A Novel Mechanical-Mechanism Enhanced Thermomagnetic Tweezer Demonstrating Gripping of Ferromagnetic and Non-Ferromagnetic Objects

In this article, we demonstrate a mechanical-mechanism enhanced thermomagnetic tweezer. The tweezer which utilizes a thermal-magnetic-mechanical converting consists of two cross-jointed Al arms, two Gd sheets, two NdFeB hard magnets, two thermoelectric generators (TEGs), and a ball bearing set. When comparing conventional thermomagnetic grippers, our thermomagnetic tweezer can grip either ferromagnetic or non-ferromagnetic objects and avoid producing temperature-influence to the gripped objects. Experimental results show that we can control TEGs to generate a temperature difference to operate the tweezer to grip small ferromagnetic objects (such as NdFeB hard magnet) and other non-ferromagnetic objects (such as PMMA bulk). The maximum gripping force produced by the tweezer operated by applying the DC current of 1.3 A with the voltage of 0.85 V is 0.59 newton. The corresponding gripping and releasing duration is 7.9 seconds and 8.1 seconds, respectively. According to these results, our tweezer would produce more practical objects-gripping applications.