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Runner Balance analysis

    Table of contents
    1. 1. How it works
        1. 1.1.1. Topics in this section

    The Runner Balance Analysis is used to determine the optimum volume for the sections of the runner system. This analysis ensures that the part fills evenly and there is an acceptable pressure magnitude in the cavity, minimizing runner volume.

    The Runner Balance analysis is supported for the following analysis technologies:

    • Dual Domain
    • 3D
    Note Gates are not automatically sized by the Runner Balance analysis.

    How it works

    Runner systems should be balanced to reduce overpacking during the filling phase. During a Runner Balance analysis, the runner system dimensions are altered to ensure that parts fill simultaneously and the volume of the feed system is minimized.

    A well-balanced runner system can make considerable savings in material usage. Before performing a Runner Balance analysis, you should check the Fill analysis and ensure that you are satisfied with each of the following:

    • Molding conditions.
    • Gate locations.
    • Cavity balance.

    The Runner Balance analysis is for a model with an attached runner system. A runner system that is added after a Fill+Pack analysis helps you balance the cavities. The aim is to achieve runner dimensions with the following characteristics:

    • The same pressure drop in all flow paths, which fills all cavities simultaneously
    • Controlled shear heating, which minimizes stress levels without using a high melt temperature
    • Minimized volume of runner material relative to cavity volume, which achieves the highest possible pressure drops in the runner system
    TipIt is useful to perform a Runner Balance analysis without runner balance constraints, and then use these new dimensions as the basis on which to set constraints. This reduces the risk of over-constraining a part and restricting the program's ability to provide a balanced runner system design.

    Topics in this section

    • Runner Balance analysis (Procedure)

      The Runner Balance analysis is used to determine the optimum volume for the sections of the runner system.

    • Runner balance constraints

      Runner balance constraints are an optional analysis input that you can set for a Runner Balance analysis.

    • Runner balance derivation

      Runner balancing is performed as a conditional minimization of a criterion function, which is calculated by using the results of a simplified analysis.