Study on surface defects in five-axis ball-end milling of tool steel

The AISI P20 tool steel is widely used for manufacturing the plastic mold components, while surface defects problem often arises during ball-end milling process, which can deteriorate the fatigue life of the plastic molds. Therefore, it is vital to reveal the formation mechanism of the surface defects. First, a surface topology predictive model is conducted which is verified by experimental results; in addition, according to the simulation and experimental results, tool wear, surface topology, and surface profile are analyzed. Secondly, the origin of the surface defects is analyzed on the basis of the scanning electron microscope (SEM) images, and the relationship between the chip and surface defects is also discussed. Based on the investigation, the cutting friction and heating rather than the carbide particles are the main reason for surface defects in milling AISI P20 steel. This research is beneficial for the understanding of surface topology and surface defect formation mechanism. Meanwhile, the results could provide a technical base for selecting cutting parameters in five-axis ball-end milling of AISI P20 steel.