Page 136 - Injection Molding Advanced Troubleshooting Guide
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13.5 Additional Monitoring Options 123
Changes in flow rate
Scale buildup in water lines
Changes to heat input from higher melt temperatures or faster cycle times
13.5 Additional Monitoring Options
With the ability to take any 0–10-V signal into process monitoring equipment
there are many opportunities to monitor details in the molding process or environ-
ment. Some options to consider include:
Dryer monitoring. Use an analog input device to take the temperature and dew
point of a dryer into process monitoring equipment. This can be a great way to
test dryer performance.
Melt temperature. An in-stream melt temperature device is an ideal piece of pro-
cess monitoring. Installation of an in-nozzle thermocouple that is within the
melt stream allows for measurement of actual melt temperature during the pro-
cess. Unfortunately, these thermocouples tend to not last long in the harsh envi-
ronment of the melt stream.
Water flow through the mold. Water flow is one of the key items to cooling rate of
the plastic. Monitoring the flow allows ongoing detection of any concerns relative
to this process parameter. Figure 13.11 shows an example of a typical digital flow
meter, and when purchased with output capabilities this unit can be connected
to process monitoring equipment.
Figure 13.11 Digital flow meter
