Page 358 - Injection Molding Advanced Troubleshooting Guide
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354   36 Part Sticking on Ejector




               36.3.4.4„ Material: Viscosity
               If the viscosity of the material changes for any reason it can impact how the plastic
               is packed and cooled in the mold. Lower-viscosity (easier flowing) material will
                 allow for better transfer of pressure throughout the cavity, which can impact shrink
               and cooling. Bear in mind that the incoming viscosity of the material may change
               but changes in the process will also influence viscosity. Always verify the follow-
               ing:
                  ƒ Melt temperature
                  ƒ Barrel temperatures
                  ƒ Back pressure
                  ƒ Screw recovery rate
                  ƒ Barrel size
                  ƒ Intensification ratio
                  ƒ Fill rate
               Any of the above process conditions may lead to a viscosity change that could im-
               pact how the part sticks in the mold.
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