Magnetic field-assisted manufacturing of groove-structured flexible actuators with enhanced performance

Magnetic flexible actuators with hard -magnetic particles (NdFeB) as inlays have attracted widespread attention due to their small size, wireless control capability, and diverse transformation modes. The manufacturing method of these actuators plays a crucial role in their functionality. Here we propose a magnetic field -assisted manufacturing method based on vat photopolymerization (VPP) to produce hard -magnetic flexible actuators with 3D architecture in both geometry structure and magnetization arrangements. The assisting magnetic field enables alignment of hard magnetic particles during manufacturing process, thus obtaining a magnetization arrangement. The VPP method offers the ability to manufacture fine structures and selective curing but has a limitation on the magnetic particle content. To deal with the lack of driving force due to the low available content of magnetic particles, we construct groove structure to enhance the actuators' deformation, which is confirmed by both theoretical and experimental analyses. Flexible actuators with a low magnetic particle content (10 wt%) can be fabricated and fulfill intended functionality. We demonstrate the effectiveness of our method by manufacturing multi -arm grippers, showcasing their transportation capabilities. Moreover, we construct a 2-DOF joint for a crawling robot, significantly improving its motion performance and increasing the average step length to 6.8 times. Finally, we design and manufacture a magnetic diaphragm with complex structure and 3D magnetization arrangements, which is applied to a micro pump, demonstrating its pumping process with a rate of about 3.6 mL/min. These results highlight the potential of the proposed method in designing complex structures and magnetization arrangements of flexible actuators, expanding their functional boundaries.