Page 115 - Injection Molding Advanced Troubleshooting Guide
P. 115

12 Cavity Balance

















          Cavity balance is the measure of how evenly a multicavity mold fills. Figure 12.1
          shows four cavities from an eight-cavity mold with imbalance, and Figure 12.2
          shows the Moldflow predicted fill pattern. It is critical that in all phases of the
          molding process (first stage, second stage, cooling) all cavities are treated the
          same. Many defects can be directly linked to poor cavity balance including:
             ƒ Short shots
             ƒ Flash
             ƒ Sink
             ƒ Burns
             ƒ Voids
             ƒ Dimensional issues
             ƒ Warp
             ƒ Sticking
             ƒ Gloss


























          Figure 12.1  Eight cavity fill imbalance
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