TY - JOUR
T1 - Micro-stereolithography of three-dimensional polymeric springs for vibration energy harvesting
AU - Baker, Evan
AU - Reissman, Tim
AU - Zhou, Fan
AU - Wang, Chen
AU - Lynch, Kevin
AU - Sun, Cheng
PY - 2012
Y1 - 2012
N2 - The inefficiency in converting low frequency vibration (6~240 Hz) to electrical energy remains a key issue for miniaturized vibration energy harvesting devices. To address this subject, this paper reports on the novel, three-dimensional micro-fabrication of spring elements within such devices, in order to achieve resonances and maximum energy conversion within these common frequencies. The process, known as projection microstereolithography, is exploited to fabricate polymer-based springs direct from computer-aided designs using digital masks and ultraviolet-curable resins. Using this process, a micro-spring structure is fabricated consisting of a two-by-two array of three-dimensional, constant-pitch helical coils made from 1,6-hexanediol diacrylate. Integrating the spring structure into an electromagnetic device, with a magnetic load mass of 1.236 grams, the resonance is measured at 61 Hz, which is within 2% of the theoretical model. The device provides a maximum normalized power output of 9.14 μW/G ( G = 9.81 ms−2) and an open circuit normalized voltage output of 621 mV/G. To the best of the authors knowledge, notable features of this work include the lowest Young’s modulus (530 MPa), density (1.011 g/cm3), and “largest feature size” (3.4 mm) for a spring element in a vibration energy harvesting device with sub-100 Hz resonance.
AB - The inefficiency in converting low frequency vibration (6~240 Hz) to electrical energy remains a key issue for miniaturized vibration energy harvesting devices. To address this subject, this paper reports on the novel, three-dimensional micro-fabrication of spring elements within such devices, in order to achieve resonances and maximum energy conversion within these common frequencies. The process, known as projection microstereolithography, is exploited to fabricate polymer-based springs direct from computer-aided designs using digital masks and ultraviolet-curable resins. Using this process, a micro-spring structure is fabricated consisting of a two-by-two array of three-dimensional, constant-pitch helical coils made from 1,6-hexanediol diacrylate. Integrating the spring structure into an electromagnetic device, with a magnetic load mass of 1.236 grams, the resonance is measured at 61 Hz, which is within 2% of the theoretical model. The device provides a maximum normalized power output of 9.14 μW/G ( G = 9.81 ms−2) and an open circuit normalized voltage output of 621 mV/G. To the best of the authors knowledge, notable features of this work include the lowest Young’s modulus (530 MPa), density (1.011 g/cm3), and “largest feature size” (3.4 mm) for a spring element in a vibration energy harvesting device with sub-100 Hz resonance.
M3 - Article
JO - Smart Materials Research
JF - Smart Materials Research
ER -