SOLIDWORKS Plastics Runner Optimization

SOLIDWORKS Plastics contains many useful features like, sink detection, weld line locations, air trap prediction, and many more.  One of the best tools that Plastics professional offers is Optimized Runner Balancing.  What is Optimized Runner Balancing?  Let’s take a step back and talk about what SOLIDWORKS Plastics Simulation is and what it is used for.

SOLIDWORKS Plastics Simulation is a manufacturability software that helps plastic part designers, plastic injection mold designers, and injection mold shops gain insight into the flow, pack, warp, and cool phases of the injection process.  With injection molds it is a common practice to mold like parts or parts that are meant to mate together in the same mold.  This practice helps keep the same color pigment and mechanical properties in each component.

The molten plastic is delivered to the cavities via channels called runners.  When the cavities are different in size by volume the cavities will fill unevenly.  The hard part is getting the cavities to fill completely at the same time.  Optimized runner balancing does this step for you.

The test component is a smoke alarm body consisting of the top and bottom casing.  The top and bottom are different volumetric sizes and varying wall thicknesses.  The runner system can be modeled or virtually applied.  In this case study I used the virtual runners.  These are applied based on size inputs the user specifies.  A 2D or 3D sketch is used to apply the runner system too.

Runner Balancing1

Runner Design 1

Runner Design 2

The runner system initial setup is an even size for all four cavities.  This proves to be inadequate as the cavities fill unevenly.  Plastics proves this as shown in the plot below.

Unbalanced runners

Un Balanced

The brown area is the unfilled section of the cavity.

The optimized runner balancing is tuned on in the “Runner Balancing” option in the plastics tree.  The user specifies the range of sizes for the runners and interpolates until the cavities fill evenly.  The revised size distribution is shown below and the balanced output.


Balanced Runners


Plastics Professional takes the guess work out of balancing a multi-cavity runner system.  This saves time and money for the mold/part designer.  Like the optimization in SOLIDWORKS Simulation and SOLIDWORKS Flow Runner Optimization proves to be an invaluable tool.

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