In the production process of plastic molded parts, coconut shell speaker, controlling the shrinkage deformation of plastic is a key link to ensure product quality.
First, it is crucial to choose plastic materials reasonably. Different types of plastics have different shrinkage rates. For plastic molded parts of coconut shell speaker, plastics with low shrinkage rates and good stability should be selected according to the specific requirements of the product. For example, in some parts with high dimensional accuracy requirements, materials such as polystyrene (PS) or polycarbonate (PC) can be selected. Their shrinkage rates are relatively low, which helps to reduce shrinkage deformation. At the same time, attention should be paid to the batch stability of the material to ensure that the material properties of each batch are consistent and avoid the instability of shrinkage deformation caused by material differences.
Secondly, optimizing mold design is an important means to control shrinkage deformation. The structural design of the mold should take into account the flow and shrinkage characteristics of the plastic during the molding process. For example, the position and number of gates should be reasonably set so that the plastic can evenly fill the mold cavity to avoid local shrinkage differences caused by uneven mold filling. In addition, the cooling system of the mold also needs to be carefully designed to ensure uniform cooling. A circulating cooling water channel can be used to keep the mold surface temperature consistent and reduce shrinkage deformation caused by different cooling rates. For products with complex shapes such as coconut shell speakers, appropriate demolding mechanisms can also be set in the mold to avoid additional deformation of the molded parts during demolding.
Furthermore, precise control of molding process parameters is key. Parameters such as injection pressure, injection speed, holding pressure and holding time have a direct impact on the shrinkage deformation of plastics. During the production process, the best combination of process parameters should be determined through experiments and debugging. Generally speaking, appropriately increasing the injection pressure and holding pressure can increase the density of the plastic in the mold cavity and reduce shrinkage. However, excessive pressure may also cause internal stress in the plastic, causing deformation. Therefore, it is necessary to find a suitable balance point. At the same time, the injection speed and holding time should be reasonably controlled so that the plastic can be fully cooled and shaped in the mold to avoid shrinkage deformation caused by premature demolding.
In addition, pretreatment of plastic raw materials can also help control shrinkage deformation. For example, for plastics with strong hygroscopicity, such as polyamide (PA), drying treatment is required before molding to remove moisture. Otherwise, moisture will cause hydrolysis of the plastic during the molding process, affecting its performance and increasing the possibility of shrinkage deformation. The drying temperature and time should be strictly controlled according to the type and characteristics of the plastic to ensure that the raw materials reach the best molding state.
After the plastic is molded, appropriate post-processing processes can also improve shrinkage deformation. For example, heat treatment or humidity treatment can be used. Heat treatment can eliminate the internal stress inside the plastic, further relax and stabilize the molecular chain, and thus reduce shrinkage deformation. Humidity treatment is suitable for some plastics that are easy to absorb moisture. By allowing the molded parts to absorb a certain amount of water, it can reach a balanced state and avoid dimensional changes due to moisture absorption during use.
In addition, the temperature and humidity of the production environment also have a certain effect on the shrinkage deformation of the plastic. Keeping the temperature and humidity of the production environment stable can reduce the fluctuation of plastic performance caused by environmental factors. Generally speaking, the temperature should be controlled at 20℃ - 25℃, and the relative humidity should be 40% - 60%.
Finally, quality inspection and feedback mechanism are important guarantees for controlling shrinkage deformation. During the production process, the molded parts should be regularly inspected for size and appearance to detect shrinkage deformation problems in a timely manner. Once a problem is found, the cause should be analyzed in a timely manner, and the process parameters or molds should be adjusted. Through continuous optimization and improvement, the dimensional accuracy and quality stability of products are gradually improved.
