Design and fabrication of an electrothermal MEMS micro-actuator with 3D printing technology

Abstract

This study presents the design and fabrication results of an electrothermal micro-electro-mechanical system (MEMS) actuator. Unlike traditional one-directional U-shaped actuators, this bi-directional electrothermal (BET) micro-actuator can produce displacements in two directions as a single device. The BET micro-actuator was fabricated using two-photon polymerization (2PP) and digital light processing (DLP) methods, which are 3D printing techniques. These methods have been compared to see the success of BET micro-actuator fabrication. The compound of these methods and the essential coefficients through the 3D printing operation were applied. Evaluation experiments have demonstrated that in both methods, the 3D printer can print materials smaller than 95.7 μm size features. Though the same design was used for the 2PP and DLP methods, the supporting structures were not produced with the 2PP. The BET micro-actuator was manufactured by removing the supports from the original design in the 2PP. The number of supports, the diameter, and height on the arms of the micro-actuator is 18, 4 μm, and 6 μm, respectively. Although 4 μm diameter supports could be produced with the DLP, it was not possible to produce them with 3D printing device based on 2PP. Besides, the DLP was found to be better than the 2PP for the manufacturing of asymmetrical support structures. The fabrication process has been carried out successfully by two methods. When the fabrication success is compared, the surface quality and fabrication speed of the micro-actuator fabricated with DLP is better than the 2PP. Presented results show the efficiency of the 3D printing technology and the simplicity of fabrication of the micro-actuator via 2PP and DLP. An experimental study was carried out to characterize the relationship between displacement and input voltage for the micro-actuator. Experimental results show that the displacement range of the micro-actuator is 8 μm with DLP, while 6 μm with 2PP.