Hotline:+86 0769-86386302
4News Center

What is the knowledge of plastic product processing?

  1. Injection molding of plastic products
   Injection Molding refers to the method in which heated ablation data is injected into the cavity by high pressure and solidified by cooling to obtain a molded product. This method is suitable for mass production of disorganized parts and is one of the important processing methods.
   The injection molding process can be roughly divided into the following six periods:
   1. Clamping
   2, injection
   3, hold pressure
   4, cooling
   5, open the mold
   6, the finished product is taken out
   When the above technique is repeated, the finished product can be continuously produced.
   2. Injection molding machine
   Injection molding machines can be divided into clamping equipment and injection equipment.
   The primary effect of the clamping device is to complete the opening and closing of the plastic product and to eject the finished product. The clamping device can be divided into a link type as shown in the figure and a direct pressure type in which the clamping is directly applied by hydraulic pressure.
   The injection equipment is a device that causes the resin data to be ablated by heat and then injected into the processing of the plastic product. The resin is extruded from the head into the barrel as shown, and the melt is conveyed to the front end of the barrel by rolling of the screw.
   In that process, heating under the effect of the heater heats the resin material in the barrel, and the resin is melted under the shear stress effect of the screw, which will be equivalent to the molded product and the dry channel, the molten resin of the runner. Staying at the front end of the barrel (called metering), the screw continuously feeds the data into the mold cavity.
   When the molten resin is active in the processing of the plastic product, the moving speed (ejection speed) of the screw must be manipulated, and the pressure (pressure maintaining) is manipulated after the resin is filled in the cavity.
   When the screw orientation and the injection pressure reach a certain value, we can switch the speed control to pressure control.
   The so-called plastic product processing (Mold) refers to a device in which a resin material is injected into a metal mold to obtain a finished product having a certain shape.
   Although it is not indicated in the figure, in fact, in order to control the temperature of the processing of plastic products, there are cooling holes, heaters and the like for passing the refrigerant (warm water or oil) in the processing of the plastic products.
   The material that has become melt enters the dry channel, and through the split runner, the gate is injected into the cavity. After the plastic product is turned over after the cooling period, the ejector device on the molding machine will eject the ejector rod and push the finished product out.
   4, molded products
   The molded article is composed of a dry flow path through which the molten resin flows, a split runner that guides the molten resin into the cavity, and a finished product.
   If only one product can be obtained in one molding, the production power is not high. If we use a shunt to connect multiple cavities together, we can form several products together.
   At this moment, if the length of the shunt to each cavity is not flat, the resin cannot be injected into the cavity at the same time, resulting in a difference in the scale, appearance, and physical properties of each finished product. Therefore, we usually design the length of the runner to be flat.
   5, the use of return materials
   The dry runners and runners in the molded article are not commodities, and sometimes they are thrown away or destroyed and reused as molding materials. Let's call it a return.
   The return material is usually not used as a molding material alone, and is usually used after mixing with new materials. This is because after a single molding, the resin's plastic product processing functions, activity, color and other characteristics will change.
   The mixed proportion of new material and return material is usually controlled below 30%. If the use of recycled material is too high, it may reduce the inherent characteristics of the data. Even if the amount of recycled material is controlled below 30%, it is necessary to To determine the quality requirements of the finished product, the strength, the processing structure of the molded plastic product, the shape of the molded product, etc., to determine the accurate use of the return material.
   In particular, fill level information, pay special attention to this.