As we all know, extrusion molding process is a molding processing method in the field of polymer processing, which has many varieties, many changes, high productivity, strong adaptability, wide application and a large proportion of output. Extrusion molding means that the polymer melt (or viscous fluid) is molded through a certain shape of die under the extrusion action of Yantai extruder screw, and the product is a continuous profile with a constant cross-sectional shape.

                                                                                                                                        Yantai extruder equipment

The extrusion process is suitable for all polymer materials. It can be used for molding almost all thermoplastics and thermosetting plastics, but it is only limited to a few thermosetting plastics such as phenolic aldehyde. Plastic extruded products include pipes, plates, bars, sheets, films, monofilament, cable cladding, various profiles and composites of plastics and other materials. At present, about 50% of thermoplastic products are formed by extrusion. In addition, extrusion technology is also often used for coloring, mixing, plasticizing, granulation and blending modification of plastics. Based on extrusion molding, combined with inflation, stretching and other technologies, it has developed into extrusion-blow molding and extrusion tentering molding to manufacture hollow blow molding and biaxially stretched films. It can be seen that extrusion molding is an important method in polymer molding.

There are two kinds of extrusion equipment: screw extruder and plunger extruder. The former is continuous extrusion, while the latter is intermittent extrusion, which is mainly used for forming high viscosity materials such as PTFE and high molecular weight polyethylene. Screw extruder can be divided into single screw extruder and multi-screw extruder. Single screw extruder is the basic extruder in production. Twin-screw extruder among multi-screw extruders has developed rapidly in recent years, and its application is increasingly extensive. At present, in the processing of PVC plastic door and window profiles, the twin-screw extruder has become the main production equipment, and the single-screw extruder will be phased out. However, in the extrusion processing of other polymers in Yantai extruder, the single screw extruder still dominates.