A Numerical Study on the Effect of Gate Position to the Structural Integrity of Plastic Injection-Molded Biomedical Implants

Optimizing the injection molding process for making biomedical implants is essential to avoid defects that impact patient safety and implant performance. This study examines how different gate positions affect defect rates in injection-molded polyether ether ketone (PEEK) pedicle screws, using numerical modeling to analyze melt flow, cavity pressure, sink mark depth, warpage, and Von Mises stress across four gate configurations. The findings show that gate position significantly influences structural integrity, with strategically placed gates reducing defects by promoting uniform flow. Gate configuration 2 was optimal, yielding minimal sink depth, low warpage, and low stress, while configuration 4 was the least effective as it was associated with higher values of defect rates. Carefully selecting gate positions can enhance the quality and reliability of biomedical implants.