PP and Calcium Powder Environmental Protection Sheet Extrusion Line

Composition of plastic extrusion machine
The main machine of a plastic extrusion machine is an extruder, which is composed of an extrusion system, a transmission system and a heating and cooling system.

Extrusion system
The extrusion system includes Extruder, Feeding system,Screen changer, Metering pump，T-die. The plastic is plasticized into a uniform melt through the extrusion system, and is continuously extruded by the screw under the pressure established in the process.
Screw and Barrel: It is the most important part of the extruder. It is directly related to the application range and productivity of the extruder. It is made of high strength and corrosion resistant alloy steel.The barrel cooperates with the screw to achieve the crushing, softening, melting, plasticizing, venting and compacting of the plastic, and continuously and uniformly conveys the rubber to the molding system. 
Feeding system: its function is to evenly transport different forms of plastics to the hopper of the extruder.
Screen changer: Its function is to remove all kinds of impurities in plastic
Metering pump: Equipping a pump in front of the extruder, checking pressure before the pump and controlling the speed of extrusion, which can minimizing pulsation and irregular material feeding and ensures the polymer is smoothly extruded and continuously delivered to the die head.  The shell of the pump adopts high-quality alloy-steel and 
the gear uses quenched chrome steel or other high-grade metallic materials which ensures high efficiency and leakage-proof.
T-die: The function of the T-die is to convert the plastic melt that rotates into parallel and linear movement, which is evenly and smoothly introduced.

Transmission system
The function of the drive system is to drive the screw and supply the torque and speed required by the screw in the extrusion process. It usually consists of a motor, a reducer and a bearing.

Heating and cooling device
Heating and cooling are necessary conditions for the plastic extrusion process to take place.
1. The extruder usually uses electric heating, which is divided into resistance heating and induction heating. The heating sheet is installed in the body, neck and head. The heating device heats the plastic in the cylinder externally to increase the temperature to reach the temperature required for the process operation.
2. The extruder cooling device is set to ensure that the plastic is in the temperature range required by the process. Specifically, it is to exclude the excess heat generated by the shear friction caused by screw rotation, so as to avoid the temperature being too high to make the plastic decompose, scorch, or shape difficult. The barrel cooling is divided into two types: water cooling and air cooling. Generally, small and medium-sized extruders are more suitable for air cooling, and large-sized ones are mostly water-cooled or combined with two forms of cooling.