Metal spinning is a niche metal-forming technique that lives at the juncture between medieval craft and high-tech aerospace applications. Spinnings play a lead role in some of our most beautiful products, but choosing the right application is both complex and crucial.
Spinning, by and large, produces metal objects that are axially symmetrical, rounded, and hollow. Unlike solid turnings, where one takes a piece of solid metal and carves away material to reveal something inside, spinnings appear to be like solid, lathe-turned objects, but are actually hollow formed sheet metal. The process is performed on a specialized, robust lathe and starts with a round, metal disc pressed against a solid pattern, called a mandrel. The lathe is then switched on and the tool and metal sheet spin together rapidly. Force is applied to the spinning blank using polished-nose tools. The spinning action distributes the forming energy symmetrically, and the sheet metal flows over and envelopes the mandrel, taking its exact contours.
For shapes that curve back in on both sides, known as re-entrant shapes, a collapsible or multi-piece mandrel must be used so that the mandrel is not captured and can be removed after spinning. An example of such a shape is the Winston Chandelier’s potbelly body, shown below.
The beauty and value of metal spinning rest in its ability to generate beautiful and large parts quickly, precisely, and efficiently. There are no theoretical upper size limits to this process: large sheets can be welded together, huge forms can be made. The same shapes produced via casting or solid lathe turning would be both impossibly heavy and needlessly expensive.
Selecting the right type of spinning for the volume, dimensions, and details of the job is a complex calculation, and one of the steps where our expert team provides lasting value. Contact our Custom Division to get started.