flank wear, feed, and specific cutting forces and roughness for the tool steel H13. Experiments with different levels of feed per tooth and spindle speed were carried out to measure and analyze tool flank wear, cutting forces, and the roughness of the workpiece. The lowest roughness value (Rz < 200 nm) was obtained for the feed per tooth of 2 mu m at the beginning of the cut. However, this parameter also presented the highest flank wear, which led to the highest roughness value (Rz = 423 nm) at the final cutting length. Moreover, the interaction between the parameters feed per tooth and spindle speed occurs only at the maximum feed per tooth level. Increasing the feed per tooth to 5 mu m and the spindle speed to 46,000 rpm significantly reduces flank wear. This behavior shows that not only increased feed rate but also increased spindle speed provided a combined reduction in plowing and improved shear mechanism.