Pulished on Mar. 05, 2020
I. Features of CNC Spinning
CNC spinning is suitable for thin-walled rotating body parts with medium and small batch production, large wall thickness of processing materials, large drawing and stretching length, medium processing accuracy, and complex shapes.
Compared with CNC spinning, manual spinning technology is limited by manpower, so it is impossible to process spinning products with a large thickness, and the stamping and drawing process requires 3 times the processing force when processing metal forming products with the same thickness. -5 times, so punching and stretching requires a large tonnage punch or hydraulic press to process aluminum with a thickness of more than 4mm, stainless steel with 2mm, and iron with 3mm. When the product is mass-produced, the speed of stamping and stretch forming processing will be faster than CNC spinning, and the unit price will be lower. For products with a large stretch length, stretch stamping is easy to crack, and the forming time of a single product using spinning processing is very long. Generally, the semi-finished product blank is first produced by hydraulic stretching, and then the final molding process is performed by spinning. The combination of these processes can greatly improve the production efficiency of the product and reduce the scrap rate of the product. Aluminum and iron products are easily combined with spinning and stretching. Due to the high hardness of stainless steel, the stretched blank is easy to crack through the position of the spinning joint, as shown in the figure.
The dry running accuracy of the CNC spinning machine is 0.04mm. Due to the influence of material flow and stress rebound during the spinning process, the precision of the processed product cannot reach 0.04mm. Among the three materials of aluminum, iron and stainless steel, the precision of stainless steel spinning products The most difficult to control. Based on the diameter of 100mm, the diameter accuracy of 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 accuracy is higher than that of the ordinary spin. When the spinning parts require assembly accuracy, the requirements can be achieved by precision turning. At present, the product series widely used in CNC spinning are lampshades, stainless steel bowls, stainless steel pots, shields, signal reflectors, signal receiver covers, chemical containers, power containers, aluminum barrels, stainless steel barrels, venturi tubes, fan vents, Ventilation pipes, funnels, electric appliances, motor protective covers, etc. The CNC spinning process is more suitable for such special customized, small and medium batch processing products.
II.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 clamping force is provided by the tail top to drive the blank to rotate with the spindle. The cutter wheel allows the blank to move from point to line and Line-to-face extension, and finally forming. The difference lies in the CNC spinning, which is controlled by the CNC machine tool during the spinning forming path, and the gap between the cutter wheel and the mold. Due to the high accuracy of CNC machine tools, good equipment rigidity and high processing power, the manufactured products have good consistency, stable production, and can control the accuracy of the products; while in the process of manual spinning, manual control of the knife The tool path is determined by the lever, and the tool path and clearance between each product are different, which results in unstable batch product accuracy.
When the thickness of the spinning material exceeds a certain range (iron exceeds 1.2mm, aluminum exceeds 1.5mm, and stainless steel exceeds 1mm), artificial force cannot support the processing force required during spinning, which may easily cause product scrap. When manual spinning is used to make thin pieces of aluminum and iron products, the surface of the outer wall of the processed product will be better than the surface of CNC spinning. However, after the continuous improvement of process technology in recent years, the outer wall surface of the spinning products has been very similar to manual spinning.
III.Differences and advantages of spinning and stamping
Both spinning forming and stamping and drawing forming can form the sheet. The specific differences and advantages are as follows:
The difference in principle: Spinning molding is to control the flow and deformation of the blank by the path of the cutter wheel, while the drawing process is controlled by the cooperation of the upper and lower convex die.
Mold difference: To make the same metal forming product, only one core mold is required for spinning molding, and two convex and concave molds are required for stretch stamping. The manufacturing cost of the mold is usually 3-6 times that of spinning. The manufacturing cycle of the mold is shorter than that of the drawing die, and the size is easier to modify.
Material difference: The thinning rate of spinning is usually about 30%, the thinning rate of stretching and pressing is about 10%, and the thinning rate is relatively large, while the blanking of stretching and stamping requires about 5-10mm. The cost is bigger.
Processing differences: For some simple hardware molding products, there are many drawing and stamping forming processes, including basic processes such as blanking, forming, and trimming. Some products need to be stretched multiple times during the forming process. The processes are numerous but the processing speed is relatively faster. Spin forming and cutting can be done 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 or special drawing height, stretch stamping will cause product cracking, but spinning Easier to complete product molding.
Product difference: On the surface of the product, the spinning pattern is distributed in a circle, and the stretch marks are distributed in a vertical line. In terms of the strength of the product after molding, the strength of the spinning product will be much better than the strength of tensile stamping.
