Thermal Characterization of New 3D-Printed Bendable, Coplanar Capacitive Sensors

Ragolia, Mattia Alessandro; Lanzolla, Anna Maria Lucia; Percoco, Gianluca; Stano, Gianni; Nisio, Attilio Di

doi:10.3390/s21196324

Cited by 18 publications

(8 citation statements)

References 29 publications

(30 reference statements)

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“…Some examples of bending pneumatic actuators equipped with strain sensors (fabricated using a dual extruder machine) are provided in [9][10][11]. Several results have been achieved in this field such as: (i) a way to improve the object grasping capability, (ii) the possibility to fabricate embedded air connectors [12] and (iii) the possibility to obtain helicoidal motion [13]. Shape memory polymers actuator is based on phase change of the materials such that the change of Young's modulus when the switching temperature (Ts) is reached resulting in a change of material softness.…”

Section: Introductionmentioning

confidence: 99%

One-shot additive manufacturing of robotic finger with embedded sensing and actuation

Stano

Ovy

Edwards

et al. 2022

Int J Adv Manuf Technol

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A main challenge in the additive manufacturing (AM) field is the possibility to create structures with embedded actuators and sensors: addressing this requirement would lead to a reduction of manual assembly tasks and product cost, pushing AM technologies into a new dimension for the fabrication of assembly-free smart objects. The main novelty of the present paper is the one shot fabrication of a 3D printed soft finger with an embedded shape memory alloy (SMA) actuator and two different 3D printed sensors (strain gauge and capacitive force sensor). 3D printed structures, fabricated with the proposed approach, can be immediately activated after their removal from the build plate, providing real-time feedback because of the embedded sensing units. Three different materials from two nozzles were extruded to fabricate the passive elements and sensing units of the proposed bioinspired robotic finger and a custom-made Cartesian pick and place robot (CPPR) was employed to integrate the SMA spring actuator into the 3D printed robotic finger during the fabrication processes. Another novelty of the present paper is the direct integration of SMA actuators during the 3D printing process. The low melting thermoplastic polycaprolactone (PCL) was extruded: its printing temperature of 70 °C is lower than the SMA austenitic start temperature, preventing the SMA activation during the manufacturing process. Two different sensors based on the piezoresistive principle and capacitive principle were studied, 3D printed and characterized, showing respectively a sensitivity ratio of change in resistance to finger bending angle to be 674.8 $$\frac{\Omega }{^\circ \mathrm{Angle}}$$ Ω ∘ Angle and a capacitance to force ratio of $$0.53 \frac{\mathrm{pF}}{\mathrm{N}}$$ 0.53 pF N . The proposed manufacturing approach paves the way for significant advancement of AM technologies in the field of smart structures with embedded actuators to provide real-time feedback, offering several advantages, especially in the soft robotics domain.

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Section: Introductionmentioning

confidence: 99%

One-shot additive manufacturing of robotic finger with embedded sensing and actuation

Stano

Ovy

Edwards

et al. 2022

Int J Adv Manuf Technol

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“…Moreover, the temperature was measured during the performed tests (since it affects sensor capacitance), and it was assessed to be stable (about 20 °C). A detailed analysis of the effect of temperature on the capacitance of the proposed capacitive sensors was carried out in [44], highlighting a nonlinear dependence of capacitance on temperature and obtaining a model to compensate for its effect. Using the testing setup and protocol detailed in Sect.…”

Section: Resultsmentioning

confidence: 99%

Additive manufacturing for capacitive liquid level sensors

Stano

Nisio

Lanzolla

et al. 2022

Int J Adv Manuf Technol

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A new manufacturing wave concerning the Additive Manufacturing of sensors is spreading: several benefits, such as cost, time, and manual task reduction, can be achieved. The aim of the present research is the one-shot Additive Manufacturing of a low-cost capacitive sensor for liquid level sensing. The Material extrusion (MeX) technology was used to fabricate the proposed sensors (composed of a flexible substrate, two conductive electrodes, and a top flexible coverage), and a Design for Additive Manufacturing (DfAM) approach in conjunction with the 3D printing force analysis was performed. Very thin conductive tracks (0.5 mm) were manufactured to obtain a sensor having a final capacitance value of 125 pF, readable by common laboratory instrumentation. The sensor has been tested for the liquid level sensing using two different liquids, i.e., sunflower oil and distilled water, exhibiting very good sensitivity of 0.078 $$\frac{pF}{mm}$$ pF mm and 0.79 $$\frac{pF}{mm}$$ pF mm , respectively, with high repeatability, thus obtaining sensing performances comparable with that of more expensive sensors found in literature. Moreover, the proposed sensor showed high linearity (R2 ≥ 0.997), which resulted in a maximum propagated level error of 1.4 mm. The present research proves that the inexpensive MeX technology can be successfully employed for the fabrication of high-performance capacitive sensors: the sensor manufacturing cost (related to raw materials) is 0.38 €, and no manual assembly tasks were performed. This study lays the foundation for the one-shot fabrication of smart structures with capacitive sensors on board, saving manufacturing time and cost.

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“…Based on 3D-printed hemisphere microstructure arrays on a PDMS substrate, Shao realized a pressure sensor with a 0.00354 S/kPa sensitivity at 0–22 kPa . Although great progress has been made in the use of microstructures to realize high-performance pressure sensors, the manufacturing processes for microstructures such as particle templating, , 3D printing, , and lithography , are complex, time-consuming, or uneconomical, which limits the manufacture of microstructure-based flexible sensors at a large scale. Microwave irradiation is a convenient process for producing porous materials, which has recently been used to prepare a flexible pressure sensor with porous structure .…”

Section: Introductionmentioning

confidence: 99%

High-Performance Porous PDMS-Based Piezoresistive Sensor Prepared by a Modified Microwave Irradiation Process

Zhao

Xiao

et al. 2022

ACS Appl. Electron. Mater.

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The flexible pressure sensor based on a porous structure has excellent sensing performance. It is critical to develop a large-scale and lowcost manufacturing method for realizing high-performance flexible sensors with porous structures. Herein, a porous polydimethylsiloxane (PDMS) was prepared by a modified microwave irradiation process, and an ultrahigh sensitive flexible piezoresistive sensor with wide sensing range was obtained by coating carbon nanotubes (CNTs)/graphene on the porous PDMS surface. Due to the uniform macroporous structure in PDMS and the synergistic conductive effect of graphene and CNTs, the sensitivity of the flexible sensor is up to 300.31 kPa −1 in 0−50 kPa and 52.51 kPa −1 in 50−200 kPa. Moreover, the flexible device has good reversibility, rapid response speed, good stability, and a certain anti-electromagnetic interference ability. The application in the monitoring of physiological signals demonstrates that the porous PDMS-based sensor prepared by the convenient and environmental microwave irradiation process has remarkable ability in monitoring human health. In addition, the modified microwave irradiation method also provides a way for the preparation of porous materials for other applications such as electromagnetic shielding materials.

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Thermal Characterization of New 3D-Printed Bendable, Coplanar Capacitive Sensors

Cited by 18 publications

References 29 publications

One-shot additive manufacturing of robotic finger with embedded sensing and actuation

One-shot additive manufacturing of robotic finger with embedded sensing and actuation

Additive manufacturing for capacitive liquid level sensors

High-Performance Porous PDMS-Based Piezoresistive Sensor Prepared by a Modified Microwave Irradiation Process

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