Metal spinning or also called as spin forming, metal turning or spinning is the process of metalworking to which a tube or disc of metal rotates at high speed and then, form into axially symmetrical part. Spinning can be done as well by either a CNC lathe or by hand. Metal spinning involves the removal of material as in traditional metal or wood turning. As for the molding or forming of sheet material, it’s done over existing shape.
In reality, metal spinning range from the expertise and experience of the artisan up to the most complicated and beneficial way to form round metal parts for commercial purposes. Artisans use this process to be able to produce architectural detail, decorative household goods as well as urns or even specialty lighting.
For commercial applications of metal spinning process, it’s plentiful actually similar to production of cookware, gas cylinders, rocket nose cones, brass instruments, public waste receptacles and so forth. Virtually, any kind of ductile metal could be formed from stainless steel or aluminum to high temperature, high strength alloys. Both the depth and diameter of formed parts are only limited by the size of available equipment.
Spinning process is fairly simple; in drive section of the lathe, formed block is mounted and pre-sized metal disk is clamped against the block with the use of pressure pad that’s attached to the tailstock. The block and workpiece are rotated together at fast speeds. Localized force is applied to workpiece to make it flow to the block. Oftentimes, there are different levered tools used in applying force. Simple workpieces are being removed from block however, several blocks may be required for more complex and sophisticated shapes.
As for extremely complicated shapes, it can be spun on ice forms which melts after spinning. Because the final diameter of workpiece is less than the starting diameter, the workpiece ought to be thickened, buckled circumferentially and elongated radially.
For the more involved procedures, it’s referred to necking or reducing, it allows the spun workpiece to incorporate reentrant geometries. If for instance that the surface form and finish are not critical, the workpiece is spun on air and no mandrel needs to be used. If the form or finish is hard however, it will demand eccentrically mounted mandrel.
There are metal spinning tools that are allowed on the bearings throughout the forming process. These tools help in reducing heating and friction of the tool, extending its life while improving the surface finish. To be able to extend the life of the tool, the rotating tools are coated using thin film of ceramic.