Metal spinning comes by different name from metal turning, spin forming or spinning; this is a process of metalworking to which the tube or disc of metal is rotated at high speeds in order to form it into axially symmetrical 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. On the other hand, forming or molding of sheet material is done over existing shape.
Actually, metal spinning is ranging from the artisan’s specialty to the most sophisticated way of forming round metal parts primarily for commercial applications. As a matter of fact, artisans are utilizing this process as a way to generate architectural detail, decorative household goods as well as urns and specialty lighting too.
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. 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. At high speeds, the block and the workpiece are being rotated together. Local force is applied in the workpiece in order to make flow to the block. 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.
When working with extremely complicated shapes, it is spun on ice forms that melts after spinning. Since the final diameter of workpiece is less than its starting diameter, the workpiece has to be elongated radially, thickened or buckled circumferentially.
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 for example that the surface form and the finish is not that hard, the workpiece is spun on air and no mandrel ought to be used. If for example that the form or finish is critical, then it will require eccentrically mounted mandrel.
There are metal spinning tools that are allowed on the bearings throughout the 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.