A blow molding machine is a plastic processing machine. After the liquid plastic is sprayed out, the plastic body is blown and attached to a mold cavity of a certain shape by using the wind blown out by the machine to make a product. This kind of machine is called a blow molding machine. The plastic is melted and extruded quantitatively in the screw extruder, and then shaped through the mouth film, and then cooled by the wind ring, and then pulled by a tractor at a certain speed, and wound into a roll by a winding machine.
In the process of blown film production, the uniformity of film thickness is a key indicator, in which the uniformity of longitudinal thickness can be controlled by the stability of extrusion and traction speed, while the uniformity of film transverse thickness generally depends on the precision manufacturing of die head , and changes with the change of production process parameters. In order to improve the uniformity of film transverse thickness, an automatic transverse thickness control system must be introduced. Common control methods include automatic die head (thermal expansion screw control) and automatic air ring. Here we mainly introduce the automatic air ring. Principles and Applications.
The structure of the automatic air ring adopts the double air outlet method, in which the air volume of the lower air outlet remains constant, and the upper air outlet is divided into several air ducts on the circumference. Each air duct is composed of an air chamber, valves, motors, etc., and the motor drives the valve to adjust the air duct opening to control the air volume of each air duct.
3.Control plan
The automatic air ring is an online real-time control system, and the controlled objects of the system are several motors distributed on the air ring. The cooling air sent by the fan is distributed to each air channel after passing through the air ring air chamber at constant pressure, and the motor drives the valve to make opening and closing movements to adjust the size of the air port and air volume, and change the cooling effect of the film blank at the outlet of the die head. In order to control the thickness of the film, from the perspective of the control process, there is no clear relationship between the film thickness change and the motor control value. The range between the thickness change of different thickness films and different valve positions and the control value is nonlinear and irregular. Every time a valve is adjusted The time has a great influence on the adjacent points, and the adjustment has a hysteresis, so that different times are correlated with each other. For this highly nonlinear, strong coupling, time-varying and control uncertainty system, its precise mathematical model is almost impossible. Even if the mathematical model can be established, it is very complicated and difficult to solve, so that it has no practical value, while the traditional control is better for the control of the deterministic control model, but the control effect is poor for the highly nonlinear, uncertain, and complex feedback information. Couldn't even do anything about it. In view of this we have chosen the fuzzy control algorithm. At the same time, the method of changing the fuzzy quantization factor is adopted to better adapt to the change of system parameters.
1. The central shaft of the screw and the cylinder are made of 38CrMoAlA chromium, molybdenum and aluminum alloy treated with nitrogen, which has the advantages of high thickness, corrosion resistance and wear resistance.
2. The die head is chrome-plated, and the screw mandrel structure makes the discharge more even and smooth, and the blown film can be better completed. The complex blown film machine structure makes the output gas more uniform. The lifting unit adopts a square frame platform structure, and the height of the lifting frame can be automatically adjusted according to different technical requirements.
3. The unloading equipment adopts peeling rotating equipment and central rotating equipment, and uses torque motor to adjust the smoothness of the film, which is easy to operate.
MEPER is a leading blow molding machine manufacturer in China, we focus on R&D, manufacturing and sales of 100l blow molding machines. The company has a group of technical backbones and excellent service teams with more than 20 years of experience in the industry, and has passed the ISO9001:2008 quality management system and CE, SGS certification. Based on good reputation and excellent service, the products are exported to more than 40 countries overseas, with an annual output of more than 400 units, which has been highly praised and trusted by overseas customers.
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