Design Of Rotatory SMA Actuators For Small Machine Tools

Shape memory alloys (SMA) are thermally activated smart materials. They have the ability to change into a previously imprinted shape through thermal or electrical activation. Due to this thermal effect, SMA are suitable as actuators in mechatronic systems. In a current research project, the Chair of Production Systems is examining the use of multiple modular and standardized SMA actuators in the feed axis of a small machine tool. In the future, these machines shall be used to manufacture small work pieces with high precision. Therefore, the actuators must be qualified to handle movements in the micrometer range. Following the initial development of linear feed modules for a 3-axes machine, additional rotatory modules driven by SMA actuators are needed. In the scope of this paper, the technical requirements and the steps of the design process are detailed. The overall goal is to construct a modular machine tool, consisting of different linear and rotatory SMA axis, which can be configured according to the manufacturing task at hand. Thereby, machines with degrees of freedom ranging from 1 to 5 axes are feasible.