Newsletter: Torque tool calibration
In order to set the click point or to check the right setting of torque wrenches or torque srew drivers, measuring instruments like the Alluris ToolTorqueTester TTT-300 are used, which replace the counter moment of the tight screw connection. These test and measuring instruments are predominantly used in assembly processes to assure the quality of a connection which has a major impact to the quality of the final product. Nevertheless the measuring technology used in the tool torque testers allows also to utilise the tester for anual calibration of torque tools if the following 4 essential topics are considered.
The standard EN ISO 6789:2003 describes the general requirements for the calibration of manual operated torque tools. Of importance is how the load is applied correctly and the torque is accelerated in order to achive a good reproducibility of the measuring results. This is almost impossible without the right tools, as on one hand side the tolerances for conformal angle to apply the load are very tight and on the other hand the timing for torque (moment) acceleration are defined very precisely. The manual test stands FMT-920 for torque wrenches, FMT-921 for torque screw drivers und FMT-922 as combination for both are designed in a way to ease the use and to fullfill the requirements for a correct calibration according to the standard.
EN ISO 6789:2003 also defines the procedure of the calibration always related to the specific torque tool type. TTT_Certify is a software tool to support fullfilling the procedures as described. All different torque tool types as classified in the attachment to the standard are filed in the software and build the spine for the data base of all your torque tools, which can easily be administrated on your own. The programm itself leads step by step through the calibration process records the measuring data and calculates the deviation and uncertainties to approve the conformity of your torque tool.
Pic.: Screenshot Main Menu TTT_Certify
TTT_Certify also generates a calibration certificate in full accordance to the instructions as per EN ISO 6789:2003. All formulas are part of the comprehensive programm to calculate the deviation and uncertainty of measurement. All details of the calibration are considered in the automatically rendered PDF.
The tracibility of the calibration device, consisting of the test stand and the mounted measuring instrument, is confirmed with a calibration certificate according DAkkS-DKD-R 3-8 which can be issued in our calibration laboratory. The transfer standard up to 50 Nm are associated directly with a calibration according DAkkS-DKD-R 3-7 to the standards of PTB the german national metrology institute. The tracibility data is filed in the tool torque tester with the calibration certificate number and the date of calibration, and will be readed each time TTT_Certify issues a new certificate.
Save money and time and calibrate tool torques on your own.