Page 380 - Injection Molding Advanced Troubleshooting Guide
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378 40 Short Shot
40.2 Short Shot Troubleshooting Chart
Table 40.1 shows the short shot troubleshooting chart.
Table 40.1 Short Shot Troubleshooting Chart
Molding Process Mold Machine Material
light fill only weight venting non-return valve viscosity shift
pressure limited cavity balance wrong nozzle low moisture content
low fill velocity plugged gate or hot tip worn barrel inconsistent material
feed
low second-stage stuck plastic machine performance unmelts
pressure
velocity to pressure low hot runner nozzle leak contamination
transfer temperatures
no cushion leaking hot runner
manifold
no back pressure
low melt temperature
low mold temperature
40.3 Short Shot Troubleshooting
When dealing with short shots focus on why there is a lack of plastic or plastic
pressure at the location of the short shot. Use the STOP method to systematically
work through the potential root causes.
40.3.1 Short Shot Troubleshooting Molding Process Issues
Potential molding process related causes are:
Light fill only weight
Pressure limited
Low fill velocity
Low second-stage pressure
Velocity to pressure transfer
No cushion
