The main engine of China plastic extruder is extruder, which consists of extrusion system, transmission system and heating and cooling system. China JWELL as extruder manufacturer, pp hollow sheet extrusion line is also a kind of plastic machinery. According to the angle between the material flow direction of the head and the center line of the screw, the extruder divides the head into a bevel head and a right-angle head. The shell of the machine head is fixed on the fuselage with bolts. The mold in the machine head has a mold core seat and is fixed on the inlet port of the machine head with a nut. The front of the mold core seat is equipped with a mold core, a mold core and a mold core seat. There is a hole in the center for passing the core wire.
Principle of pp hollow sheet extrusion line
China pp hollow sheet extrusion line single screw is generally divided into three sections in effective length, and the effective length of the three sections is determined according to the diameter of the screw, the pitch and the depth of the screw, generally divided into one third each.
The last thread of the material port begins to be called the conveying section: the material is required not to be plasticized here, but it must be preheated and pressed to be firm. Solid plug, that is to say, the material here is a solid like a plug after being squeezed, so as long as the conveying task is completed, it is its function.
The second section is called the compression section. At this time, the volume of the screw groove gradually becomes smaller, and the temperature must reach the degree of plasticization of the material. The compression is generated here from the third section of the conveying section, and it is compressed to one here. This is called the compression ratio of the screw– 3:1, some machines also have changes, and the plasticized material enters the third stage.
The third section is the metering section, where the material maintains the plasticizing temperature, just like a metering pump to accurately and quantitatively transport the melt material to supply the machine head. At this time, the temperature cannot be lower than the plasticizing temperature, generally slightly higher.
The control system of China JWELL as extruder manufacturer’s plastic extruder includes heating system, cooling system and process parameter measurement system, mainly composed of electrical appliances, instruments and actuators (ie control panel and operating table). Its main function is to control and adjust the driving motor of the main and auxiliary machines, output the speed and power that meet the technological requirements, and make the main and auxiliary machines work in harmony.
Control principle of pp hollow sheet extrusion line
The electrical control of pp hollow sheet extrusion line is roughly divided into two parts: transmission control and temperature control, which realizes the control of the extrusion process including temperature, pressure, screw revolution, screw cooling, barrel cooling, product cooling and outer diameter control, and Pulling speed, neatly arranging the wire and ensuring constant tension take-up control on the take-up reel from empty to full.
1.Temperature control of the extruder host
The plastic extrusion of wire and cable insulation and sheathing is carried out in a viscous flow state according to the deformation properties of thermoplastics. In addition to requiring external heating of the screw and barrel, which is transmitted to the plastic to melt and extrude, the heat generated by the screw itself when extruding the plastic is also required. Therefore, the temperature of the host should be considered as a whole, including the opening and closing of the heater. It is necessary to consider the factor of the extrusion heat overflow of the screw to cool it, and there must be effective cooling facilities.
2.Pressure control of extruder
In order to reflect the extrusion situation of the PP/PE Plastic Hollow Cross Section Plate Extrusion Line head, it is necessary to detect the head pressure during extrusion. Since the domestic extruder does not have a head pressure sensor, the measurement of the thrust after the screw extrusion is generally used instead of the head pressure. Measurement, the screw load table can correctly reflect the size of the extrusion pressure. The fluctuation of extrusion pressure is also one of the important factors that cause unstable extrusion quality. The fluctuation of extrusion pressure is closely related to factors such as extrusion temperature, the use of cooling device, and the length of continuous operation time.
3.Control of screw speed
The adjustment and stability of the screw speed is one of the important technological requirements of the host drive. The screw speed directly determines the amount of glue and the extrusion speed. In normal production, it is always desirable to achieve the highest speed and high output as much as possible. When the screw speed of the extruder is required to be from the start to the required working speed, the available speed regulation range should be large. .
4.Tension control required for winding
In order to ensure the wire take-up at different line speeds and the constant tension requirement from empty reel to full reel, it is hoped that the wire take-up and reel device has a tension adjustment mechanism for storing the wire, or the rewinding of the constant line speed system and the constant tension system is considered electrically. and many more.
5.Electrical automation control of the whole machine
This is the process control requirement to realize the high-speed extrusion production line. China JWELL as extruder manufacturer mainly includes: start-up temperature interlock; working pressure protection and interlock; proportional synchronous control of the transmission of the two major components of extrusion and traction; Synchronous control of traction; online detection and feedback control of outer diameter; control of single machine and complete machine tracking of components according to various needs.
pp hollow sheet extrusion line operating procedures
China JWELL as extruder manufacturer, each type of product in the plastic extrusion production line has its own operating characteristics. Only with a detailed understanding of its operating characteristics can the machine’s efficiency be fully utilized. pp hollow sheet extrusion line is one of the types and it is necessary to grasp the operating points of the extruder and use the extruder correctly and reasonably. The use of screw extruder includes a series of links such as installation, adjustment, commissioning, operation, maintenance and repair of the machine. However, the working system of the screw extruder is the extrusion system, but it has unique characteristics, and special attention should be paid to its characteristics when using the screw extruder.
The installation, adjustment and commissioning of the machine are generally clearly stipulated in the extruder’s operating instructions. Here, the operation points, maintenance and maintenance of the extruder are briefly described as follows:
China JWELL as extruder manufacturer reminds operators that they must be familiar with the structural characteristics of the pp hollow sheet extrusion line they operate, especially the structural characteristics of the screw, the characteristics of the heating and cooling control instruments, the characteristics of the machine head and the assembly conditions, etc. Master the extrusion process conditions and operate the machine correctly.