Advanced approach of forming cutting edge radii on cemented carbide cutting tools using plasma discharges in electrolyte

The paper deals with the task of preparing cutting edge microgeometry. Unconventional methods for edge preparation are presented, and an overview of articles, patents, and reports that deal with modern and advanced approaches are stated. Moreover, an innovative cutting edge preparation method using plasma discharges in an electrolyte was examined. The main aim was to determine the effect of the process parameters, namely electrolyte concentration, the temperature of the electrolyte, the voltage between electrodes and the operating time, on the shape and size of the cutting edge rounding as well as surface roughness and topography. The tested type of cutting tool was cutting insert. The cutting inserts were made of cemented carbide (WC + Co). It was examined that cutting edge radius sizes were strongly affected by the process parameter of plasma discharges in electrolyte as well as the shape of rounding. However, specific types of defects can occur on the cutting edge after edge preparation using plasma discharges in electrolyte. These defects can be avoided by correctly setting the process parameters. From the results of the experimental research, it was confirmed that cutting edges can be rounded without defects in the entire range of electrolyte concentration, but the setting of voltage and temperature of the electrolyte must be simultaneously considered. Furthermore, decreasing the electrolyte concentration, the temperature of the electrolyte and the voltage between electrodes resulted in a larger cutting edge radius. Cutting edge preparation using plasma discharges in electrolyte takes only a few seconds, depending on the cutting edge radius sizes. Cutting edge radii with a value of 20 μm were manufactured in 30 s. This innovative advanced edge preparation method is one of the most productive edge preparation methods. An even more important aspect is not to burden the environment with hazardous waste such as acids because this electrolyte solution can be prepared by dissolving a small amount of salt in tap water. The issue of the topography of the surface of cemented carbides after PDE treatment should be expecially heeded.