The end mill. Structural features and function

The end milling cutter is a metal-cutting tool widely used in machine building, intended for processing various planes, ledges, grooves and shaped surfaces of complex geometry. The main feature of this tool is the possibility of simultaneous processing of two perpendicular planes, due to the presence of teeth on both the cylindrical and the end surface of the mill.

In its essence, the end milling cutter is a multi-blade metal-cutting tool of cylindrical shape, where each tooth is an independent cutter. Due to its design and high machine speeds, a high degree of purity is achieved by the surface being milled. When the tool rotates, its teeth (incisors) alternately come into contact with the material.

The end milling cutter, when performing the metal cutting operation, is perpendicular to the workpiece plane of the workpiece. At the same time, the main cutting load is taken by the cutting side edges located on the outer cylindrical surface, which contributes to their rapid wear. Of course, the end mills can be re-sharpened, but after such an operation their dimensions will invariably differ from the nominal ones.

In connection with this, special use is made of cutters of a prefabricated structure with interchangeable cutters made of different grades of high-speed steels and equipped with tungsten carbide inserts or cutting elements made of cermet. Such cutters and plates are fixed directly to the tool body. A distinctive feature of this type of milling cutter is the fixed installation of the cutting element relative to the tool body. End mills of this design have a constant geometry, determined by the accuracy of execution of the corresponding base surfaces of the tool body and the configuration of removable, non-re-threadable plates.

The main advantages of such a design solution include increased strength, due to the lack of internal stress of the metal, usually caused by the overflow. This increases the durability and longevity of the incisors by about thirty percent. In addition, such mills equipped with detachable plates, can significantly save carbide material, as waste tools can be sent to the melting, where they are extracted from tungsten and other expensive elements.

Characterized by face milling is higher productivity than for cylindrical milling. In our time, most of these operations are carried out with end mills. Special attention should also be paid to the geometry of the teeth. The cutting surface of each of them has sharpened working edges at a certain angle, which pass through the top of the tooth. Distinguish between the main and auxiliary cutting surfaces. The tip of the teeth of the end mill may have either a rectilinear shape or rounded contours. The latter variant demonstrates increased wear resistance and less dependence on the degree of beating of the cutting edge. Such cutters are mainly used for roughing and semi-finishing.

For milling operations on the processing of small ledges and flat open planes, a face milling cutter is usually used, equipped with insert knives, which are made of different grades of high-speed steels. Such a model, fixed on the mandrel or the landing end of the machine spindle, usually has a diameter of 40 or more millimeters, which makes it sufficiently rigid and massive tool.