High quality polyethylene profile extrusion foaming equipment
DATE：2022/1/13 8:48:52 / READ： / SOURCE：This station
High quality polyethylene profile extrusion foaming equipment
①Equipment parameters. A new type of single-screw screw for extrusion foaming of high-quality polyethylene profiles, with an aspect ratio of 2 to 30 and a compression ratio of (211) (31). The length of the screw metering section is determined by the full length of the screw and the resistance surface of the die. Under normal circumstances, the length of the metering section is inversely proportional to the matching of the die force, and the length of the metering section is required not to exceed 10 diameters per month.② Screw diameter. To determine the diameter of the screw is to choose the size of the extrusion host. It is recommended to choose according to the size of the cross-sectional area of the profiled material, the output and the pulling speed. For example, for a single-screw extruder with a diameter of 65mm, the cross-sectional area of the profiled material is 2-6cm2, and the traction speed is between 6-12m/min, and the output is about 45-80kg/h. If there is a forced feeding system, the output can be Up to 100kg/h or more. For the twin-screw extruder, the size of the main machine is selected according to the output of 65-86kg/h for the profiles of the same surface. The specific selection should also consider the influence of factors such as pulling speed, foaming ratio, cooling speed and so on.
②High resistance nose. For the high resistance die, the screw length is 20D, and the compression ratio is 3:1. The best results are obtained. For the low resistance die, the mixing capacity of the screw itself is higher. The length of the rod used is (25~30)D, and the compression ratio It is 1.5 to 1.8, so that good quality foamed products can also be obtained.
In addition to normal heating, the heating machine should preferably have an air cooling device. The screw can be internally circulated with heat for proper temperature adjustment. screw head. The shape of the head of the rod should not be in the form of a dead center at the top. The flow cross-sectional area of the front end of the machine should not be too large, and the pressure should be released in advance to foam. In the same way, it is necessary to avoid excessive agitation caused by the mixing elements on the screw, and there should be no sudden flow direction changes. The mold sleeve is used for shaping. According to the traction speed of most profiles, the mold sleeve shaping device can be set at a distance of about 25 to 300 mm from the exit of the die lip. Then use a cooling vacuum water tank or a vacuum water tank to cool and shape.
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