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Cavity balance improvement for injection molded parts via automated flow leader generation

  • Felipe Porcher EMAIL logo , Paul Borger , Georg F. Gruber , Falk Rohnstock and Dietmar W. Auhl
Published/Copyright: June 6, 2025
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Abstract

Better injection molded part quality can be achieved with a more balanced filling of the single mold cavity. Furthermore, a more homogeneous cavity pressure distribution results in less overpacked regions contributing to an overall lower pressure difference between gate locations and end of fill regions (Lam, Y. and Seow, L.W. 2000). Different process design parameters can affect the melt filling pattern inside the cavity, most notably the gate location, injection speed as well as geometrical constrains and accelerators, known as flow deflectors and flow leaders, respectively. However, determining its geometric parameters such as path, length, and cross-section is not a straightforward task. To address this problem, we developed an automated flow leader generation routine that uses injection molding simulations to determine the longest flow path along which the thickness of the part will be gradually increased, ultimately reducing the overall melt flow resistance. Our flow leader generation approach is based on the work of Seow, L. and Lam, Y.C. (1997) and Lam, Y. and Seow, L.W. (2000). However, in contrast to the principle used by Lam and Seow, the thicker portion of our flow leader is near the injection location, thus exploiting the higher injection pressure. We applied our approach to a demonstrator part to keep track of the fill pattern improvement. The highest fill time difference on the part’s boundaries, called fill time delta, was chosen as a measure for the cavity balance. To validate our method, an injection molding tool for the demonstrator part was manufactured and experiments were performed. We manufactured one unmodified cavity and one flow leader cavity generated with our method. Finally, we were able to demonstrate that our automated flow leader generation method improved the cavity balance both in simulation as well as in experiments, while simultaneously reducing the maximum injection pressure.


Corresponding author: Felipe Porcher, Department of Polymer Materials and Technologies, Technical University of Berlin, Ernst-Reuter-Platz 1, 10587, Berlin, Germany, E-mail:

Acknowledgments

The authors would like to extend their gratitude to Gino Wybranietz, Konstantin Jakob and Bartlomiej Piotrowski from the BSH Hausgeräte GmbH, as well as Oliver Löschke from the PTK department at TU Berlin.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: LLM, AI or MLT tools where used with the sole purpose of improving language.

  5. Conflict of interest: The author states no conflict of interest.

  6. Research funding: None declared.

  7. Data availability: Not applicable.

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Received: 2024-12-08
Accepted: 2025-04-05
Published Online: 2025-06-06
Published in Print: 2025-07-28

© 2025 Walter de Gruyter GmbH, Berlin/Boston

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