... material and is widely used as the external packing for food, drink, tea, glasswork, handiwork, sanitaryware, ... a head, an upper tractor for rotation, a cooling device, a heating device for expanding, a coiling device ... controlling system. 2.The set adopts the upper tractor for 360°continuous rotation, which is more stable ... film is coiled flatter. Due to the upper tractor, the work of cleaning the screw ...