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NCK Technology Co.,Ltd

Plastic Injection Molding Production Efficiency Is High

Plastic injection molding process: high-speed high-pressure will lead to melt in the gate position to produce excessive shear force, while the melt and the cavity wall shear and melt core layer and the cortex between the shear will be a sharp increase; , Injection temperature / mold temperature is too low, reducing the melt flow, fill the process of increasing the flow resistance, resulting in high shear force. Therefore, Custom Injection Molding And Plastic Molding to reduce the injection speed, injection pressure, injection temperature / mold temperature can effectively reduce the shear force, reduce or eliminate the occurrence of skin. Try to avoid the high shear force during the filling process is the best entry point to improve the phenomenon of injection molding.

Plastic injection molding is a method of forming a thermoplastic or thermosetting molding material in a mold cavity by uniformly plasticizing it in a heating cylinder and then by a plunger or a moving screw to a closed mold. Injection molding is suitable for almost all thermoplastics. Custom Injection Molding And Plastic Molding In recent years, injection molding has also been successfully used to shape certain thermosetting plastics. Injection molding of the molding cycle is short (a few seconds to a few minutes), the quality of molded products from a few grams to dozens of kilograms, can shape a complex shape, accurate size, with metal or non-metallic insert molding. Therefore, the method of adaptability, high production efficiency. Injection molding machine is divided into plunger injection molding machine and screw injection machine two categories, by the injection system, clamping system and mold three parts;

Thermoplastics and thermosetting plastics will reduce viscosity when heated. However, the viscosity of the thermosetting plastic increases with time and temperature due to the chemical cross-linking reaction. The combined result of these effects is that the viscosity is U-shaped with time and temperature. Custom Injection Molding And Plastic Molding This is the purpose of thermosetting injection molding in the lowest viscosity area, since the pressure required for the material to form the mold is the lowest. This also helps to minimize damage to the fibers in the polymer.

Custom Injection Molding And Plastic Molding The injection molding process uses a screw to flow the material through the heated barrel, and the barrel is circulating in water or oil around the jacket in the barrel. The screws can be designed in different types of each material, compressed slightly to remove air and heat the material to obtain low viscosity. The flow of most thermosetting materials here is quite good.

So that the operation of the material into the mold is to stop the screw rotation and hydraulic pressure to push the screw high speed, so that the plasticized low viscosity material into the mold. Custom Injection Molding And Plastic Molding This rapid flow requires 0.5 seconds to fill the cavity, the pressure to reach 193MPa. The high-speed flow of the material, once filled with the membrane chamber, produces greater frictional heat to accelerate the chemical reaction. Once the cavity is filled, the injection pressure will drop to the packing pressure of 34.5-68.9MPa. This pressure is maintained on the material for 5-10 seconds, then depressurizes, and then begins the next cycle of plasticization.

This material is held in a hot mold until it hardens, then open the mold clamping device and eject the product. The product may be simply uncured and slightly softened, and the final cure will be done within 1 minute or 2 minutes after removal using the heat retained inside the product. Custom Injection Molding And Plastic Molding The entire production cycle of the thermosetting product is 10-120 seconds, depending on the thickness of the product and the type of raw material.

Many different and specialized techniques have been used to improve the quality and reproducibility of the product. In view of the fact that some thermosetting polymers produce gas upon heating, Custom Injection Molding And Plastic Molding there is often a bleed operation after the mold is partially filled. In this step, the mold opens slightly so that the gas escapes and then closes quickly and refills the remaining material.

Plastic injection molding provides high strength, better dimensional control, and improved surface state (appearance), which is due to the use of a telescopic film cavity and the core of the mold obtained, the injection process can be Open 1/8-l / 2 in, and then quickly press, like the mold off.

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