The operation mode of Dalian extrusion molding has made continuous progress from manual to mechanical to hydraulic. However, no matter which form in this period, it only reflects the difference of operation difficulty and manual labor intensity, and the essence of the production process: intermittent is the common feature of the extruder in that period. Extruding rubber is not a problem, but for thermoplastics, it is impossible to meet the plasticization requirements.
In addition to increasing the length diameter ratio of the extruder screw, many improvements have been made in heating mode, feeding device and transmission device; In 1939, they developed the plastic extruder to a new stage. Only through molding can polymers become valuable products. Molding is an indispensable production link of polymer materials. Modified polymer materials were prepared by extrusion.
Blending strengthening and toughening technology, radiation modification technology, nanocomposite technology and other new modification technologies; Extruders and production lines with various structures and functions; Mixing screw, exhaust extruder, twin screw, multi screw extruder, reaction extruder, combined extruder, forming device established to adapt to the physical and chemical properties of polymer materials.
However, in the application of these technologies, we can still innovate, develop new products, manufacture new materials and form new technologies. Compared with other polymer forming methods, extrusion has many outstanding advantages. It can also be used for continuous mixing, plastic refining and granulation of rubber filter and raw rubber. In the process of producing resin in petrochemical plant, the water in resin can be removed by extrusion with extruder.
The mixing of additives and modifiers in various brands of resin is completed by extruder to complete the resin granulation process. The production of plastic products completely used or containing extrusion process in the process accounts for about half of the total amount of thermoplastic products. The products formed by this method are used in agriculture, construction industry, petrochemical industry, machinery manufacturing, medical devices, automobile, electronics, aerospace and other industrial sectors.
