It is well known that traditional spinning is used to make lampshade shells, tableware and other containers. The main feature of this type of product is that the thickness of the metal being spun is very thin, making it suitable for manual spinning operations. With the development of numerical control spinning, CNC spinning has been more widely applied in other fields.

 

Why the automotive industry require metal spinning＞

 

Automobile parts are also the industry with the largest application of spinning technology. According to the latest industry report analysis, the spinning industry's market in the automotive sector is as high as over 20 billion dollars. Unlike the application of lamps and tableware, automotive parts basically have mechanical functional requirements, including dimensional accuracy, material mechanical properties, and mechanical load requirements. The application of numerical control spinning perfectly fills the gap of traditional hydraulic forming, hot forging, hydraulic expansion forming, etc. Compared with these traditional processes, the products after flow forming spinning have higher precision and better strength, and can meet the lightweight requirements of automobiles.

 

 

1. Automotive wheel hub manufacturing

 

Manufacture craft ：Casting + metal spinning

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The spinning process enhances strength and reduces weight by subjecting the rim area to high-speed rotational extrusion on the basis of the casting blank, making the metal molecular structure more compact. Compared with traditional cast wheels, spun wheels can reduce weight by 15% to 20%, have a strength close to that of forged ones, but their cost is only about 50% of the latter. The spun parts are close to the final size, with excellent dynamic balance performance, reducing subsequent machining processes and improving production efficiency. They have become the mainstream choice for mid-to-high-end models and the modification market. 

 

 

Hub spinning machine

 

Currently, among the global manufacturers of automotive wheel hub spinning equipment, the well-known ones include Leifeld and WF from Germany, MJC from the United States, and DENN from Spain. These are all traditional spinning brands. Now, China's automotive industry is developing rapidly in the field of new energy. The earliest companies to research and design wheel hub spinning machines are Okay and Prosper. However, the market response was the best, sales were high, and the most widely used were still Denlis's automotive wheel hub spinning machines and matte machines.

 

 

Good hub wheel spinning equipment

 

The investment in an automatic production line for car wheels is extremely expensive. The degree of automation of car wheels is very high. Once the machine production is unstable, it will cause great losses. At present, the technology of hub spinning machines has become quite mature. For instance, companies like Leifeld from Germany, MJC from the United States, and DENN from Denmark have been developing and manufacturing spinning hub machines for many years. In recent years, with the rapid development of new energy vehicles in China, the technology of China's spinning equipment has also been greatly improved. Companies like Aoken, Bosai and Dingli have all developed spinning hub machines. Among them, Dingli Spinning enjoys the highest recognition in the automotive industry, has the largest sales volume of equipment, and its production is also more challenging.

 

Recommondations for Hub spinning equipment manufacturer

 

DENN   MJC   Dienlis   Okay   Prosper

 

2. Air spring＞

 

Manufacture craft : hydroform + metal spinning

 

 

Most air shock absorbers are used in luxury cars, Air is an elastic medium. Compared with steel springs, the elastic curve of air springs is gentler, and they filter out small bumps more thoroughly. The pursuit of a "floating sensation" in luxury cars mainly relies on air springs. Common air spring of the automobile includes those for Audi A3, A6,A8, BMW 3 Series, 5 Series, 7 Series, Mercedes-Benz C Series, E Series, Tiguan, Panamera, etc.

 

Material selection for automotive parts

 

The aluminum materials commonly used for automotive shock absorbers are 5052 and 6061 aluminum. Among them, 5052 aluminum has the best tensile strength among civilian aluminum materials, while the hardness of 6061 material is the best in the T6 state.

 

Although 1060 and 3003 aluminium materials are easier to spin and form, the tensile strength and hardness of the final formed products are slightly inferior to those of 5052 and 6061 aluminium, and the mechanical comprehensive performance of the obtained products is also slightly inferior.

 

Processing technology

 

The metal casing of the air shock absorber is mainly made of steel, 409 or 430, and aluminum through metal forming. The main processing techniques include aluminum extrusion, deep drawing, water swelling and metal spinning.

 

In most of the processing and manufacturing of automotive shock absorber housings, most parts need to be made into a rough blank by hydroforming, water expansion or aluminum extrusion first. This can greatly avoid the problem of low processing efficiency of spinning production. Then, the prefabricated rough blank is subjected to secondary necking or expanding on the spinning machine, which greatly utilizes the flexibility of the spinning manufacturing curve.

 

The benefits of metal spinning

 

After spinning, the pores and sand holes in the raw materials will be reduced, the air tightness is better. The hardness and tensile strength of the shell have been greatly enhanced. At the same time, the CNC metal spinning machine＞ has the function of CNC turning processing. The shell of the air spring tube that originally needed to be spun and then undergo secondary CNC turning processing can be directly turned after being formed by the CNC spinning machine, without the need to change fixtures, and the concentricity is higher.

 

The tolerance

 

The precision of the shock absorber housing can reach up to 0.1mm after spin forming

 

3. Three-way catalyst

 

The shapes of three-way catalytic converters can be either non-axially symmetrical or axially symmetrical.

 

Metal spinning vs traditional welding

 

Metal spinning is mainly used for processing three-way catalytic converters with axially symmetrical structures. Three-way catalytic converters are generally formed by spinning tubes. Compared with traditional processes, spinning reduces the welding at both ends through necking, resulting in higher dimensional accuracy and lower costs during processing. The integrated manufacturing of complex curved surfaces is achieved through spinning forming, avoiding welding stress concentration and enhancing high-temperature resistance and fatigue resistance.

 

Production efficiency

 

The time for spinning to produce a three-way catalytic converter is generally 2 to 4 minutes. Compared with the traditional process, it has a higher processing efficiency and a lower raw tea cost.

 

Welding of the blank tube

 

The tubes of a three-way catalytic converter usually need to be welded into round tubes. If there are problems with the manufacturing process of the round tubes, they are prone to cracking during the process of compressing the joints. So when welding round pipes, the following two issues need to be noted. First, the rough blank material of the round pipe should be made of forming materials as much as possible. If 304 is used for spinning, 304DDQ should be selected. Second, it must be completed by automatic welding. Manual welding is prone to causing areas with missed welds and false welds, and these areas are very likely to crack.

 

4. Pulley

 

 

Metal spinning pulleys are lighter than traditional castings, which helps to reduce the overall fuel consumption of the vehicle or increase the driving range of electric vehicles.

 

The metal fiber streamline is continuous, the grains are refined, and the mechanical properties are superior to those of ordinary castings, with the impact resistance increased by approximately 30%.

 

The material has a high density, the surface hardness of the wheel groove is enhanced, the slip between the V-belt and the wheel groove is small, and the service life of the belt can be extended by more than three times

 

The material utilization rate exceeds 90%, and there is no cutting waste in the production process.

 

5. Hydrogen cylinder

 

The third-generation hydrogen cylinders now use an aluminum inner, and the outside is fully wound with carbon fiber. It is mainly used for city buses, heavy-duty trucks, long-distance freight vehicles, forklifts and tractors.

 

Hydrogen tank metal spinning＞

 

Hydrogen cylinder spinning machines are different from the common sheet metal spinning machines. They belong to tube spinning and necking spinning machines. The spindle of a hydrogen cylinder spinning machine must have a mechanism for clamping tubes, and the tailstock is generally designed with an automatic heating device. During the spinning process, after the blank is heated, the fluidity of the aluminum material is better, the thickness of the mouth after spinning increases more, and the feed speed of the spinning forming can also be faster.

 

 

Advantage

 

The advantages of the third-generation hydrogen cylinders are good air tightness, resistance to permeability, impact and vibration.

 

 

6. Truck fuel tank

 

The fuel tank of a truck is generally made by welding two heads together.

 

Head metal spinning

 

Compared with the traditional hydraulic forming, the mold cost of the spinning head is lower, and it has more advantages for customizing heads with many specifications and small production quantities.

 

Welding and air pressure testing＞

 

The fuel tank generally has requirements for air tightness. After the overall welding is completed, it needs to be used in the water tank for air pressure detection. When detecting the air pressure, if the pressure directly output by the factory's air compressor is too high, it is easy to cause the product to crack or deform, making the test unsafe. Generally, the pressure of the air compressor needs to be reduced first, and the input pressure of the product is controlled by connecting a pressure reducing valve. The pressure reducing valve can be spun by the Japanese SMC brand, which is of good quality and durable.