The characteristics of CNC spinning processing are that it is suitable for small and medium-sized batch production, processing materials with thick wall thickness, large forming stretching length, medium processing accuracy, and thin-walled parts of rotating bodies with complex shapes.

Compared with CNC spinning, manual spinning technology is limited by manpower and cannot process thicker spinning products. When stamping and stretching process processes hardware forming products of the same thickness, the processing force required is 3-5 times that of spinning. Therefore, stamping and stretching require a large tonnage punch or hydraulic press when processing aluminum with a thickness of more than 4mm, 2mm stainless steel, and 3mm iron. When the product is mass-produced, the speed of stamping and stretching forming will be faster than CNC spinning, and the unit cost will be lower. For products with a large stretching length, stretching and stamping forming is prone to cracking, and the forming time of a single product by spinning is very long. Usually, semi-finished blanks are made by hydraulic stretching, and then spinning is used for final forming. The combination of the two processes can greatly improve the production efficiency of the product and reduce the scrap rate of the product. Aluminum and iron products are easy to combine spinning and stretching. Due to the high hardness of stainless steel, the stretch-formed blank is easy to crack at the position of the spinning joint, as shown in the figure.

The idling accuracy of CNC spinning machine tools is 0.04mm. Due to the influence of material flow and stress rebound during the spinning process, the accuracy of the processed products cannot reach 0.04mm. Among the three materials of aluminum, iron and stainless steel, the accuracy of stainless steel spinning products is the most difficult to control. Taking the diameter of 100mm as the benchmark, the diameter accuracy of general aluminum spinning parts can reach 0.1mm, the diameter accuracy of iron is about 0.2mm, and the diameter accuracy of stainless steel is about 0.4mm. The larger the diameter of the product, the worse the accuracy. The accuracy of strong spinning is higher than that of general spinning. When the spinning product has assembly accuracy requirements, it can be achieved through fine turning. At present, the product series widely used in CNC metal spinning include lampshades, stainless steel bowls, stainless steel pots, shielding covers, signal reflective covers, signal receiver covers, chemical containers, power containers, aluminum barrels, stainless steel barrels, venturi tubes, fan vents, ventilation ducts, funnels, electrical liner, motor protective covers, etc. CNC spinning process is more suitable for such special customized and small and medium batch products.

Differences and advantages of CNC spinning and manual spinning

CNC spinning and manual spinning have the same movement principle in the product forming process. The tail top provides clamping force to drive the sheet to rotate with the spindle. The cutter wheel extends the sheet from point to line and from line to surface according to the predetermined cutter path route to complete the forming. The difference is that CNC spinning controls the path of the cutter wheel during the spinning process and the gap between the cutter wheel and the mold. Due to the high operating accuracy, good equipment rigidity and large processing force of CNC machine tools, the manufactured products have good consistency, stable production, and can well control the accuracy of the products; while in the manual spinning process, the cutter rod is manually controlled to determine the cutter path of the cutter wheel. The cutter path and gap between each product are different, resulting in unstable precision of batch products.

When the thickness of the spinning sheet exceeds a certain range (iron exceeds 1.2mm, aluminum exceeds 1.5mm, and stainless steel exceeds 1mm), manual strength cannot support the processing force required for spinning, which can easily cause the product to be scrapped. When manual spinning and spinning die manufacturing is used to make thin aluminum and iron products, the outer wall surface of the processed product will be better than that of CNC spinning. However, after continuous improvement of process technology in CNC spinning in recent years, the outer wall surface of the spinning product has been very similar to that of manual spinning.

The difference and advantages of spinning and stamping and stretching

Both spinning and stamping and stretching can form the sheet. The specific differences and advantages are as follows:

Principle difference: Spinning is controlled by the path of the knife wheel to control the flow and deformation of the sheet, while the stretching and stamping process is to control the flow of the sheet through the cooperation of the upper and lower convex and concave dies.

Difference in molds: To make the same hardware forming product, metal spinning only needs to make one core mold, while stretching and stamping need to make two convex and concave molds. The manufacturing cost of the mold is usually 3-6 times that of spinning. At the same time, the manufacturing cycle of the spinning mold is shorter than that of the stretching and stamping mold, and the size is easier to modify.

Difference in materials: The thinning rate of spinning processing is usually about 30%, and the thinning rate of stretching and stamping processing is about 10%, which is relatively larger. Stretching and stamping require a 5-10mm edge material, and the required material cost is higher.

Difference in processing: For some simple hardware forming products, stretching and stamping forming processes are more, including basic processes such as cutting, forming, and trimming. Some products need to go through multiple stretching processes during the forming process. The processes are numerous but the processing speed is relatively faster. Spinning and cutting can be completed on a CNC spinning machine at the same time, but the processing speed of a single piece will be slow; for some products with long stretch height or special shapes, stretching and stamping will cause product cracking, but spinning is easier to complete product forming.

Product differences: In terms of the surface of the product, the spinning marks are distributed in circles, and the stretch marks are distributed in vertical lines; in terms of the strength of the product after forming, the strength of the spinning product will be much better than that of the stretching and stamping product.