We began developing flexonic components with a rapid-prototyping system known as Fused Deposition Modeling (Stratasys, Inc.). With FDM, fully functional passive devices can be made from either rigid ABS plastic or flexible elastomer. Complex parts with regions of overhang and irregular surfaces can be easily built using a system that integrates build material and sacrificial support material. We have built several flexure-based designs using FDM. These devices are shown in subsequent figures as a demonstration of flexonic components. However, FDM has disadvantages when applied to the problem of fabricating a broad range of flexonic devices, including dielectric elastomer actuators. Few materials are available, resolution is relatively poor, part strength and properties are influenced by build orientation, and electronic components are not realizable. An all inkjet printing process will overcome these manufacturing obstacles.

One of the requirements for most mechanical designs is some form of rotary joint. We have printed various joints and have identified several designs for possible inclusion within flexonic mechanisms. more

Higher-order mechanisms
While flexonics can provide a base set of simple mechanical joints, it also encourages highly complex single-piece devices. These include mechanisms for power transmission, motion generation, and specilized functions
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Structural volumes
Mechatronic devices need passive structural volumes to support and connect moving components. In traditional designs, these bulk volumes take on the form of three-dimensional solid links or, at best, two-dimensional structures like honeycombs. High strength-to-weight performance can be achieved through one-dimensional trusses, but this is usually only feasible on a large scale or through very expensive investment casting. However, with flexonic manufacturing, we can print intricate geometry to create lightweight truss and lattice volumes.

We believe dielectric elastomer actuation is the most promising technology for producing flexonic motion. When a large electric field is applied across a thin dielectric elastomer film, the resultant stress (Maxwell stress) squeezes the film in thickness and expands it in area. This principle can be applied to create light weight, highly energetic actuators. One method of creating a planar actuator is to sandwich a dielectric elastomer film between two supportive frames.

two stage thin-strip rotary joint

mechanism which transmits rotary motion of bottom joint to successive joints

diamond lattice structural volume

prototype frame for dielectic elastomer actuators
  last updated 08.02.03