There are several main ways of tool cutting.

Use the rotary milling cutter as a tool to cut. Milling is generally carried out on a milling machine or boring machine, which is suitable for machining planes, grooves, various molding surfaces (such as spline shafts, gears and threads) and special-shaped molds. The characteristic of milling is that each cutter tooth of the milling cutter periodically participates in intermittent cutting; During the cutting process, the cutting thickness of each cutter tooth will change. Figure 1 Several common milling methods are several common milling methods.

The cutting speed v (m/min) is the peripheral speed of the milling cutter blade. There are three ways to express the milling feed: feed vf (mm/min) per minute, which means the displacement of the workpiece relative to the milling cutter per minute; The feed per revolution f (mm/rpm) indicates the relative displacement between the milling cutter and the workpiece per revolution; The feed per tooth af(mm/ tooth) indicates the workpiece processed by the milling cutter every turn. Milling depth ap (mm) is the contact length between the milling cutter and the workpiece measured parallel to the axis of the milling cutter. Milling arc depth ae (mm) is the depth of the contact arc between the milling cutter and the workpiece measured perpendicular to the axis of the milling cutter. The cutting speed of high-speed steel milling cutter for medium carbon steel is generally 20 ~ 30m/min；. It can reach 60 ~ 90m/min with cemented carbide milling cutter.

Milling is generally divided into two ways: peripheral milling and end milling. Zhou Xi

(Figure 2: Two methods of peripheral milling) It is milling with the cutter teeth on the circumference of the cutter body, and its peripheral edge plays a cutting role, and the axis of the milling cutter is parallel to the machining surface of the workpiece. End milling (the three end milling methods in Figure 3) is milling with the teeth on the end face of the tool body. The peripheral edge and the end face edge play a cutting role at the same time, and the axis of the milling cutter is perpendicular to the machined surface. Circumferential milling and some asymmetric end milling are divided into reverse milling and forward milling. Where the cutting direction of the blade is opposite to the feeding direction of the workpiece, it is called reverse milling; And the same direction is called downstream milling. In reverse milling, the cutting thickness of each tooth of the milling cutter increases gradually from zero, so when the cutter tooth starts to cut in, it will be squeezed and rubbed by the cutting surface, which will adversely affect the life of the milling cutter and the surface quality of the milled workpiece. The situation of forward milling is just the opposite, so forward milling can improve the life of milling cutter and milling surface quality, and reduce the power consumption of machine tools. However, the cutting impact of the milling cutter is great during forward milling. When there is a gap in the feed transmission mechanism of the machine tool or the cast-forged blank has hard skin, forward milling is not suitable to avoid vibration damage to the cutter.

Milling cutter is a kind of multi-tooth cutter. The total length of cutting edge involved in cutting is long, so it can use high cutting speed and has no idle stroke. So generally speaking, the productivity of milling is higher than that of single-edged tool cutting (such as planing and slotting), but the manufacturing and sharpening of milling cutter is more difficult.