Sizing cylinder for improving production quality of heat shrink tube

The utility model discloses a sizing cylinder for improving the production quality of a heat shrink tube, and relates to the technical field of heat shrink tube production, the sizing cylinder comprises an outer-layer aluminum tube and an inner-layer aluminum tube, the inner-layer aluminum tube is arranged in the outer-layer aluminum tube along the axial direction, and a central hole of a baffle ring is communicated with an inner cavity of the inner-layer aluminum tube; a cooling water channel is defined by the outer wall of the inner-layer aluminum pipe, the inner wall of the outer-layer aluminum pipe and the two baffle rings, a water inlet pipe communicated with the cooling water channel is fixedly arranged at one end of the outer-layer aluminum pipe, and a water outlet pipe communicated with the cooling water channel is fixedly arranged at the other end of the outer-layer aluminum pipe. And a plurality of copper nozzles penetrating through the cooling water channel are fixedly arranged between the outer-la