In the field of medical injection molding, streak issues are extremely common quality problems during production. They not only affect the aesthetic appearance of products but may also pose potential threats to product performance and quality. However, don't worry. A set of comprehensive and effective countermeasures will be introduced in detail below.

Strictly Control Raw Materials to Eliminate Impurity Risks

Raw materials are the foundation of injection molding. Their quality directly impacts the quality of the final products. First, carefully check whether there are impurities mixed in the raw materials or if raw materials from different batches are used together. Different batches of raw materials may have slight differences in composition and performance, and mixing them can easily lead to streak issues. At the same time, ensure that the dryness of the raw materials strictly meets the requirements. Since the moisture in the raw materials will vaporize during the injection molding process, causing uneven plastic flow and resulting in streaks, sufficient drying treatment of the raw materials before production is crucial.

Precisely Adjust Temperatures to Ensure Uniform Plastic Melting

Temperature plays a key role in injection molding. Carefully check the temperature settings of the injection molding machine, including the barrel temperature and mold temperature. If the temperature is too high, the plastic will decompose excessively, generating gases and making the plastic flow unstable, thus forming streaks. If the temperature is too low, the plastic will not melt sufficiently, resulting in poor fluidity and also leading to streak formation. Therefore, it is necessary to adjust the temperature appropriately according to the type of plastic used and the product requirements to ensure that the plastic melts uniformly in the barrel, laying a good foundation for the subsequent molding process.

Reasonably Adjust Pressure and Time to Ensure Uniform Filling

Injection pressure and injection time are important factors affecting the flow and filling of plastic in the mold cavity. If the injection pressure is insufficient or the injection time is too short, the plastic will not be able to flow and fill the mold cavity sufficiently and uniformly, resulting in streaks on the product surface. On the contrary, excessive pressure or too long a time may lead to over-filling of the plastic and the formation of flash and other problems. Therefore, it is necessary to adjust the injection pressure and injection time reasonably according to the shape, size, and plastic properties of the product to enable the plastic to flow smoothly and uniformly in the mold cavity and achieve perfect filling.

Pay Attention to Mold Conditions and Repair Surface Defects

The mold is the "matrix" for injection molding, and its surface quality directly affects the appearance of the product. Carefully check whether the mold surface is smooth and free of scratches, wear, or damage. Surface defects on the mold will cause uneven plastic flow during the filling process, resulting in streaks. Once problems are found on the mold surface, they should be repaired or replaced in a timely manner. For minor scratches or wear, methods such as grinding and polishing can be used for repair. For severe damage, a new mold should be replaced to ensure the surface quality of the product.

Strengthen Equipment Maintenance to Eliminate Unstable Factors

The injection molding machine is the core equipment for production, and its operating status directly affects product quality. Regularly maintaining and servicing the injection molding machine to ensure that the equipment is in good operating condition is an important measure to prevent streak issues. If the equipment has faults or wear, such as screw wear or hydraulic system leakage, it will lead to unstable factors during the injection molding process, such as pressure fluctuations and uneven temperatures, resulting in streaks. Therefore, a complete equipment maintenance system should be established to regularly inspect, clean, lubricate, and repair the equipment, promptly identify and solve potential problems, and ensure the stable operation of the equipment.

Continuously Optimize Processes to Improve Product Quality

The optimization of process parameters is a process of continuous exploration and improvement. By conducting experiments and analyzing data, continuously optimizing the injection molding process parameters, such as injection speed, holding pressure time, and cooling time, can effectively improve product quality and reduce the occurrence of quality problems such as streaks. For example, appropriately increasing the injection speed can enable the plastic to fill the mold cavity more quickly, reducing the cooling time during the flow process and lowering the probability of streak formation. Reasonably adjusting the holding pressure time can ensure that the plastic is fully compacted in the mold cavity, improving the density and surface quality of the product. When optimizing process parameters, it is necessary to combine the actual situation of the product and production experience, conduct multiple experiments and analyses, and find the best process combination.

In conclusion, to address the streak issues that occur during medical injection molding, a comprehensive analysis and treatment from multiple aspects such as raw materials, temperature, pressure, time, mold, equipment, and processes are required. By comprehensively applying the above measures, streak issues can be effectively solved, and product quality can be significantly improved.