① The entrance area and lubrication area are combined into one, which has a tendency to reduce the lubrication angle, so that the lubricant is subjected to a certain pressure before entering the working area, thereby achieving a better lubrication effect.
②The entrance area and working area are lengthened to establish a better lubrication pressure, and the angles are optimized according to the drawing material and the compression rate of each pass.
③The sizing area must be straight and reasonable in length.
④The vertical line of each part must be straight.
