Page 93 - Injection Molding Advanced Troubleshooting Guide
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8.6 Velocity to Pressure Transfer 77
and as the zones are heating the thermocouple will not respond, which will cause
the controller to keep sending current to the zone. Figure 8.16 shows a nozzle
with failed heater bands captured in an infrared (IR) image.
Figure 8.16 IR thermal image of extended nozzle with heater bands not working.
Examine thermocouples for full insertion into thermocouple wells. Also verify
that heat bands are tight against the barrel. Loose heater bands will have an air
gap that will restrict heat transfer. See Figure 8.17.
Figure 8.17 Nozzle cross section showing fully seated thermocouple.
