When optimizing the milling effect, the insert of the milling cutter is another important factor. In any milling, it is an advantage if the number of inserts participating in cutting is more than one at the same time, but too many inserts participating in cutting at the same time is a disadvantage. It is impossible for one cutting edge to cut at the same time. The required power is related to the number of cutting edges participating in the cutting. The position of the milling cutter relative to the workpiece plays an important role in the chip formation process, the cutting edge load and the machining results. In face milling, with a cutter approximately 30% larger than the cutting width and positioned close to the center of the workpiece, the chip thickness does not change much. The chip thickness in the plunge and exit is slightly thinner than that in the center cut.
To ensure that a sufficiently high average chip thickness/feed per tooth is used, it is necessary to correctly determine the number of teeth of the milling cutter suitable for the operation. The pitch of a milling cutter is the distance between the effective cutting edges. According to this value, milling cutters can be divided into 3 types - dense tooth milling cutter, sparse tooth milling cutter, and extra dense tooth milling cutter.
Related to the chip thickness of milling is the main declination angle of the face milling cutter. The main declination angle is the angle between the main cutting edge of the insert and the surface of the workpiece. There are mainly 45 degrees, 90 degrees and round inserts. The direction change will vary greatly with the different entering angle: a milling cutter with a entering angle of 90 degrees mainly generates radial force, which acts in the feed direction, which means that the machined surface will not be subjected to excessive pressure , It is more reliable for milling workpieces with weak structure.
The radial cutting force and the axial direction of the milling cutter with a leading angle of 45 degrees are roughly equal, so the pressure generated is relatively balanced, and the requirements for the power of the machine tool are relatively low, especially suitable for milling short-chip materials that produce chipping chips artifact.
A milling cutter with round inserts means that the entering angle varies continuously from 0 to 90 degrees, depending on the depth of cut. The strength of the cutting edge of this kind of insert is very high. Since the chips generated along the long cutting edge are relatively thin, it is suitable for large feeds. The direction of the cutting force along the radial direction of the insert is constantly changing, and the pressure generated during the machining process. Will depend on the depth of cut. The development of modern insert geometry makes the circular insert have the advantages of smooth cutting effect, low power requirement of the machine tool, and good stability. It is no longer an effective roughing cutter and has a wide range of applications in both face and end milling.
