There are two kinds of spinning forming: ordinary spinning and powerful spinning. The spinning that does not change the thickness of the blank but only changes the shape of the blank is called ordinary spinning forming; The spinning that changes the thickness and shape of the blank is called strong spinning forming. The spinning force required by the powerful spinning forming is large, and the structure of the spinning machine is generally complex. The powerful spinning forming can be divided into forward spinning and reverse spinning according to the direction of the roller movement and the direction of the metal flow. The rotation wheel moves in the same direction as the metal flow, which is called positive rotation; On the contrary, it is called counter rotation. For the same material, the spinning force required for reverse spinning is large. The spinning method to be used shall be determined according to the shape and process requirements of the parts.

The type selection of spinning machine is determined by spinning process and various forming process conditions. Spinning machine is divided into two types: powerful spinning machine and ordinary spinning machine. The powerful spinning machine is divided into double spinning wheels and three spinning wheels. There are also spinning machines for spinning special parts, such as hot spinning machines, steel ball spinning machines, etc.

In mechanical products, how to save raw materials can improve product quality, reduce product weight can prolong service life, reduce product manufacturing cost and energy consumption can reduce processing hours has always been a concern. For example, "V" pulley (commonly known as "V" pulley) is one of the mechanical transmission parts with a wide range of applications. It is of great significance if it can be formed from steel plates. Compared with the traditional cast iron pulley, the sheet metal pulley can save more than 70% of raw materials. The spinning belt pulley formed by stretching and spinning of metal sheet metal is the latest and best belt pulley structure. This kind of pulley not only has the advantages described above, but also has no environmental pollution. It is especially widely used in automobiles, tractors, harvesters, air compressors and other mechanical products. The steel sheet blank is made of plastic deformation from point to line and from line to surface on the special belt pulley spinning machine tool.

Spinning pulley generally has three basic forms: folding pulley, split pulley and rolling multi V pulley (also called multi wedge pulley).

Compared with cast iron belt pulley, spinning belt pulley has the advantages of adopting spinning process (no chip processing), light structure, material saving, and small moment of inertia. It is a new product with material saving and energy saving. High production efficiency (processing 2~4 pieces per minute), good balance performance, generally without balance treatment. As the material streamline is not cut off, the surface is cold worked and hardened, and the organization density is increased, the strength and hardness of the wheel groove surface are improved, and the size accuracy is high, the slip between the V-belt and the wheel groove is small, and the belt life is long. (Screw the belt pulley and starter housing)