20140102158 | METHOD OF TUBE-NECKING SPINNING AND APPARATUS THEREFOR - A two-step method and apparatus therefor provide cost-effective processing of tube-necking spinning for Superconducting Radio Frequency (SRF) cavities. A metal tube as a work piece may be rotated round its longitudinal axis; the target shape is obtained gradually in two steps by driving specially profiled rollers along roller paths moving in radial and axial directions. Alternatively, the rollers may rotate around a stationary work piece. To spin one cell, in the first step, a primary forming roller moves along a roller path to form a partial necking shape; then, in a second step, a secondary forming roller moves along a roller path to continue necking processing; and finally, the full cell is formed. To spin multi-cells, this two-step method is repeated for each cell. No additional equipment is required as rollers are mounted the same as in conventional spinning The cost is reduced by applying a rapid feeding rate, greatly shortening the length of the roller path, accurately controlling the spun profile and eliminating a complicated mandrel. | 04-17-2014 |