Causes and solutions of extruder vacuum port leakage

During the extrusion process of the plastic recycling granulator, it is necessary to discharge the gas from the melt.If these gases are not discharged, defects such as pores and bubbles may appear on the surface or inside of the pellets,which will seriously affect the physical, mechanical, chemical and electrical properties of the final product. Set 1 to 2 exhaust ports between the feeding port and the machine head, which can remove the moisture and volatilization of other components in the molten extruded material.However, there are often some problems with the opening of the barrel, such as degassing port leakage.Few material will affect the discharge of water and also affect the final product quality,while a large amount of material will block the exhaust port and even cause shutdown.

There are generally two reasons for the leakage of material. One is that the design of the screw is unreasonable, which causes the material to flow out of the exhaust port.The second is that the design of the exhaust port is unreasonable, and the molten material is "hung" when it passes through the exhaust port.There are two solutions: 1: The screw adopts multi-stage design. The advantage of this design is that the exhaust port is at normal pressure, and the material will not flow out. 2: Change the size of the vent to meet the normal expansion of the melt at the vent. If the rolling material flow expands by 5-10mm, the depth of the exhaust port should be at least 5-10mm.