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Runner sizing and weld line positioning for plastics injection moulding with multiple gates

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Abstract

Weld line and warping are two critical defects for injection-moulded part. If weld lines are unavoidable due to multiple gates in a moulding, they should be positioned in the non-critical region. Instead of using flow leaders and deflectors to control the locations of the weld lines, this paper presents an approach to specify the locations of the weld lines by sizing the runners in a multi-gated injection moulding with the optimum gate locations. The methodology consists of three steps: partitioning the moulding into sub-mouldings based on the specified weld line location, determining the optimum gate location in each sub-moulding by minimizing the injection pressure and repositioning the weld lines to the desired locations by varying the runner sizes. Two examples are used to illustrate the approach.

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Acknowledgement

The authors would like to acknowledge the support of Moldlfow Pty Ltd and the Ministry of Education, Singapore.

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Authors and Affiliations

  1. School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore

    M. Zhai, Y. C. Lam & C. K. Au

Authors
  1. M. Zhai
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  2. Y. C. Lam
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  3. C. K. Au
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Corresponding author

Correspondence to C. K. Au.

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Zhai, M., Lam, Y.C. & Au, C.K. Runner sizing and weld line positioning for plastics injection moulding with multiple gates. Engineering with Computers 21, 218–224 (2006). https://doi.org/10.1007/s00366-005-0006-6

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  • DOI: https://doi.org/10.1007/s00366-005-0006-6

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