METALSPINNING is a term used to describe the forming of metal into seamless, axisymmetric shapes by a combination of rotational motion and force (Ref 1–4). Metal spinning typically involves the forming of axisymmetric components over a rotating mandrel using rigid tools or rollers. There are three types of metalspinning techniques that are practiced: manual (conventional) spinning (Ref 1, 2), power spinning (Ref 4–11), and tube spinning (Ref 7, 8). The first two of these techniques are described in this article. Tube-spinning technology is described in the articles “Flow Forming” and “Roll Forming of Axially Symmetric Components” in Metalworking: Bulk Forming, Vol 14A of ASM Handbook, 2005. Figure 1 shows examples of products from metal spinning. The range of components include:
- Bases, baskets, basins, and bowls
- Bottoms for tanks, hoppers, and kettles
- Canopies, caps, and canisters
- Housings for blowers, fans, filters, and flywheels
- Ladles, nozzles, orifices, and tank outlets
- Pails, pans, and pontoons
- Cones, covers, and cups
- Cylinders and drums
- Funnels and horns
- Domes, hemispheres, and shells
- Rings, spun tubing, and seamless shapes
- Vents, venturis, and fan wheels
The equipment for metal spinning is based on lathe technology, with appropriate modifications for the components that are being formed. Typically, sheet preforms are employed to allow relatively low forming stresses. Metal spinning can be used to cost-effectively produce single or a small number of parts out of expensive materials, such as platinum, or large quantities of components of low-cost materials, such as aluminum reflectors. In this article, the term preform is used to describe the component both before and during metal spinning; other terms that are sometimes used include workpiece and starting blank. In manual spinning, a circular blank of a flat sheet, or preform, is pressed against a rotating mandrel using a rigid tool (Ref 1, 2). The tool is moved either manually or hydraulically over the mandrel to form the component, as shown in Fig. 2. The forming operation can be performed using several passes. Manual metal spinning is typically performed at room temperature. However, elevatedtemperature metal spinning is performed for components with thick sections or for alloys with low ductility. Typical shapes that can be formed using manual metal spinning are shown in Fig. 3 and 4; these shapes are difficult to form economically using other techniques. Manual spinning is only economical for lowvolume production. Manual metal spinning is extensively used for prototypes or for production runs of less than ~1000 pieces, because of the low tooling costs. Larger volumes can usually be produced at lower cost by power spinning or press forming. Power spinning of metals and alloys is also known as shear spinning (Ref 4–11), because this forming method employs high shear forces. There are two large-volume applications of power spinning: metal cone spinning and metal tube spinning. Power spinning can also be employed to produce hemispheres, provided a preform of the appropriate design is employed. In cone spinning, a flat blank or metal sheet is deformed over a mandrel at high speed.
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