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Vietnamese Due to the varying materials used in each product, defects occasionally occur in the IMD injection molding process. For instance, rigid plastic products often exhibit ripple marks. So, what causes these ripple marks, and how can they be effectively resolved?
Causes of Ripple Marks in Injection Molding
In rigid plastics like PS, dense ripple patterns often form near the gate, centered around it—this phenomenon is known as ripple marks. The primary cause is the high viscosity of the melt, which leads to sluggish flow during mold filling. When the leading edge of the melt contacts the cavity surface, it cools and contracts quickly, while the following melt expands and continues forward. This alternating effect results in the formation of ripple marks on the surface.
Solutions for Eliminating Ripple Marks in Injection Molding
- Increase Barrel and Nozzle Temperatures: Raise mold temperatures simultaneously to reduce melt viscosity.
- Increase Injection Pressure and Speed: Enhance pressure and speed to ensure the melt fills the mold cavity quickly.
- Optimize Runner and Gate Dimensions: Design runners and gates appropriately to prevent excessive flow resistance.
- Ensure Proper Mold Ventilation: Set sufficiently large cold wells to improve ventilation.
- Avoid Overly Thin Product Design: Design the product with adequate thickness to prevent ripple marks due to thinness.
DAYIN Plastic Products Co., Ltd. is a high-tech enterprise specializing in product R&D, design, manufacturing, and sales services, offering one-stop solutions. Since its establishment in 1989, we have focused on mold making, injection molding, post-processing, and electronic assembly. In addition to contract manufacturing, we develop our own products and support clients with private label production. Our facilities cover 50,000 square meters, with 30 years of mold development experience, over 50 R&D staff, and more than 100 injection molding machines, dedicated to delivering high-quality manufacturing services to our clients.