| 摘要 |
PURPOSE:To minimize the number of pressing winds of a lapper roll, and to reduce an overlap flaw of a coil by providing a holding and an excess expansion on an expansion stage of a mandrel, ending the excess expanding operation before the mechanical expansion limit, and simultaneously, opening said roll. CONSTITUTION:When winding a strip S by using a mandrel M for executing a reduction and an expansion, and a lapper roll R provided on the outside circumferential part of the mandrel M, a holding and an excess expansion are provided on an expansion stage of the mandrel M, a holding expansion diameter before starting to wind the strip S, and an excess expansion speed executed in a stage in which the strip S is wound to the mandrel M and wound in a shape of a coil are adjusted, the excess expanding operation is ended before the mechanical excess expansion limit of the mandrel M, and simultaneously, the lapper roll R is opened. In this way, the number of coil pressing winds of lapper roll is set to the necessary minimum, and an overlap flaw generated on the inside surface of the coil can be reduced.
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