FDM Printing: a Fabrication Method for Fluidic Soft Circuits? (2312.01131v1)

Abstract: Existing fluidic soft logic gates for the control of soft robots either rely on extensive manual fabrication processes or expensive printing techniques. In our work, we explore Fused Deposition Modeling for creating fully 3D printed fluidic logic gates. We print a soft bistable valve from thermoplastic polyurethane using a desktop FDM printer. We introduce a new printing nozzle for extruding tubing. Our fabrication strategy reduces the production time of soft bistable valves from 27 hours with replica molding to 3 hours with a FDM printer. Our rapid and cost-effective fabrication process for fluidic logic gates seeks to democratize fluidic circuitry for the control of soft robots.

• The paper demonstrates that FDM printing reduces production time from 27 hours to three hours in fabricating soft bistable valves.
• It introduces a novel nozzle design for direct extrusion of tubular structures, optimizing the fabrication of XOR gates and D-latches.
• The work broadens soft robotics applications by democratizing fluidic circuit production using inexpensive, readily available materials.

Introduction

Soft robots, constructed from pliable materials, provide unique advantages over traditional robots, including adaptability, safer interaction with humans, and resilience to impacts. Nonetheless, soft robots often require rigid electronic components for control, counteracting their inherent compliance benefits. To address this, researchers have turned towards soft bistable valves and fluidic soft logic gates to control pneumatic actuators in soft robots. Bistable valves facilitate complex functionalities like pressure switching and can be assembled into various logic gate configurations for advanced fluidic circuits. However, current fabrication methods for these valves are either labor-intensive or necessitate costly printing machinery, posing a barrier to rapid prototyping and academic dissemination.

Advances in 3D Printing for Fluidic Components

In an effort to democratize the production and prototyping of soft logic gates and circuits, the integration of Fused Deposition Modeling (FDM) printing technology has been investigated. Benefiting from its affordability and use of commercially available materials, a soft bistable valve was successfully 3D printed using a desktop FDM printer. A significant reduction in production time from 27 hours via traditional replica molding to three hours with FDM printing has been achieved. Furthermore, a novel printing nozzle was developed, enabling the direct extrusion of tubular structures, thus furthering the quality and possibilities for fluidic circuitry.

Optimized Logic Circuits

With the development of FDM printable soft bistable valves, optimization of fluidic circuits was pursued, specifically targeting XOR gates and D-latches which are critical for computational logic and storage. By innovating the design of a soft bistable valve, studies have reduced the complexity of an XOR gate from requiring five logic elements to only three. Moreover, the iconic D-latch—a latch that synchronizes and stores digital data—has been reconfigured using an INHIBIT gate together with 3D-printed bistable valves, resulting in a dramatic reduction in component count.

Implications and Future Work

The work has far-reaching implications for the field of soft robotics, particularly in simplifying the fabrication of fluidic soft circuits and logic elements. By producing functional fluidic soft circuits using low-cost FDM printers and materials like thermoplastic polyurethane, researchers encourage broader adoption within academic and educational settings. Printable soft bistable valves not only facilitate rapid prototyping but may also lead to creative and diverse applications in soft robotics. Future prospects include commercial availability of the custom nozzle for tube extrusion and further exploring the material and design parameters to enhance the performance of 3D-printed fluidic components.