High Speed and Low Weight Micro Actuators for High Precision Assembly Applications - Micro Actuators with the Micro Harmonic Drive®

The trend to miniaturization cannot be overseen. The use of very small electronic and electro-optical components in a variety of consumer and investment goods is leading to an increasing demand for small-scale servo actuators for micro assembly applications in production equipment. The previous generation of micro gears and micro actuators was not suited to this type of application, because of unacceptable accuracy. The Micro Harmonic Drive gear was introduced into the market in 2001 as the world’s smallest backlash-free micro gear. It is manufactured using a modified LIGA process, called Direct-LIG. This allows the cost-effective production of extremely precise metallic gear components. In the meantime this gear has been implemented in a range of miniaturized servo actuators, which provide zero backlash, excellent repeatability and long operating life. In addition to the above-mentioned advantages this innovative product also features a central hollow shaft. This allows the design engineer to pass an optical fiber, a laser beam or media such as fluids, compressed air or vacuum along the central axis of the servo actuator. This greatly simplifies the design of machines for micro assembly applications in the semi conductor, consumer goods, medical and optical fields. In this paper we will describe the development history, key features and applications of this innovative drive solution.