Hot Spinning in Metal Working Process

Parts that have circular cross-sections can be made by spinning them from sheet metal. The principle of metal spinning. A heated circular blank of sheet metal is lightly held against a chuck by the pressure of a freely rotating pad on the lathe tail stock. This chuck may be made of plaster, wood or metal and is revolved on the spindle of a lathe. A rounded stick or roller is pressed against the revolving piece and moved in a series of sweeps. This displaces the metal in several steps to conform to the shape of the chuck. Once the operation is started, considerable frictional heat is generated which aids in maintaining the metal at a plastic state,

Spinning is a highly specialized art. To avoid excessive thinning of the metal, the pressure of the forming tool (rounded stick) should be directed sometime backward toward the tail stock as well as forward toward the head stock. During "spinning on air" (not against the chuck), with large parts made from relatively thin metal, a hardwood bar is commonly used as a back-up support opposite the spinning tool to avoid wrinkling at the outer edge.

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Mechinopedia For Mechanical Engineers

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