Metal spinning or otherwise known as spinning, spin forming or metal turning is a process of metalworking by which a tube or disc of metal is being rotated at high speed and form into axially symmetric part. Spinning can be done as well by either a CNC lathe or by hand. Most of the time, the process of metal spinning involves the elimination of material 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 are using this process in order to produce architectural detail, decorative household goods as well as urns and 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. Basically almost any type of ductile metal can be formed form aluminum or stainless steel to high strength and high temperature alloys. But you should know that for the diameter and depth of the formed parts, this will be limited only to the size of equipment.
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. At high speeds, the block and the workpiece are being rotated together. To make it flow to block, a local force is applied to workpiece. Normally, the force applied is through the use of different levered tools. Simple workpieces are removed from block but there are more complex shapes that require several blocks.
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.
When it comes to more complicated procedures, it’s otherwise called as necking or reducing that allows the spun workpiece to use 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 for example that the form or finish is critical, then it will require eccentrically mounted mandrel.
There are also the metal spinning tools allowed on bearings throughout forming process. 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.