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What is the operation principle of blowing machine?
- Apr 13, 2018 -

Blow molding machine, after the liquid plastic is sprayed out, use the wind that the machine blows out, blow molding body to the mold cavity of a certain shape, make product, this kind of machine is called blow molding machine.The plastic is melted and quantified in the screw extruder, then it is formed by the mouth film, then the wind ring is cooled, and then the tractor is pulled at a certain speed, and the winding machine wraps it in a coil.

  • Working principle of blowing machine.

In the process of blown film production, film thickness uniformity is a key indicator of the vertical thickness uniformity can be controlled through extrusion and drawing speed stability, and the lateral thickness uniformity of film generally in accordance with the resistance in die precision manufacturing, and changes along with the production process parameters, in order to improve the lateral film thickness uniformity, to introduce automatic transverse thickness control system, the common control methods include automatic die thermal expansion screws (control) and automatic wind ring, it mainly introduces the principle and application of automatic wind ring.

  • Control scheme

The automatic wind ring is an on-line real-time control system, which is controlled by several motors distributed on the wind ring.By fan cooling airflow from the wind ring wind chamber after constant pressure distribution on each air duct, valve for opening and closing motion driven by a motor to adjust tuyere and the size of the air flow and change the die head discharging membrane billet cooling effect, so as to control the film thickness, from the control process, the membrane thickness change and the motor control quantity can not find a clear relationship between change and the thickness of different film thickness and the valve position control process nonlinear irregular change, between each adjustment are of great influence on adjacent point when a valve, and adjust the lag, and associated with each other, between the different time for this kind of highly nonlinear, strong coupling, time-varying uncertainty and control systems, and almost impossible to establish the precise mathematical model, even if is to establish mathematical model, it is also very complicated, difficult to solve, so that no practical value, and traditional control on the control model control effect is better, for the highly nonlinear, uncertain, complex feedback control effect is very poor and powerless.In view of this, we choose fuzzy control algorithm.At the same time, the change of fuzzy quantization factor is adopted to better adapt to the change of system parameters.

  • Blow molding machine blow molding process.

Blow moulding is also called hollow blow molding, a rapid development of plastic processing methods.Thermoplastic resin by extrusion or injection molding of plastic parison tube, hot (or heated to softening state), put in split cavity, mold closing immediately after ventilation with compressed air within the parison, make plastic parison swell and clingy wall in the mold, the cooling mold release, the products have all kinds of hollow.Blown film manufacturing technology on the principle and hollow blow molding is very similar, but it does not use the mould, from the perspective of classification of plastics processing technology, molding process is usually included in the extrusion of blown film.The blow molding process was used in the production of low density polyethylene bottles during world war ii.In the late 1950s, with the birth of high density polyethylene and the development of blow molding machine, blow molding technology was widely used.The volume of hollow containers can reach thousands of litres, and some of them have been computerized.It is suitable for blowing plastic with polyethylene, polyvinyl chloride, polypropylene, polyester, etc., and the empty container is widely used as an industrial packaging container.According to the method of moulding, blow molding can be divided into extrusion blow molding and injection blow molding, new development of multi-layer blowing and stretching blow molding.

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