HC plastic mesh News: Injection molding is an engineering technology, it is related to the content Plastic Into useful and can maintain the original performance of the products. The importance of injection molding processing conditions affect the plastics flow and cooling the temperature, pressure and the corresponding time for each role.
1, temperature control 1, Barrel Temperature: injection molding process requires temperature control of barrel temperature, nozzle temperature and Mold Temperature. Temperature mainly affects the first two-way Plastic The plastics and mobile, the latter mainly affects the temperature of plastic flow and cooling. Each has a different plastic flow temperature, the same plastic as the source or brand is different, the flow temperature and decomposition temperature is a difference, this is due to different molecular weight and molecular weight distribution caused by different types of injection plastic machine plasticizing process is different, so select the barrel temperature is not the same.
2, nozzle temperature: nozzle temperature is usually slightly lower than the highest temperature of the barrel, This is to prevent melt through nozzles that may occur in the “drooling phenomenon.” Nozzle temperature can not be too low, otherwise it will result in the early melt coagulation and the nozzle closed, or because of material into the mold cavity as early condensate affect product performance.
3, mold temperature: mold temperature on the product’s inherent quality of performance and apparent great effect. Mold temperature is decided by the availability of the plastic crystal, the size and structure of products, performance requirements, and Other Processing conditions (melt temperature, injection speed and injection pressure, molding cycle, etc.).
Second, pressure control: Pressure injection molding process, including two kinds of plastics pressure and injection pressure, and directly affects the quality of plastic, plastics and products.
1, plasticizing pressure: (back pressure) using Screw Type injection machines, screw the top back turning the screw melt when the pressure on the pressure as plastics, also known as backpressure. The size of such pressure is the pressure relief valve by the hydraulic system to adjust. The injection, the plasticization pressure, the size of screw speed with all the same, an increase of pressure that will increase the plastics melt temperature, but will reduce the speed of plastics. In addition, the increased pressure often make plastics melt temperature uniformity, pigment and mixed evenly melt the gas discharge. Normal operation, the plasticization pressure, the decision should be to ensure good quality products under the premise of the lower the better, its specific value is used in plastics with different varieties, but seldom more than 20 kg / cm 2 .
2, injection pressure: in the current production, almost all of the injection machine injection pressure is to screw the top on the plastic plunger or by the pressure (the pressure from the oil line conversion to a) the yardstick. Injection pressure in injection molding the role is to overcome the flow of plastic from the barrel cavity flow resistance, filling to melt and the melt rate for compaction.
3, molding cycle Complete a course of time required for injection molding, said molding cycle, also known as the molding cycle. It actually includes the following components:
Molding cycle: cycle time directly affects the labor and equipment utilization rates among students, so the production process, should be the premise of guaranteeing quality, shorten the molding cycle, all the time. Throughout the molding cycle time for injection and cooling time is most important, the quality of their products have a decisive impact. Injection time of the filling time is directly inversely proportional to the filling rate, filling time is usually the production of about 3-5 seconds.
Injection time of the holding pressure time is plastic on the cavity pressure time, the injection time in the proportion of large, generally about 20 to-120 seconds (thick workpieces up to 5 to 10 minutes). Frozen at the gate to melt before the holding time of how much impact on the accuracy of product size, if in the future, was not affected. Holding time is also the most favorable value, known it depends on the melt temperature, mold temperature and the main channel and the gate size. SABUNG AYAM