Microstereophotolithography and shape memory alloy for the fabrication of miniaturized actuators

A new microassembly technique has been developed to combine polymer micro-objects fabricated by stereophotolithography with shape memory alloy (SMA) wires. This technique is based on a local laser aided polymerization allowing SMA wires to be associated with polymer structures. Since stereophotolithography allows the fabrication of real three-dimensional objects, different mechanical structures have been designed and manufactured to develop miniaturized mechanical devices (in the centimetre range) with multiple degrees of freedom actuated by SMA wires (diameter 120 mu m). The actuation principle has been successfully tested. Experimental measurement procedure and results are presented and discussed. Further developments and improvements of the actuators are proposed. (C) 1997 Elsevier Science S.A.