4D Printing Inflatable Silicone Structures

Abstract

This article details steps in creating low-power artificial muscles using 3D printing. It describes a manufacturing system that can be used to fabricate seamless tubular dielectric elastomer actuators (DEA), for eventual use in biorobotic devices. The focus is on producing passive elastomeric components of DEA and the dimensional changes that occur after printing is complete. A four-axis printing system is described, capable of spray depositing multilayer tubular silicone membranes onto an air-permeable mandrel. Mechanical strain was imparted in the membranes by means of inflation. A laser measurement system was constructed to act as a 3D scanner, which measured the shape of the inflated ''balloon.'' The surface shape was reconstructed in software using the parametric modeling tool Grasshopper. Seamless auxetic tessellations were calculated across the entire surface, and then converted to CNC GCode. These toolpaths were then physically extruded over the surface of the balloon, stacked five layers high. When the extruded silicone structure was completely cured, the pneumatic strain was released, allowing the structure to collapse evenly. The compression in the printed structure was balanced by the tension in the stretched membranes, thus producing a minimum energy structure.

Soft Manipulators and Grippers: A Review

“…Using this method, dielectric elastomer actuators can be developed (Araromi et al, 2011). Additionally, this method can be incorporated into a 4D system in which silicone can be deposited to form a multilayered tubular system by forming layers onto of an air-permeable shaft, and this allows the development of inflatable balloon-like structures (Coulter and Ianakiev, 2015).…”

Fabricate 2017

“…In the case of tensile and membrane structures, additive manufacturing offers the possibility of developing composite surfaces with programmable material behaviours while also exploring novel performative geometries for net structures (Coulter & Ianakiev, 2015).…”

Production Techniques for 3D Printed Inflatable Elastomer Structures: Part II—Four-Axis Direct Ink Writing on Irregular Double-Curved and Inflatable Surfaces

“…This series of papers expands and fully explains the techniques exposed in Ref. 6 There are numerous applications for such techniques, including the creation of 3D printed medical devices such as 3D printed collapsible stents 8 mounted directly on removable inflatable substrates, the fabrication of Dielectric Elastomer Actuators, 9 or, more specifically, Dielectric Elastomer Minimum Energy Structures, 10 along with Pneumatic Artificial Muscles 11 and other soft robotic applications. The techniques also have applications beyond inflatable structures-any non-uniform tubular substrate can be printed on, and this has great potential in bio-fabrication and bio-plotting applications, 12 along with printed electronics in robotics and structural monitoring.…”

“…5 Recent publications describe deposition systems that can measure the shape and size of an unknown curved substrate and then immediately print on it in a repeatable accurate manner. 6,7 This article fully describes a novel method to scan and extrude on double curved surfaces, focusing on a substrate that is a stretched and inflated balloon-like membrane (described in Part 1 of this article), mounted on a rotating fourth axis within the printer gantry. This series of papers expands and fully explains the techniques exposed in Ref.…”