Manipulation of micro sphere move using liquid bridge forces

A method is presented to manipulate microspheres using liquid bridge forces to overcome the influence of adhesion during micro-electro-mechanical system assembly. The liquid bridge force between the microsphere and the manipulation arm is utilized to grasp the microsphere, with the liquid bridge force between the microsphere and the target plane then utilized to release it. The various forces acting on the microsphere were analyzed to show that gravity can be neglected. The microsphere can be easily grasped because the adhesive force between a dry sphere and a rough surface is very small. The microsphere is released because of the small tip radii of the manipulation arm and the small interface energy between the liquid and solid tip. The method has been used to successfully assemble a micro rolling guide.