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Operating Principle
- Jan 04, 2018 -

A brief overview

In the blown film production process, the film thickness uniformity is a key indicator of which the vertical thickness uniformity can be controlled by the extrusion and traction speed stability, and the horizontal thickness of the film is generally based on the resistance to die precision manufacturing , And with the change of production process parameters, in order to improve the film thickness uniformity, the need to introduce automatic horizontal thickness control system, the common control methods are automatic die and automatic air ring, mainly introduces the principle and application of automatic air ring.


The structure of the automatic wind ring adopts double tuyere mode, in which the air volume of the lower tuyere is kept constant, and the upper tuyere circle is divided into several wind channels on the circumference. Each wind channel is composed of air chamber, valve, motor and the like, Degree, control the size of each duct air volume. In the control process, the film thickness signal is detected by the thickness probe and transmitted to the computer. The computer compares the thickness signal with the current average thickness. The thickness deviation and the trend of the curve are used to control the movement of the valve. On the contrary, the motor moves in the reverse direction and the tuyere increases. By changing the air volume at each point on the circumference of the air ring, the cooling rate at each point is adjusted so that the lateral thickness deviation of the film is controlled within the target range .