Diamagnetically levitated Milli-robots for heterogeneous 3D assembly

In this article, we demonstrate diamagnetically levitated milli-robots performing 3D heterogeneous micro-assembly of silicon micro-machined parts and polymer microspheres. Diamagnetically levitated milli-robots, in conjunction with controlled magnetic fields from printed circuit boards, can enable very precise, low cost, high density, and an easily scalable approach to massively parallel micro-assembly. By using an eddy-current dampening layer to suppress ambient external forces, we measured an open-loop in-plane equilibrium motion repeatability of 28.6 nm rms over cm’s of travel and a total vertical range of 50–70 μm. To perform micro-assembly, light-weight end effectors and force compatible micro-processes (i.e. micro-grasping and liquid handling) were integrated with the diamagnetic levitated milli-robots. Various tele-operated micro-assembly tasks were demonstrated such as joining polymer micro-spheres, interlocking silicon micro-parts, and printing electrical interconnects. Multiple specialized milli-robots, each taking up only 31 mm2, are used to perform each individual micro-task. In the future, by developing more sophisticated milli-robots and operating many more of these milli-robots in parallel, a dense, automated, rapid milli-robot assembly may be possible.