Multi-Material 3D Printed Bendable Smart Sensing Structures

Abstract

This paper presents a novel additive manufacturing method to obtain bendable smart sensing structures having printed strain sensors and interconnects to gain access to embedded electronic components. The presented smart structure is obtained by simultaneous printing of functional materials along with conventional polymer-based 3D printing materials. To this end, a low-cost open-source 3D printer was augmented with a silver palladium metallic paste extruder. The strain sensors in the presented 3D printed smart structure are particularly useful for wearable motion sensing applications such as knee joint motion analysis. The printed interconnects allow for electrical connection with the Light Emitting Diodes (LEDs) embedded within the 3D printed structure. With electronic components embedded in the flexible 3D printed structure, this work also demonstrates a novel method for soft packaging of electronic and sensing components. The electrical tests conducted on the smart structure show excellent electrical continuity. The 3D printed strain sensors, tested in static and dynamic bending conditions, showed a linear response of resistance. Under no strain, the resistance of the sensor was measured to be 0.9671 Ω (resistivity of 9.671×10-6 Ω.m) and during testing it exhibited a gauge factor of 1. Multi-material additive manufacturing demonstrated in this paper opens a new direction for fabrication of complex 3D structures with embedded sensors and electronics and offers significant advantages for rapid prototyping and packaging.

3D Printed Interconnects on Bendable Substrates for 3D Circuits

“…However, it is still at its infancy and the examples produced by groups so far have generally focussed on planar, non-moving circuitry. This paper proposes to extend the functionality of 3D printed devices to include multi-material bendable structures [13]. With regards to the materials used, several filaments [14]- [17] and inks [18]- [20] have been developed to drive this fabrication method.…”

“…This paper will build on that knowledge and suggest new solutions in this regard. In this direction, our recent work [13] demonstrated a 3D printed smart bendable structure for sensing applications. However, the present work illustrates an advancement towards the development of interconnects on more bendable substrates using a different ink and conductive filament.…”

3D Printed Robotic Hand with Embedded Touch Sensors

“…The developed sensorised fingertips are robust, show stable response and are affordable. Compared to other works where embedded off-the-shelf sensors have been reported [14,[18][19][20][21], the fingertip presented here have intrinsic sensors realised by fully 3D printing. The presented facile approach has the potential to be scaled up to large-area manufacturing.…”

“…In recent years, the automotive, aeronautic and medical industries are using such system as one of their manufacturing processes [22][23][24][25][26]. The field is now exploring how to extend the capabilities of FDM printers utilizing flexible/bendable materials, composited filaments and custom-made Direct Ink Writing (DIW) extruders, which are capable of printing conductive lines to enable new designs, ideas and products [14,19,[27][28][29]. Several devices have been developed benefiting from such advantages to overcome challenges inherited from other fabrication processes.…”

Development of Soft sEMG Sensing Structures Using 3D-Printing Technologies

“…Direct conductive 3D-printing has been demonstrated with the use direct-ink writing using silver particle infused inks or elastomers [ 33 , 34 , 35 , 36 ]. Fused deposition modeling (FDM) and stereo lithography (SLA) are commercially available printing technologies that allow direct conductive 3D-printing.…”