What are the three wear states of end milling cutter for turning milling
In turning milling compound machining, the wear of the rear face of the end mill mainly includes the wear of the main rear face and the wear of the auxiliary rear face. The wear of the rear tool surface is caused by the strong friction in the tool workpiece contact area, and there are obvious signs of mechanical friction in the wear area.
1. Uniform wear of main and rear cutter faces
During turning and milling, the wear of the main and rear tool surfaces is an equal width wear band at the initial stage of wear, and extends on the rear tool surface adjacent to the entire cutting edge. Figure (a) is the schematic diagram of uniform rear tool surface wear. The width of this wear band is called VB, which is a commonly used wear evaluation index. The wear of the rear face will intensify the cutting friction in turning and milling, increase the cutting force, increase the cutting temperature and reduce the processing quality. Figure (b) shows the actual wear effect of the main and rear face of the end mill at the initial wear stage.
2. Local wear of main and rear cutter faces
Among the end milling cutters tested, a part of the cutters have serious wear in the local range of the main and rear cutter surfaces, and develop in this specific part. Figure (c) shows the local wear of the main and rear cutter surfaces of the neutral milling cutter for turning and milling. This wear pattern is caused by the friction between the peripheral edge and the surface to be machined of the workpiece in the turning milling composite processing, and the deep grooves are grinded. The local wear of the rear tool surface generally occurs in the middle and later stages of turning milling processing.
3. Wear of auxiliary rear cutter face
In turn milling process, the auxiliary cutting edge is the end face edge of the end mill. Because the workpiece is also rotating during the machining process, the contact frequency between the flank and the machined surface becomes faster, so the flank wear in turning milling process is much more serious than that in ordinary milling. Figure (d) shows the wear of the rear tool face of the pair in turning milling composite processing.