1. Impact of cooling shrinkage problem
Cooling shrinkage is a common problem for injection molding precision parts after molding. If not properly handled, cooling shrinkage may cause part size deviation, deformation and even affect its function and assembly performance. For example, in the field of electronic equipment, the dimensional accuracy of precision parts is extremely high, and even a small shrinkage difference may cause the product to be unable to be assembled normally or its performance to deteriorate. Therefore, solving the cooling shrinkage problem is crucial to ensuring the quality of injection molding precision parts.
2. Optimizing injection molding process parameters
First, the impact of cooling shrinkage can be reduced by optimizing injection molding process parameters. Adjusting parameters such as injection molding temperature, pressure and speed can control the flow and filling of plastic melt in the mold, thereby affecting the degree of shrinkage during the cooling process. For example, appropriately lowering the injection molding temperature can reduce the thermal expansion of the plastic, thereby reducing the amount of cooling shrinkage. At the same time, reasonable control of the holding pressure and time can compensate for the shrinkage of the plastic during the cooling process and reduce the generation of shrinkage gaps. In addition, choosing a suitable injection molding speed can ensure that the plastic melt fills the mold evenly and avoid uneven shrinkage caused by local overheating or overcooling.
3. Improvement of mold design
Mold design also has an important impact on the problem of cooling shrinkage. A properly designed cooling system can speed up the cooling of parts and make the parts more uniform during the cooling process, thereby reducing shrinkage differences. For example, increasing the number and distribution density of cooling water channels can improve cooling efficiency and reduce the temperature gradient of parts. In addition, the selection of the gate position and number of the mold is also critical. A reasonable gate design can make the plastic melt flow more evenly in the mold and reduce the shrinkage problem caused by unbalanced flow. At the same time, the use of appropriate demolding mechanisms and mold materials can reduce the stress of parts during demolding and reduce the risk of deformation.
4. Application of post-processing methods
In addition to optimizing the injection molding process and mold design, some post-processing methods can also be used to solve the problem of cooling shrinkage. For example, annealing the parts can eliminate residual stress inside the parts and reduce deformation. Annealing at a specific temperature for a period of time can rearrange the plastic molecules and improve the dimensional stability of the parts. In addition, for some precision parts with very strict dimensional requirements, mechanical processing can be used for fine-tuning to compensate for the dimensional deviation caused by cooling shrinkage. However, mechanical processing needs to be operated with caution to avoid damage to the parts or affecting their performance. In a word, by comprehensively applying measures such as optimizing injection molding process, improving mold design and adopting post-processing methods, the cooling shrinkage problem of Injection molding precision parts can be effectively dealt with and the quality and precision of parts can be improved.
