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. There are a couple of ways of how the spinning may be done such as CNC lathe or by hand. Metal spinning normally consists of the removal of material like in traditional metal or wood turning. However, forming or molding of sheet material is over an 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.
Commercial applications for metal spinning process is quite a lot and this includes rocket nose cones, cookware, gas cylinders, brass instrument bells, public waste receptacles and so forth. Fact is, any ductile metal can be formed from stainless steel, aluminum to high strength and high temperature alloy. As for the diameter and depth of the formed parts, these are limited by the equipment’s size.
For the spinning process, it is basically simple, in the drive section of lathe, a formed block is being mounted and pre-sized metal disk will be 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. Usually, the force is being applied through different levered tools. Simple workpieces are being removed from block however, several blocks may be required for more complex and sophisticated shapes.
When working with extremely complicated shapes, it is spun on ice forms that 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 the surface form and finish aren’t that critical, then the workpiece is being spun on air and no mandrel has to be used. If the form or finish is hard however, it will demand eccentrically mounted mandrel.
Throughout forming process, metal spinning tools are allowed in the bearings. These tools are used to be able to reduce heating and friction of the tool, extend its life while also improving surface finish. To be able to extend the life of the tool, the rotating tools are coated using thin film of ceramic.