Vertical injection molding machine temperature and pressure control

Date：2014/7/1 14:53:06

         Vertical injection molding machine is an engineering and technology, it relates to the contents of the plastic into useful and can maintain the original performance of the products. Important vertical injection molding process conditions affect the plastics injection molding machine and cooling the flow temperature, pressure and time corresponding to the respective action.
A vertical injection molding machine temperature control
         1, barrel temperature: injection molding injection molding process requires vertical injection molding machine barrel temperature control temperature, nozzle temperature and mold temperature. The first two principal effects plasticization temperature and flow, the latter mainly affects the temperature of the plastic flow and cooling. Each has a different plastic flow temperature, with a plastic, due to different sources or grades, the current temperature and the decomposition temperature there is a difference, as the average molecular weight and molecular weight distribution due to different types of plastic stand in different plasticizing process within the injection molding machine is different, so select the barrel temperature is not the same.
         2, the nozzle temperature: nozzle temperature is generally slightly lower than the maximum temperature of a cylinder, which is to prevent the melt in the nozzle may occur through "drooling phenomenon." Nozzle temperature can not be too low, otherwise it will cause early melt and pour nozzle blocked, or because of early condensate material into the mold cavity and affect the performance of products
         3, mold temperature: mold temperature great impact on the intrinsic properties of the products and the apparent quality. Mold temperature is decided by the presence or absence of crystallinity of the plastic, the size and structure of the product, performance requirements, and other process conditions (melt temperature, injection speed and injection pressure, the molding cycle, etc.).
Second, vertical injection molding machine pressure control: pressure injection molding process includes two pressure plasticizing and injection pressure, and directly affects the quality of plasticizers and plastic products.
         1, vertical injection molding machine plasticizing pressure: when (backpressure) using screw injection machine, the top of the screw in the screw rotates melt pressure exerted retreat called plasticizing pressure, also known as back pressure. The magnitude of this pressure is through the pressure relief valve in the hydraulic system to be adjusted. In the vertical injection molding machine, the size of the plasticization pressure i.e. when the temperature of the melt increases with the rotational speed of the screw is constant, the increased plasticizing pressure, but reduced plasticizing speed. In addition, increased pressure often make the plasticizing temperature of the melt evenly and uniformly mixing the toner discharge gas in the melt. General operation, the pressure should be decided plasticized guarantee excellent product quality premise as low as possible, the specific values ​​are used in plastics with different varieties, but usually little more than 20 kg / sq cm.
         2, vertical injection molding machine injection pressure: In the current production, the injection pressure is almost all vertical injection molding machine are based on the plastic screw top plunger or the applied pressure (translated by the line pressure to come) prevail in . In the vertical injection molding machine injection pressure in the role, the plastic from the barrel to overcome the flow resistance of the flow of the cavity, given the rate of the melt and filling the melt on compaction.

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