Improved working efficiency of force standard machine by separating alternative weight stacks

Renovation work has been carried out to separate the 3 kN / 500 N dead-weight type force standard machine (DWM) at the National Metrology Institute of Japan. Two loading frames and a common structural frame were newly manufactured. No significant changes were observed in the calibration results of several force transducers before and after the renovation; in some cases, there has even been improvement in terms of repeatability and reproducibility of the calibration results. The renovation has made it possible to operate the two weight stacks simultaneously and to improve the working efficiency of calibration, while maintaining the reliability of the DWMs as the national force standards.