METHOD FOR MANUFACTURING A PLUG-TYPE CHAMBER USED IN THE CASCADE DRAWING OF TUBES, AND DEVICE FOR IMPLEMENTING THE METHOD

摘要

A method and apparatus for manufacturing a plug-type chamber to accommodate at least two floating plugs for use in the cascade drawing of tubes are disclosed. A starting tube is first fixed in position by a clamping and denting device. A necking-down ring is subsequently moved with the help of a necking-down cylinder along a freely projecting end section of the starting tube. A punch is then pushed with the help of a cylinder into the end section of the tube. When the punch has reached its end position, the necking-down ring is pulled over the end section of the tube, and the outside diameter is reduced to its original size. The punch is subsequently removed, and two indentations are made on the periphery of the end section of the starting tube with the help of the clamping and denting device. Together with a drawing point produced through the reshaping of the unattached end of the starting tube, these indentations then form a plug-type chamber, in which several floating plugs are embedded, which interact with drawing dies during the cascade drawing operation.