RJG 211M18, Product Manual

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Piezoelectric Load Washer Sensor 211M18 | Product Manual 2
OPERATION
LOAD WASHER SENSORS
The piezoelectric load washer sensor is
placed in the ejector retainer plate behind
the ejector sleeve. The ejector sleeve
core pin extends through the sensor and
sleeve. When the mold clamps and plastic
is injected, pressure is transferred from
the ejector sleeve onto the load washer.
The load washer measures the force, and
calculates the pressure based on the scale.
The accuracy of the sensor is dependent
upon the scale. The sensor is programmed
for 125 or 500 lb. as full scale, depending
upon sensor ordered. The eDART
computes a scale factor based on the
full scale value while pressure is being
applied.
PIEZOELECTRIC SENSORS
Piezoelectric sensors use quartz crystals
to measure the deformation, or change in
resistance of the force over the sensor. The
measurement is carried through the sensor
cable to a sensor adapter mounted on the
outside of the mold.
Piezoelectric quartz crystals contain
balanced negative and positive electrical
charges which are not symmetrically
arranged. When force is applied to the
piezoelectric crystal, the positive and
negative atoms are deformed, pushing
some of the atoms closer or further apart
and causing electrical charges to occur.
The sensor adapter is connected to
the RJG, Inc. eDART or CoPilot system,
which records and displays the sensor’s
measurement for operator aid in process
monitoring and control.
OUTPUT
PRESSURE
PRESSURE
PIEZOELECTRIC SENSOR OPERATING PRINCIPLE
EXCITATION