Microgripper: Design, finite element analysis and laser microfabrication

This research is focused on new and innovative design, finite element analysis, precision laser microfabrication, and performance evaluation of a microgripper. The design of the microgripper with overall dimension of 1.4(W)x2.8(L)mm is based on a pair of cascaded structures oriented in a face-to-face direction, to act as microtweezers. Each cascaded structure is formed by connecting several basic actuation units in series. Each actuation unit consists of a constrainer and two semi-circular-shaped actuation beams. The actuation principle is based on the electrothermal effect. On application of electrical potential, the output displacement and the force are generated from the summation of all basic actuation units in these cascaded structures. Finite element analysis (FEA) is applied to simulate dynamic performance of the microgripper and to choose proper operational voltage parameters. Thin nickel foil of a thickness of 12.5 micrometers was used in the laser microfabrication of these prototypes. Dynamic performance of the prototype device was evaluated within 0-1.9 voltage range. The maximum tweezing displacements of up to 30 micrometers were recorded for nickel microgripper prototype. Larger displacements are feasible through the optimization of design parameters.