Survey of sticking effects for micro parts handling

When parts to be handled are less than one millimeter in size, adhesive forces between gripper and object can be significant compared to gravitational forces. These adhesive forces arise primarily from surface tension, Van der Waals, and electrostatic attractions and can be a fundamental limitation to part handling in a gas environment. While it is possible to fabricate miniature versions of conventional robot grippers, for example from polysilicon, it appears that it will be difficult to overcome adhesion effects for the smallest parts. Thus, manipulation of parts on the order of 10 micron or smaller may best be done in a fluid medium using techniques such as laser trapping, or dielectrophoresis.