Custom Injection Molding
Custom injection molding technology first heats and melts plastic raw materials through mechanical equipment, injects them into molds, and after cooling and solidification, obtains products that are completely consistent with the mold cavity.
Injection Mold Maker | Processing Technologies
Injection mold maker aims to design the most suitable and advanced injection molds for customers, providing the most comfortable injection molding services. The company is equipped with the best designers and experienced mold operators, as well as modern drawing equipment and CNC machinery. The injection mold maker will communicate with customers, understand their needs, and provide the most suitable and efficient design solution according to their requirements. The mold is the first and most important step before the start of the entire custom injection molding project, and the high-quality mold produced in this way can provide more convenience for the customer’s future production.
Process Composition of Injection Mold Maker
For the injection mold maker and user, both molds and injection molding machines are important tools for production, and the role of molds is even greater. The basic structure of injection molds can be divided into six parts: molding components, pouring system, guiding mechanism, molding device, temperature control system, and exhaust system. These six parts each play their respective roles and work together with injection molding machines to produce high-quality plastic products. If injection mold maker wants to produce high-quality molds, they need to pay attention to the design of each component.
Formed Components: The molded components of a mold form the plastic product, determining the size and structure of the molded part. The key to its performance is what injection mold maker needs to first understand. Usually, the formed parts are divided into Two Parts: the core and the concave mold. The core is responsible for the internal structure of the product, while the concave mold is responsible for the external structure of the product. The two can be separate parts or as a whole. Therefore, the injection mold maker should consider the characteristics of the product they want to produce when designing.
Pouring System: The channel through which plastic passes before entering the mold cavity after becoming molten is called the pouring system. The pouring system usually consists of a main flow channel, a diversion channel, a gate, and a cold material cavity. The processing technology of the pouring system has a significant impact on the quality, size, and production speed of plastic molded parts produced by the maker.
Guiding Institutions: The guidance mechanism of the mold mainly includes guide pillar guidance, positioning block guidance, and mold core positioning convex platform guidance. The setting of this system is mainly to ensure that the dynamic mold and fixed film of the mold can be aligned and withstand a certain amount of lateral pressure during opening and closing, avoiding the possibility of damage caused by the core entering the concave mold during mold manufacturing by makers, and ensuring the accuracy of the formed parts.
Demoulding Device: The core part of mold demolding is the ejection device, which is mainly composed of components such as the ejector pin, slider, inclined top, and air top. Manufacturers can consider using pneumatic, mechanical, or manual demolding devices based on the type of product during design. The pneumatic type is mainly able to provide uniform pressure, thereby reducing the risk of warping deformation during mold forming; The Mechanical type mainly uses connecting rods for demolding, but it is only suitable for the needs of simple instruments; The manual demolding structure is simple and the manufacturing cost is low, but it requires a lot of manual labor and has low production efficiency.
Temperature Control System: When makers process, the melting point of different plastic materials and the temperature required for processing and forming are different. In this case, a temperature control system needs to be set up in the mold. If the heating element is used to increase the temperature of the mold, the cooling element is used to reduce the temperature of the mold, and the temperature controller is used to control the operation of the heating and cooling elements to maintain a stable working state of the mold. The temperature control system is also very important in the formation of liquid silicone rubber.
Exhaust System: The exhaust system of the mold is mainly used to ensure the quality of injection molding services, reduce scrap rates, and discharge the bubbles generated during the injection molding process. If there is no exhaust system, it will cause excessive pressure inside the mold, resulting in high temperature and causing plastic decomposition or quality defects. By designing an effective exhaust system, the above problems can be effectively avoided and the quality of injection molded products can be improved.
Methods for Makers to Improve the Quality of Injection Molding Products
When evaluating the quality of injection molded products, important reference indicators for the injection mold maker are scrap rate and qualification rate. Only by reducing the scrap rate and increasing the qualification rate can the competitiveness of injection molded products in the market be improved. Improving the quality of injection molded products can be achieved by adjusting process parameters and optimizing raw materials.
Adjusting Process Parameters
- Makers can first adjust the screw parameters and select different screws for different plastic materials. For example, for amorphous plastics such as polyvinyl chloride (PVC) that have poor stability and a wide range of softening temperatures, a gradient screw with a longer compression period and smoother energy conversion during plasticization can be chosen; For crystalline plastics such as polyolefins and PA, mutation type screws with short compression sections and intense energy conversion during plasticization can be used. For other plastics, universal screws with strong adaptability can be chosen to avoid frequent replacement of screws and provide better injection molding services.
- Manufacturers can adjust the temperature parameters of raw materials during the production process, adjusting the melt temperature to be lower than the temperature of the material barrel, enhancing the fluidity of the molten plastic, and also preventing hot air from flowing into the mold, causing bubbles in the product.
- The injection pressure can be adjusted according to the customer’s product type, and sufficient pressure can make the plastic part closely adhere to the mold wall, thereby reducing the possibility of plastic part shrinkage. Especially for thin-walled injection molding with lower temperatures and products that require quick filling, both require higher pressure,
- Injection speed and screw forward speed. Under normal circumstances, excessive injection speed can easily lead to insufficient cooling of the previous product and the appearance of weld marks; If the injection speed is too slow, it can cause surface roughness and lack of luster. Manufacturers should consider the characteristics and accuracy requirements of the product when adjusting the speed.
- Determination of holding pressure and time. The most suitable holding pressure set by the manufacturer should be between the lowest and highest, which can prevent product shrinkage and the possibility of product cracking and bending. The magnitude of the holding pressure also affects the holding time, with higher pressure leading to longer holding times. For plastics with fast melting rates, a relatively short holding time can be set.
- Adjust the cooling time during the injection molding process. In the absence of defects in the product, the injection mold maker should consider the thickness of the finished product, and the cooling time should be as short as possible.
- The appropriate mold temperature is also a key factor in ensuring the normal flow and cooling of molten plastic. The temperature is generally determined based on the molding cycle and quality of the mold and should be set as high as possible to provide greater adjustment space in subsequent injection molding services.
Optimize Raw Materials
Manufacturers should consider the shrinkage rate of raw materials and analyze the reasons for shrinkage when selecting materials; Consider whether the raw materials used are crystalline or amorphous, that is, whether they are thermoplastic or thermosetting plastics; The temperature, shear rate, and pressure during the molding process affect the viscosity of plastic raw materials. It is necessary to choose the correct plastic raw materials for production to improve the quality of injection molded products and reduce scrap rates.
Maker's Maintenance of Injection Molds
Injection mold maker attaches great importance to the maintenance of injection molds, as the service life of injection molds is closely related to maintenance, and it also makes it difficult to avoid production delays and high maintenance costs.
Cleaning and Maintenance: Manufacturers and mold users carry out daily cleaning of molds, mainly focusing on whether the surface of the mold is free of oil stains, residues, etc., to ensure that the inside and outside of the mold are unobstructed.
Lubrication Treatment: The operator should regularly inspect areas with significant wear on the mold, such as sliding and guiding systems. Lubricants can be added to reduce friction and wear. The selection of lubricants should also be based on the material of the mold to prevent chemical reactions from damaging the mold and provide good injection molding services.
Rust Prevention Treatment: The rust prevention treatment of the mold can use rust inhibitors and lubricating oil to form a protective film on the surface of the mold, preventing rust from coming into contact with excessively humid air. When not in use, the mold should also be placed in a well-ventilated and dry environment.
Inspection and Maintenance: Each component and system of the mold should be carefully inspected and repaired to check for any damage and replace and repair according to the degree of damage, to maintain the normal use of the mold.
Maintenance of Shutdown Molds: Before the injection molding service is stopped, the cooling water circuit and cooling system must be closed first, and the residual water in the water circuit of the mold must be blown out to prevent rust caused by residue. Check whether there is any residual plastic or foreign matter on the surface of the mold, clean it thoroughly, and then evenly spray the rust inhibitor.
Timely Recording: After each inspection and repair, the manufacturer must make written records and properly store them to ensure good after-sales service.
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