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30.3 Flash Troubleshooting  287



































          Figure 30.5  Poor velocity to pressure response: note undershoot followed by overshoot in
                    pressure




          30.3.2„ Flash Troubleshooting Mold Issues


          Mold causes may include:
             ƒ Parting line damage
             ƒ Vent depth
             ƒ Trapped plastic
             ƒ Support
             ƒ Erosion
             ƒ Slide deflection
             ƒ Mismatch
             ƒ Cavity balance

          30.3.2.1„ Mold: Parting Line Damage
          One of the keys to avoiding flash is the requirement of a mold to have a robust shut
          off between the halves. If the parting line of a mold becomes damaged the shut off
          between the mold halves will not be sufficient to keep the plastic in the mold.
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