Calibration of torque measurement instruments (mainly torque wrenches and torque testers), even if widely used in the automotive, aviation and building industry, receives less attention than other types of instruments (for example, length measurement instruments). Very few laboratories offer calibrations services for torque measurement instruments, compared to length measurement, pressure, and so on.
All car manufacturers have developed internal measurement systems to measure torque (for example, braking systems, frictions, etc.), but out of these laboratories the specific situation for torque calibration is still unclear.
Since torque is given in Nm, the usual way to calibrate such instruments is to use a torque balance, set the torque tool at the target value (i.e. 40 Nm) and apply reference weights (N) until the requested KP (Click Point) is reached. The difference between the nominal KP (on the wrench) and the true KP (measured by the sensor on the torque balance) should be less than 4% or 6%, depending from tool type.
Regular torque calibration guarantees the operator repeatable accuracy and adherence to international standards. It also ensures torque equipment operates optimally and can highlight potential tooling problems before they arise perhaps due to torque tool wear or broken components.
Here at Nusantara Technologies we provide quality torque calibration service for our customers with the aid of highly trained technicians.
Our Calibration Capabilities:
- Torque Wrench up to 1,500 Nm.
- Torque Screw Driver
- Torque Multiplier
- Torque Transducer
Calibration of Torque Wrench
Figure at left defines the raw idea on how toque wrench calibration is done. Torque Wrench will act as Unit Under Test (UUT) and placed on standard transducer to measure the torque. Using our procedure that complies with ISO 6789, we will ensure our end user will have confidence in every measurement.
Torque wrenches are generally divided into two types. One is beam type and the other is click type. If calibration is not performed, general wear and tear can have an effect on the internal workings of the device, ultimately leading to incorrect readings every time the torque device is used. To accurately measure the output of your torque wrench, we take five readings for every test we perform. This enables us to determine if your torque wrench conforms to manufacturer specifications and also accurate.
For indicating torque tools (Type I), prior to testing, one pre-loading up to the maximum value must be carried out in the operating direction to be tested and after releasing the load, the pointer or electronic indication must be set to zero. For testing in any other operating direction, this procedure shall be repeated. For setting torque tools (Type II), prior to testing, five releases without measurement must be carried out at the maximum value (nominal capacity of the torque tool) in the operating direction to be tested.
For testing in any other operating direction, this procedure shall be repeated. Torque wrenches are calibrated at the values of 20%, 60% and 100% of their maximum value (or of the nominal value in case if Type II, Class B or E wrenches). Torque wrenches are generally well used mechanical devices that require regular calibration.