The basic working principle of the extruder screw and barrel is to melt and compact the polymer, push it to the mold at constant pressure, constant temperature and constant speed, and form a parison in the molten state of the product through the mold. However, the structure of the single-screw extruder and the twin-screw extruder are different, the working principle is different, and the control process conditions are also different.

Ⅰ. Structural characteristics of extruder screw and barrel

The single-screw extruder is composed of a transmission system, an extrusion system, a heating and cooling system, a control system, etc. (there are also some auxiliary equipment). The extrusion system is the key part of extrusion molding, which plays an important role in the molding quality and output of extrusion. The extrusion system mainly includes several parts such as feeding device, barrel, extruder screw elements, die and die.

Extrusion molding process is suitable for all polymer materials. It can mold almost all thermoplastics and can also be used for thermosetting plastics, but only a few thermosetting plastics such as phenolic. Plastic extrusion products include pipes, plates, bars, sheets, films, monofilaments, cable cladding, various profiles, and composites of plastics and other materials.

Currently about 50% of thermoplastic products are formed by extrusion. In addition, the extrusion process is also commonly used in the coloring, mixing, plasticizing, granulating and blending modification of plastics, etc. Based on extrusion molding, combined with technologies such as inflation and stretching, it has been developed into extrusion Blow molding and extrusion tenter molding manufacture products such as hollow blow molding and biaxially stretched films. It can be seen that extrusion molding is the most important method in polymer molding.

Ⅱ. The classification of extruder screw barrel

There are two types of screw extruders and plunger extruders. The former is continuous extrusion and the latter is intermittent extrusion. It is mainly used for high-viscosity material molding, such as polytetrafluoroethylene, ultra-high molecular weight polymer. vinyl.

Screw extruders can be divided into single screw extruders and multi-screw extruders. The single screw extruder is the most basic extruder in production. Among multi-screw extruders, twin-screw extruders have developed the fastest in recent years, and their applications have become increasingly widespread.

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. But in the extrusion processing of other polymers, single-screw extruders still dominate.

Ⅲ. Characteristics of extruder screw and barrel

1. Simple structure and low price.

2. It is suitable for plasticizing extrusion of polymers and extrusion processing of pellets. There is little shear degradation to the polymer, but the material stays in the extruder for a long time.

3. Easy to operate and simple process control.

LESUN is a leading extruder spare parts manufacturer in China, providing 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.