Development of a novel microforce-generating machine based on a force generation method using electromagnetic force

Herein, we report the development of a microforce-generating machine using electromagnetic force based on the principles of a Kibble balance to establish microforce traceability for ensuring the reliability of microforce measurements. We proposed a rotary-type microforce-generating machine using a combination of a balancing arm, a coil, and magnets. The microforce was generated through the balancing arm from the electromagnetic torque acting between the coil and magnets. The device eigenvalue, which served as the proportionality factor associated with the magnetic and geometric properties, was evaluated experimentally. The relationships between the eigenvalue and the temperature of the neodymium magnets, the rotation direction of the neodymium magnets, and the inclination of the balancing arm were discussed. The repeatability and reproducibility of the realized microforce were evaluated at force steps of 10 and 20 mN, and they were in the range of 3.8 x 10(-5)-3.9 x 10(-4). We demonstrated that a microforce transducer could be calibrated using the proposed machine.