Tube drawing with plug - with lubricant undercut

摘要

In the drawing operation the workpiece tube is firstly reduced in dia. round a cylindrical portion of a multiazone plug by passage through a pre-forming die, this being followed by reduction to its final dia. and wall thickness between the second working portion of the plug and the drawing die. The prefd. design has an undercut between its two working sections in which lubricant is built up, which has been injected into the tube and which is compressed during drawing by the workpiece tube exercising hydrodynamic lubrication permitting large reductions in area.