A micro cycloid-gear system fabricated by multi-exposure LIGA technique

 In this paper, a prototype of 2 mm-diameter micro-cycloid gear system fabricated by the multi-exposure LIGA technique is presented. The gear system is composed of a casing and three vertically stacked disks and gears. Each part consists of three different levels. The first level, 40 μm high, was fabricated by UV-lithography, and the second as well as the third level, 195 μm and 250 μm high respectively, were processed by aligned deep X-ray lithography (DXL). The alignment error between two DXL-processed layers has been measured to be within ±5 μm range. As a result of the height control process, the deviation of structural height has been maintained within ±3 μm range for the UV-lithography-processed structures, and ±10 μm for the DXL-processed structures. Preliminary tests of gear assembly have been implemented with 125 μm-diameter commercially available glass fiber, and the further efforts are being carried out.