Extruder barrel heating is widely used resistance heating, and thermocouples are used to achieve segmented temperature control and side detection. Resistance heating is the use of resistance to generate heat to heat the extruder barrel, and then transfer the heat to the plastic in the extruder barrel. Resistance heating mainly includes strip heaters, cast aluminum heaters, ceramic heaters, etc. These heaters have the advantages of small size, easy manufacture and maintenance.
According to the different plasticizing states of the material along the screw axis of the extruder, in order to make the degree of distribution of the extruder barrel meet the requirements of the injection molding process, the heating of the screw machine must be carried out in stages to improve the plasticizing capacity. Generally, (3-5) Ds, (Ds is the diameter of the rod) is a heating temperature control section, and the heating temperature control fluctuation range should generally not exceed 5 °C, and should preferably not exceed 2 °C for heat-sensitive plastics.
When determining the heating power of the extruder barrel, in addition to the heat required for plasticization, it is also necessary to meet the requirements of the productivity of the injection molding machine to ensure that the extruder barrel has a sufficiently fast heating rate. The heating time of machine heating is not more than 30min for small machines, and is generally about 1h for large and medium-sized machines.
1. Under normal circumstances, the extruder barrel does not need to be equipped with a cooling control system, and the process requirements can be met by natural cooling. However, if the temperature of the feeding port is too high, the phenomenon of "bridging" will appear at the feeding port, making feeding difficult or even impossible.
2. In order to ensure good feeding and conveying conditions of solid materials and prevent the heat of the extruder barrel from being transferred to the transmission parts, a cooling jacket (slot) should be set at the feeding port of the extruder barrel, and according to the The process requires that the amount of cooling water can be adjusted. In addition, when heat-sensitive plastics are processed at higher speeds, the extruder barrel must be cooled and temperature-controlled to prevent thermal decomposition of heat-sensitive plastics.
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As a professional extruder spare parts manufacturer in China, LESUN provides screws element and screw barrels. The extruder screw types include conveying screw element, kneading screw element, mixing screw element, etc; Screw barrels include extruder closed screw barrel, extruder closed screw barrel, extruder feed barrel, extruder side-feed barrels, etc. Custom service is available. Meanwhile, we also provide surveying and mapping business as well as processing business for accessories made by major extruding machine companies. Feel free to contact us.