Injection mold injection device and maintenance

The injection device is a device that melts the resin material by heating and injects it into the mold. The resin is extruded from the material head into the barrel, and the melt is transported to the front end of the barrel through the rotation of the screw. In that process, the resin material in the barrel is heated under the action of the heater, and the resin is melted under the action of the shear stress of the screw, and the molten resin corresponding to the molded product, the main flow channel, and the branch flow channel is retained. At the front end of the barrel (called metering), the material is injected into the mold cavity by the continuous advancement of the screw. When the molten resin flows in the mold, the moving speed of the screw (injection speed) must be controlled, and the pressure (holding pressure) should be used after the resin fills the mold cavity. When the screw position and injection pressure reach a certain value, we can switch the speed control to pressure control.

How to maintain the injection mold?

1. The processing enterprise should first equip each pair of molds with a resume card to record and count its use, care (lubrication, cleaning, rust prevention) and damage in detail. Based on this, it can be found which parts and components have been damaged, the degree of wear, and the degree of wear. Provide information on finding and solving problems, as well as the molding process parameters of the mold and the materials used in the product, so as to shorten the test run time of the mold and improve production efficiency.

2. The processing enterprise should test the various properties of the mold under the normal operation of the injection molding machine and the mold, and measure the size of the final molded plastic part. Through this information, the existing state of the mold can be determined, and the cavity and core can be found. According to the information provided by the plastic parts, the damage status of the mold and the maintenance measures can be judged.

3. Focus on tracking and testing of several important parts of the mold: the function of ejection and guide parts is to ensure the opening and closing movement of the mold and the ejection of plastic parts. If any part is stuck due to damage, it will lead to production stoppage, so it should Always keep the mold thimble and guide post lubricated (the most suitable lubricant should be selected), and regularly check whether the thimble and guide post are deformed and surface damaged. Once found, they should be replaced in time; after completing a production cycle, the mold should be Professional anti-rust oil should be applied to the working surface, motion and guide parts, and special attention should be paid to the protection of the elastic strength of the bearing parts with gears, rack molds and spring molds to ensure that they are always in the best working condition; with the production Over time, the cooling channel is easy to deposit scale, rust, silt and algae, which reduces the cross-section of the cooling channel and narrows the cooling channel, which greatly reduces the heat exchange rate between the coolant and the mold and increases the production cost of the enterprise. Attention should be paid to the cleaning of the hot runner mold; for the hot runner mold, the maintenance of the heating and control system is helpful to prevent the occurrence of production failures, so it is particularly important. Therefore, after each production cycle, the belt heaters, rod heaters, heating probes and thermocouples on the mold should be measured with an ohmmeter. If they are damaged, they should be replaced in time and checked with the mold resume. Compare and keep records so that problems can be detected in a timely manner and countermeasures can be taken.

4. Pay attention to the surface maintenance of the mold, which directly affects the surface quality of the product, and the focus is on preventing rust. Therefore, it is particularly important to choose a suitable, high-quality and professional anti-rust oil. After the mold completes the production task, different methods should be adopted to carefully remove the residual injection molding according to different injection molding methods. Copper rods, copper wires and professional mold cleaning agents can be used to remove residual injection molding and other deposits in the mold, and then air dry. It is forbidden to clean hard objects such as iron wires and steel bars to avoid scratching the surface. If there are rust spots caused by corrosive injection molding, use a grinder to grind and polish, and spray professional anti-rust oil, and then store the mold in a dry, cool, and dust-free place.

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