A multi-material milli-robot prototyping process

Photo-patternable adhesives and silicones are introduced for use in centimeter-scale robotics. Traditional approaches to making robots at this size scale require the use of expensive start-up equipment and/or precise machining, and generally yield fragile and costly robots in small numbers. The multi-material milli-robot prototyping process uses Loctite® polymer products and photolithography to rapidly fabricate robust, inexpensive, and compliant robots only centimeters in size. In this paper, the process flow is described and characterized with minimum feature sizes of 0.25 mm in polymer layers 0.18 mm thick. Both commercial and ink-jet printed masks are used for the photolithography steps. Finally, a functional inchworm robot and a small gripper have been designed and demonstrated with Nitinol shape memory alloy (SMA) used for actuation. The gripper is 1.2 g and costs $3.21 in small numbers while the inchworm robot is 7.4 g and costs $7.76 in small numbers. Building a functional robot from a computer design takes less than 1 hour.