Analysis of Whitening Phenomenon in Injection Molded Products and Corresponding Solutions
In the field of injection molding, the whitening phenomenon of products is a problem that cannot be ignored, as it not only affects the appearance quality of the products but may also impair their mechanical properties. So, what factors lead to the whitening of injection molded products?
I. Analysis of the Causes of Whitening Phenomenon
Firstly, improper force control during the demolding process is one of the important reasons for the occurrence of whitening. When the demolding force is too large or the demolding is poor, the ejector pins will exert excessive pressure on the products, leading to localized stress concentration and the whitening phenomenon. In addition, when the products are subjected to excessive loads, they are also prone to whitening due to uneven internal stress distribution. It is worth mentioning that excessive demolding force caused by poor demolding is often the direct cause of the whitening phenomenon, and whitened products are likely to crack when subjected to slight external forces.
II. Effective Solutions to the Whitening Problem
To address the whitening phenomenon, we can make improvements from the following aspects:
Adjust the Injection Pressure: Appropriately reducing the injection pressure can reduce the internal stress of the products during the molding process, thereby reducing the risk of whitening.
Improve the Surface Finish of the Mold Cavity: Improving the surface finish of the injection mold cavity helps to reduce the friction during demolding, reduce damage to the products, and thus reduce the occurrence of the whitening phenomenon.
Optimize the Demolding Design: The product design should ensure sufficient draft angles, and the ejector pins should be arranged balanced and reasonably to ensure smooth demolding and avoid localized excessive force leading to whitening.
III. The Impact of Material Differences on the Whitening Phenomenon
Different materials exhibit different characteristics during the injection molding process. For example, ABS material is more prone to whitening due to its specific physical and chemical properties. At the same time, plastic materials with poor flowability are prone to defects such as weld lines during the injection process, which often accompany the whitening phenomenon.
IV. Precautions in the Injection Molding Process
Consider the Whitening Phenomenon in Post-processing: During the post-processing of ABS plastics, the possible whitening phenomenon of the products should be fully considered, and corresponding preventive measures should be taken.
Avoid Weld Lines Caused by Release Agents: Injection molded products are prone to weld lines that can easily separate due to release agents, which increases the risk of whitening to some extent and must therefore be avoided.
Risk of Damage at Weld Lines: Areas with weld lines are often prone to damage and other phenomena, which need special attention in product design and production.
Distinguish Between Weld Lines and Cracks: To accurately distinguish between weld lines and cracks, ink can be applied to the products for quick differentiation.
Prevention and Control of Defects at Weld Lines: Defects such as flash are prone to occur at weld lines, but concave marks rarely appear. During production, prevention and control of these defects should be strengthened to ensure product quality.
In summary, the whitening phenomenon of injection molded products is a complex and diverse problem that requires comprehensive consideration and solution from multiple aspects. By optimizing the demolding design, adjusting the injection pressure, improving the surface finish of the mold cavity, and paying attention to material differences and details in the processing process, we can effectively reduce the occurrence of the whitening phenomenon and improve the quality and stability of injection molded products.
