Coordinate Measuring Machine Restraint Fixture Calibration for Thermoplastic Assemblies
Calibrate CMM restraint fixtures by matching datum locators to nominal CAD and regulating clamping forces to eliminate non-rigid part deflection.
Torque Limiter
Meaning
Protective mechanical couplings in drive assemblies prevent damage to downstream components by slipping or disengaging when a preset torque threshold is exceeded. Integrating a torque limiter into the drivetrain of an extruder or moulding machine protects the motor and gearbox from sudden overloads caused by mechanical jams or frozen polymer. This device is essential for heavy industrial machinery.
Friction Control
Most torque limiters use friction discs, spring loaded balls or shear pins to transmit the rotational force. When the resistance of the driven shaft exceeds the spring force, the torque limiter slips, interrupting the power flow and preventing the gears from stripping. This slipping action continues until the motor is stopped or the overload is cleared.
Extrusion Protection
In polymer extrusion, unmolten resin or foreign metal objects can jam the screw, causing a sudden spike in torque. The torque limiter protects the screw from twisting or snapping by immediately decoupling it from the drive motor. This rapid action prevents expensive damage and minimizes the downtime required to clear the blockage and restart the line.
Maintenance Procedure
Regular testing of the torque threshold is necessary to ensure the device slips at the correct value. Over time, friction plates can wear or spring tension can drift, which would alter the slipping point of the torque limiter. Routine maintenance and calibration according to the manufacturer’s specifications ensure that the device remains fully operational and ready to protect the machinery from unexpected mechanical failures during high volume production runs, saving thousands of dollars in replacement parts and lost productivity.