Plastic injection molding is widely used in the production of various plastic products. Mastering the correct usage techniques helps improve product quality, production efficiency, and reduce costs. Energy-saving solutions must be matched with the production cycle time to avoid sacrificing efficiency for excessive energy saving.
Evaluate energy-saving benefits comprehensively by combining production data (such as molding cycle time and material utilization rate), rather than just focusing on electricity meter readings. We currently have servo-driven and fully electric injection molding machines in stock, offering energy savings of up to 30%-60%, and support customized modifications.
For plastic injection molding, the mold is crucial. The mold must be precise, and the dimensions must be just right.Let's talk about plastic raw materials.
Pressure during injection molding includes both plasticizing pressure and injection pressure, which directly affect the plasticizing of the plastic and the quality of the product.
Injection molding is an engineering technology that involves transforming plastic into a useful product that retains its original properties. Important process conditions in injection molding are temperature, pressure, and corresponding action times that affect plastic flow and cooling.
Temperature Control:
Barrel Temperature: The temperatures that need to be controlled in the injection molding process include barrel temperature, nozzle temperature, and mold temperature. The first two temperatures mainly affect the plasticization and flow of the plastic, while the latter mainly affects the flow and cooling of the plastic. Each type of plastic has a different flow temperature. Even for the same type of plastic, the flow temperature and decomposition temperature will differ due to differences in average molecular weight and molecular weight distribution. The plasticization process of plastics also differs in different types of injection molding machines, thus requiring different barrel temperatures.
Plasticizing Pressure (Back Pressure): When using a screw-type injection molding machine, the pressure exerted on the molten material at the top of the screw as the screw rotates and retracts is called the plasticizing pressure, also known as back pressure. This pressure can be adjusted by the relief valve in the hydraulic system. During injection, the plasticizing pressure remains constant with the screw speed. Increasing the plasticizing pressure will increase the melt temperature but decrease the plasticizing speed. Furthermore, increasing the plasticizing pressure often results in more uniform melt temperature, more uniform colorant mixing, and the removal of gases from the melt. In general operation, the plasticizing pressure should be as low as possible while ensuring excellent product quality. The specific value varies depending on the type of plastic used, but it rarely exceeds 20 kg/cm².
Injection Pressure: In current production, almost all injection molding machines use the pressure applied to the plastic by the plunger or screw tip (converted from hydraulic pressure) as the injection pressure. The role of injection pressure in injection molding is to overcome the flow resistance of the plastic from the barrel to the mold cavity, provide the rate of molten material filling, and compact the molten material.
Injection pressure is divided into injection pressure and holding pressure. Typically, it consists of 1 to 4 stages of injection pressure + 1 to 3 stages of holding pressure. Generally, the holding pressure is lower than the injection pressure. It is adjusted according to the actual plastic material used to achieve optimal physical properties, appearance, and dimensional requirements.
