Extruders can be divided into single screw extruder, twin screw extruder and multi screw extruder according to the number of screws. Single screw extruder is suitable for extrusion of general materials. The laboratory twin screw extruder has the advantages of less heat generated by friction, uniform shearing of materials, large screw conveying capacity, stable extrusion volume, long stay of materials in the barrel and uniform mixing.
Single screw extruder plays an important role in both plasticizing and granulating machinery and molding machinery. In recent years, single screw extruder has made great development. The main symbol of the development of single screw extruder lies in the development of its key part-screw. In recent years, people have carried out a lot of theoretical and Experimental Research on the screw. Up to now, there are nearly 100 kinds of screws, including separation type, shear type, barrier type, shunt type and wavy type.
From the perspective of single screw extruder development, although it has been relatively perfect in recent years, with the continuous development of polymer materials and plastic products, new extruders with more characteristics will emerge.
The laboratory twin screw extruder has good feeding characteristics and is suitable for powder processing. It has better mixing, exhaust, reaction and self-cleaning functions than the single screw extruder. It is characterized by its advantages in processing plastics and blends with poor thermal stability. In recent years, domestic and foreign laboratory twin-screw extrusion experimental machines have been greatly developed. Various forms of laboratory twin screw extruder have been serialized and commercialized, and there are many manufacturers.
Advantages of laboratory twin screw extruder
1. Split barrel
In the past, the barrel of the laboratory twin screw extruder was integral and could not be opened. The split laboratory twin screw extruder is a split type, which is composed of upper and lower half barrel, the lower half barrel is fixed on the frame, and the upper half barrel is connected to the lower half barrel through a worm gear reducer. At ordinary times, the upper half of the barrel and the lower half of the barrel are fastened with two rows of bolts. When it is necessary to open the barrel, just loosen the bolts and turn the handle of the worm gear box to open the barrel.
2. Building block screw and barrel
The screw and barrel of the split laboratory twin screw extruder adopt advanced “building block” design. The screw is composed of various types of screw blocks fitted on the shafts. The inner bushing in the barrel can be adjusted according to the different screw blocks, so that the ideal screw element structure can be flexibly combined according to the material variety and other process requirements to realize the transportation, plasticization, refinement, shearing, exhaust, pressure building, extrusion and other processes. Thus, the contradiction between universality and specificity of the screw is solved. To achieve the purpose of multi-purpose and multi-function of one machine. Another advantage of the “building block” design is that the worn screw and barrel components can be replaced locally, avoiding the scrapping of the whole screw or barrel and greatly reducing the maintenance cost.
3. The twin screw of the twin screw extruder is of high-speed co direction meshing type, which can produce very strong and complex material transfer and exchange, shunt mixing and shear kneading in various threads and mixing elements. These functions can be fully and freely adjusted and controlled by changing the screw configuration and operating process conditions to meet the requirements of various processes.
4. Accurate measurement and reasonable feeding method are the key to strictly implementing the formula and the first pass to ensure the product quality. According to the performance of materials and the needs of users, we are equipped with a variety of feeding methods, such as volume measurement and loss-in-weight measurement, to meet the needs of different products.
5. Advanced control system. The extruder is equipped with an advanced and beautiful control system. Most of its control components are imported components, with good quality and high sensitivity. The operating parameters of the main engine, such as current, voltage, temperature and torque, are very intuitive, so it is very convenient to operate, and the requirements for operators are not high.
6. The system is equipped with water-cooling strand granulation, air-cooling die face hot granulation, underwater granulation and other granulation methods. It can be configured according to different materials and user requirements.
- Glass fiber reinforced, fuel resistant granulation (such as PA6, PA66, PET, PBT, PP, PC reinforced flame retardant, etc.)
- Granulation of high filler (e.g. PE, PP Filled with 75% CaCO3)
- Granulation of heat sensitive materials (such as PVC, XLPE cable materials)
- Color masterbatch
- Antistatic masterbatch, alloy, coloring, low filling, blending and granulation
- Granulation of cable material (such as sheath material and insulation material)
- XLPE pipe material granulation (such as master batch for hot water crosslinking)
- Mixing and extrusion of thermosetting plastics (such as phenolic resin, epoxy resin, powder coating)
- Hot melt adhesive, reactive extrusion granulation (such as EVA hot melt adhesive, polyurethane)
- K resin, SBS devolatilization granulation