Single-screw extruders consist of an Archimedean screw rotating in a heated barrel. Because of its simple structure, easy manufacture, high processing efficiency and low price, it is widely used.

At present, the single-screw extruder has developed from the basic helical structure at the beginning, such as damping screw block, exhaust screw, slotted screw barrel, pin barrel, building block structure and other different structure types. At the same time, due to The single-screw extruder occupies a small space and has become the main equipment used in the field of composite processing and plastic blown film.

Extrusion system

The main function of the extrusion system is to melt and plasticize the polymer material to form a uniform melt, and realize the transition from a glass state to a viscous flow state. And in this process, a certain pressure is established, and the screw is continuously extruded and conveyed to the die. Therefore, the extrusion system plays an important role in the molding quality and output of extrusion processing.

The extrusion system mainly includes parts such as feeding device, screw and barrel. It is the key part of the extruder. The screw is the heart of the extruder. Only through the rotation of the screw can the material move in the barrel, and the pressurization and partial pressure are obtained. heat.

Transmission system

The transmission system is usually composed of a motor, a reducer and a bearing, etc., and its main function is to drive the screw and supply the torque and torque required by the screw in the extrusion process. In the extrusion process, the screw speed is required to be stable and not change with the change of screw load to ensure uniform product quality. However, in different occasions, the screw is required to be able to achieve variable speed, so as to achieve the requirement that one equipment can adapt to the extrusion of products of different materials or different shapes. In most extruders, the change of screw speed is achieved by adjusting the motor speed, and the transmission system is also equipped with a good lubrication system and a rapid braking device.

Heating and Cooling Systems

The heating and cooling system of the extruder consists of a heating device and a cooling device, which is a necessary condition for the extrusion process to proceed smoothly. Require.

The cooling device is generally arranged in the extruder barrel, screw and the bottom of the hopper and other parts. Barrel cooling can be water-cooled or air-cooled. Generally, small and medium-sized extruders mostly use air-cooling; large-scale extruders mostly use water-cooling or a combination of the two. The screw cooling mainly adopts central water cooling, the purpose is to increase the solid conveying rate of the material, stabilize the output, and at the same time improve the product quality. The cooling device at the bottom of the hopper is mainly to strengthen the conveying effect of solid materials, to prevent the material particles from sticking due to temperature rise, blocking the material opening and affecting the feeding. Generally, for extruders and high-speed extruders with a screw diameter of more than 90mm, a cooling device must be installed at the bottom of the hopper.