It mainly consists of outer curved aluminium alloy hollow sheet, roller, tilting wheel and mandrel.
Three groups of curved aluminium alloy hollow sheets are arranged on the surface of the roller, one group in the middle is fixed on the roller, and each group on both sides is inlaid in the aperture groove of the roller, and the ends are connected to the outwardly tilting rotating wheels on both sides. When the sheet follows the roller body to rotate the sheet drives the tilting wheel to rotate, and the tilting wheel drives the sheet outward and inward for reciprocating movement. The sheet moves outward when it turns from 0 to 180 and backward when it turns from 180 to 360. When the substrate wraps around the sheet in 0-180, it is stretched axially by the outwardly moving sheet and can be flattened.