The PE pipe extrusion production line is composed of feeding system, single screw extruder, special die for PE pipe, sizing, cooling system, tractor, voucher collector and control system. The characteristics of PE pipe extrusion production line are as follows:
(1). The plastic pipe extrusion machine used in pipe processing are single screw extruders. In the design of single screw extruder, how to realize high-speed extrusion of high-quality pipe at low processing temperature is a key technology.
(2). In the screw design, the combination of BM structure and barrier structure is adopted, and a special mixing section is added, which not only ensures the plasticization effect of pipe blank, but also the melt pressure is low and the pressure distribution is uniform in all areas of the whole screw. At the same time, the shear action is strictly controlled to obtain the ideal material temperature.
(3). In the cylinder design, the extrusion production line adopts slotted cylinder, specially designs feeding bushing with structure, and multiple inclined grooves on the inner hole surface ensure PE high-speed feeding.
A special cooling device is designed in the feeding section to control the temperature of the cylinder feeding area and isolate it from the adjacent cylinder high temperature area.
(4). Each section of the linder has a heating section with controllable temperature, which adopts forced air cooling, and the output of the extrusion production line has a good linear relationship (easy to be adjusted synchronously with the traction speed). For example, in order to realize high-speed extrusion, the pp pipe extrusion machinecy reduction gearbox with high torque and low noise is adopted, and the motor power is matched accordingly.
(1). Cooling device: the function of the setting die is to ensure that the high-temperature parison extruded from the die obtains a fixed geometry and size in the vitrification process, and basically eliminate the deformation internal stress and thermal internal stress of the parison in the process, so as to obtain products meeting relevant quality standards. It is the main process device in the plastic extrusion process.
(2). Traction device: the traction device is a necessary auxiliary device for the continuous extrusion of plastic pipes in the extrusion production line. Its function is to provide a certain traction force and traction speed for the PE that has been preliminarily finalized from the machine head, overcome the friction generated in the cooling and finalization process, and make the plastic pipes lead out from the cooling and finalization device at an even speed.
The wall thickness of PE pipe is adjusted by adjusting the traction speed to obtain the standard pipe especially in the hdpe pipe extruder. Practice has proved that the tensile strength of plastic pipes produced without traction is obviously lower than that with traction, and the output can be increased when equipped with traction device.
(3). Requirements for traction device: the gripper shall be able to meet the needs of supporting the processing of multiple caliber tubes. The extrusion production line can adjust speed steplessly and smoothly within a certain range. In the traction process, the traction speed must be stable.
Because any irregular change will form ripples on the product surface and affect the product quality, the traction and clamping force shall be moderate and adjustable, and there shall be no slip, runout and vibration in the traction process to avoid permanent deformation of the pipe.