MILL COMPOSED OF POLYGON CONE ANGLE SPIRAL BOARD

The utility model relates to a mill composed of polygon cone angle spiral board, comprising a mill cylinder, backings and an ordinary backing screw bolt. The utility model is characterized in that penta, hexagon, heptagon or octagon assembly surrounded by the backings is fixed on the inner wall of the mill cylinder; the neighbouring two backings are a group in the mill cylinder, the previous backing is flat pattern and the rear one is hierarchical conical surface; the relative rotation angle between the neighbouring two backings is 15 DEG-45 DEG and the cone angle between each backing is 8 DEG-20 DEG, and toroid furrow and corrugated tank are respectively arranged on each backing surface.