Design, fabrication, and testing of a three-dimensional, plastically-deformed, monolithic compliant HexFlex Nanomanipulator

Abstract

An experimental study was performed to investigate the possibility of incorporating plastic deformation into a precision compliant mechanism design. The particular application of a compliant HexFlex Nanomanipulator was chosen as a mechanism to extend plastically into three dimensions. The mechanism was built to competitive Nanomanipulator functional requirements employing non-precision methods of fabrication, such as the abrasive waterjet. New tooling was created in order to selectively define which parts of the delicate mechanism to plastically deform. Once formed, the mechanism was tested to determine if the plastic deformation process in the forming of the mechanism has undesirable effects on its performance as a Nanomanipulator. An input/output correlation test was performed in order to determine the correspondence of the physical model to a finite-element analysis of the same. The out-of-plane, time variable position drift (both immediately after forming as well as a week after forming) was measured to quantify the effects of creep and stress relaxation on Nanomanipulator position. The out-of-plane creep under near-yield loading conditions was also measured. For the work volume of 75x75x75 [micro]m³, the experimental results corresponded to within 8%, on average, to the predicted values. Over the course of the 24 hours following the plastic deformation, the output stage drifted 6 [micro]m due to stress relaxation, compared with a daily fluctuation due to thermal expansion and contraction of amplitude 1 [micro]m. Over the course of 24 hours of loading the mechanism near its elastic yield point, the mechanism crept 2 [micro]m.