Metal forming have many process methods and technologies. Common metal forming includes  metal spinning, deep drawing, rolling, aluminum forging, stamping, water expansion. Every craft have its advantage and character, metal spinning plays an irreplaceable role in the industry, except metal spinning mold cost is cheap and lead time is short, the important is the tolerance and surface of metal spun products are well, the hardness and tensile strength are improved after cold pressing by metal spinning. This article will introduce the metal spinning advantage and disadvantage.

The advantage

1.Good metal deformation conditions and less forming force : the contact area is small between the rotary roller (wheel) and work piece in metal spun process, the unit pressure of blank metal is high when is pulled and pressed by roller, so it is suitable to process high-tensile strength materials that are difficult to deform. Processing the same size of the work piece, the tonnage of the metal spinning machine only needs to be about 1/20 of the tonnage of the hydroforming (deep drawing).

2.Process and forming ability : The range of metal spinning products is very wide, according to the ability of metal spinning machine to produce large-diameter thin-wall pipe, special pipe, variable section pipe and spherical, hemispherical, oval, curved bus shape and almost all rotary system parts with ladder and changing wall thickness. Compared with hydroforming and water  expansion, metal spinning can process complex and challenging shape, thicker thickness, harder metal.

3.High blank material utilization and low production cost : metal spinning is a process that produces almost no waste material, trimming scrap is about 1% of the blank material. Compared with CNC turning machining, metal spinning processing can save about 70% of materials, which greatly reduces the raw material cost of enterprise production. Compared with deep drawing (hydroforming), metal spinning diameter is about 80% of deep drawing.

4.Less mold cost and adjusting easily : all of metal forming technology need molds, the mold cost of deep drawing and water expansion are 3-5 times of metal spinning mold. On the other hand, metal spinning mold is easy to adjust the size when the customer change the design drawing, it can be repaired in the CNC metal spinning machine directly, deep drawing and water expansion mold need to scrap part of mold to achieve the drawing change.

5.Short sample period : metal spinning mold is just a mandrel that the exterior curve of mold is same with the interior curve of metal spinning product, mold is mainly processed by CNC turning, lead time is short, so the sample period is short.

6.High quality of finished products : After spinning, the internal structure of the metal material changes, the material grains have fibrous characteristics, and the arrangement is closer, the tensile strength and hardness of the product are greatly improved. the sand holes and pore of blank sheet will reduce or remove after metal spinning roller pressing, when you polish the pressing surface of metal spinning, it can achieve the 8K mirror without sand holes and pore.

When you test the same thin and shape that made by metal spinning or other processing method in high temperature, you will found that tensile strength and rigidity of metal spinning reduction is least in high temperature or poor working condition. This is the reason why metal spinning components are applied in aerospace widely.

7.Low surface roughness of the finished product, small dimensional tolerances : Spinning processing can achieve high accuracy, the movement trajectory of the metal spinning roller (wheel) can be accurately controlled by CNC system, so the dimensional error of the machined parts is minimal. The most important effect of metal spinning tolerance is the metal spring back of different metal after spinning.

The interior surface of spun product is smooth when the mold surface is polished, the exterior surface has uniform spinning line. Except the exterior surface of deep drawing product is better than metal spinning, the precision casting is worse than metal spinning.

8.The finished product has good integrity that is seamless : Compare to rolling and welding cylinder or cone, when you test metal spinning container by air pressure in the water tank, the bearing capacity and air tightness are very good.

9.Less process step : The spinning process step, it can finish metal spinning forming, trimming, hemming in a mold and machine, but deep drawing and water expansion need more steps by different mold and machine, so metal spinning needs less labor to feed and blank.

10.Wide source of blank materials : The materials that can be spun are aluminum, copper, stainless steel, iron, aluminum alloy, etc., and even can form the hard and poor ductility metal by heating. Such as the high - tensile strength aluminum 5A06, Aircraft aluminum series 2024 and 7075, the hardest steel (Hardox series), the high temperature alloy applied in combustion chamber, the aircraft nozzle material ( Inconel 718 and Inconel 625, nickel base alloy), the high  hardness and wear resistance stainless steel (SUS630), these material are hard to form by traditional machining and forming. Only hot spinning is the better solution for hard metal forming.

The disadvantage

1.Metal spring back is big : even though metal spinning forming path is controlled by CNC system like CNC turning, spun forming has big spring back, so it’s tolerance is worse than CNC turning, commonly the CNC turning tolerance can achieve 0.02mm, but metal spinning tolerance can achieve the 0.2mm at most when it is removed from mandrel, it is soft and elliptical deform as the spring back.

Metal spinning tolerance is similar with deep drawing, water expansion, aluminum forgetting. All the metal forming have internal stress after cold working and pressing, but the spring back of metal spinning is biggest.

How to control the metal spinning accuracy ＞＞

2.Production efficiency : The machining time is slower than hydroforming, water expansion, aluminum forging, the production efficiency only have 1/4 -1/2 of other metal forming machining. so the unit price of metal spinning is more expensive than other metal forming machining.

The conclusion 

The advantage of metal spinning  is obvious, it mainly includes high hardness and tensile strength, cheap mold, short lead time, smooth surface, high accuracy, design adjustment easily. It is  suitable to make the big dimension, customized product with smaller quantity of order, equipment components, aerospace core components, hard metal forming of metal forming product. 

If you want to know more metal spinning product, you can read this article＞＞