Name: fabrication of soft pneumatic network actuators with oblique chambers
Uploaded: 2018-08-17T14:30:00.000+00:00
Duration: 7 min 9 s
Description: Watch this Scientific Journal Video about Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers at JoVE.com

This work was supported by the National Natural Science Foundation of China under Grant 51622506 and the Science and Technology Commission of Shanghai Municipality under Grant 16JC1401000.

NOTE: The protocol provides the fabrication procedures of a soft pneumatic network actuator. Before the fabrication procedure, a set of molds and several actuator-tubing connectors, which are designed with computer-aided design (CAD) software must be 3-D-printed in advance. The molds are shown in Figure 1B.
1. Silicone Elastomer Preparation
<ol>
	<li>Weigh 5 g of silicone elastomer part B and 45 g of part A [9:1 (A:B) parts by weight] in the same mixing container (Figure 2A). Use a syringe to make sure the proportions of each part are accurate. 
	NOTE: The mixing ratio varies for different silicone elastomers. The proportion of each part should be adjusted when another silicone elastomer is adopted.</li>
	<li>Mix the silicone elastomer well with the planetary centrifugal mixer. 
	NOTE: The silicone elastomer could be stored at a low temperature to extend its processing time.</li>
</ol>
2. Chamber Part Fabrication
<ol>
	<li>Spray the mold release agent for silicone elastomer products evenly on the surfaces of the mold part A and part B.</li>
	<li>Assemble part A and part B of the mold for the fabrication of a chamber. Hold both ends of the mold with clips to prevent the leakage of silicone elastomer.</li>
	<li>Take 5 mL of silicone elastomer with a syringe and inject it slowly into the hole of the mold for fabricating the connection end (the cylindrical structure at one end of the actuator for connecting the tubing). Then, fill the whole mold with the silicone elastomer (Figure 2B). 
	NOTE: Keep a low flow rate and move back and forth slowly, to let the silicone elastomer enter the tiny structures of the mold.</li>
	<li>Pierce the bubbles that form on the surface with the tip of a needle until there are no more bubbles visible (Figure 2C).</li>
	<li>Scrape off any excess silicone elastomer with a blade along the upper surface of the mold.</li>
	<li>Place the mold in the oven at 70 &#176;C until the silicone elastomer is cured.</li>
	<li>Use a syringe to inject silicone elastomer into the bubbles and holes which appear on the surface of the actuator.</li>
	<li>Scrape off any excess silicone elastomer on the surface.</li>
	<li>Place the mold in the oven at 70 &#176;C until the silicone elastomer is cured.</li>
</ol>
3. Base Part Fabrication
<ol>
	<li>Spray the mold release agent for silicone elastomer products evenly on the surface of the mold part C.</li>
	<li>Pour the silicone elastomer into part C of the mold.</li>
	<li>Pierce the bubbles that form on the surface with the tip of a needle until there are no more bubbles visible.</li>
	<li>Scrape off any excess silicone elastomer with a blade along the upper surface of the mold.</li>
	<li>Place the mold in the oven at 70 &#176;C until the silicone elastomer is cured.</li>
</ol>
4. Actuator Assembly
<ol>
	<li>Evenly pour a layer of silicone elastomer, 1 mm in thickness, on one face of the base part.</li>
	<li>Place the chamber part on the base part. Use a syringe to inject the silicone elastomer into the space between the chamber part and the base part (Figure 2D).</li>
	<li>Place the actuator in the oven at 70 &#176;C until the silicone elastomer is cured.</li>
</ol>
5. Tubing Connection
<ol>
	<li>Tap the 3-D-printed actuator-tubing connector to accept the screw of a male stud push-in fit pneumatic fitting.</li>
	<li>Use a needle to pierce the connection end of the actuator along the centerline of the cylinder. Increase the diameter of the hole with a steel rod, to about 2 mm.</li>
	<li>Screw the actuator-tubing connector into the actuator (Figure 2E).</li>
	<li>Push a section of tubing into the male stud push-in fit pneumatic fitting.</li>
</ol>
6. Leak Check and Repair
<ol>
	<li>Connect the actuator to an air source.</li>
	<li>Place the whole actuator in the water and pressurize the actuator (Figure 2F). Observe whether bubbles are formed due to a leak.</li>
	<li>Use a syringe to inject the silicone elastomer into leak points. Place the actuator in the oven at 70 &#176;C until the silicone elastomer is cured.</li>
	<li>Repeat steps 6.1 - 6.3 if needed.</li>
</ol>

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The authors have nothing to disclose.

The paper presents a method protocol to guide the fabrication of soft pneumatic network actuators with oblique chambers. Following the protocol, one actuator can be fabricated independently within 3 h. The key steps in the protocol can be summarized as follows. (i) The silicone elastomer is prepared in proportion and mixed well. (ii) The silicone elastomer is poured into the mold for the fabrication of the chamber part and the base part. (iii) The bubbles on the exposed surface are pierced and any excess silicone elastom...

Soft pneumatic actuators (SPAs) are soft devices that can be actuated by the simple input of air pressure1,2. They can be fabricated with diverse materials, such as silicone elastomers3, fabrics4, shape-memory polymers5, and dielectric elastomers6. Researchers have benefited from their nature of compliance, dexterous motions, and simple fabrication methods7, such that SPAs have become one of the most promising devices for soft robotics applications8,9. SPAs can realize various sophisticated motions, such as creeping10, rotation11, and rolling12 based on various types of deformation, including extending, expanding, bending, and twisting13,14. To be able to make different types of motions, SPAs are designed in different structures, such as a linear body with parallel channels15, a monolithic chamber with fiber-reinforcements16, and networks of repeated sub-chambers17. Among them, the SPAs with networks of repeated sub-chambers, the soft pneumatic network actuators, are widely employed because they can generate large deformations under a relatively low input pressure. However, in most of the previous designs, this type of actuators can only generate bending motions in 2-D space, which greatly limits their applications.
A soft pneumatic network actuator consists of a linearly arranged group of chambers connected by an internal channel. Each cubic chamber contains a pair of opposite walls which are thinner than the other pair and produces a two-sided inflation in the direction perpendicular to the thinner walls. Originally, the thinner walls of the chambers are perpendicular to the long axis of the actuator body and inflate along with the long axis. These collinear inflations in chambers and the non-extensible base lead to an integral pure bending of the actuator. To explore the actuator&#39;s motion in 3-D space, the orientation of the chambers is tuned so that the thinner-side walls are no longer perpendicular to the long axis of the actuator (Figure 1A), which enables the inflation direction of each chamber to offset from the axis and become not collinear. All the parallel but not-collinear inflations change the motion of the actuator into a coupled bending and twisting motion in 3-D space18. This coupled motion enables the actuators more flexibility and dexterity and makes the actuators a suitable candidate for more practical applications, such as flexible manipulators, biologically inspired robots, and medical devices.
This protocol shows the fabrication method of this kind of soft pneumatic network actuators with oblique chambers. It includes preparing the silicone elastomer, fabricating the chamber and base parts, assembling the actuator, connecting the tubing, checking for leaks, and, if necessary, repairing the actuator. It can also be used to fabricate normal soft pneumatic network actuators and other soft actuators which can be produced with some simple modifications to the molding method. We provide detailed steps to fabricate a soft pneumatic actuator with 30&#176; oblique chambers. For different applications, actuators with different chamber angles can be fabricated according to the same protocol. Apart from that, the actuators can be combined to form a multi-actuator system for various demands.

<table><tbody><tr><td>Silicone elastomer</td><td>Wacker</td><td>ELASTOSIL M4601 A/B</td><td>Material of the actuators</td></tr><tr><td>Syringe&amp;nbsp;</td><td>Shanghai Kindly Medical Instruments&amp;nbsp;</td><td>10 ml</td><td>Used to inject silicone rubber into the hole of the mold for fabricating the connection end</td></tr><tr><td>Precision scale</td><td>Shanghai Hochoice</td><td>UTP-313</td><td>Used to weigh the silicone rubber</td></tr><tr><td>Planetary centrifugal vacuum mixer</td><td>THINKY</td><td>ARE-310</td><td>Used to mix the silicone rubber and defoam after mixing process</td></tr><tr><td>Release agent</td><td>Smooth-on</td><td>Release 200</td><td>Used for ease of demolding&amp;nbsp;</td></tr><tr><td>Needle</td><td>Shanghai Kindly Medical Instruments&amp;nbsp;</td><td></td><td>Used for Piercing the bubbles form on the surface</td></tr><tr><td>Utility blade</td><td>M&amp;amp;G Chenguang Stationery</td><td>ASS91325</td><td>Used for Scraping off excess silicone rubber along the upper surface of the mold&amp;nbsp;</td></tr><tr><td>Vacuum oven</td><td>Ningbo SI Instrument</td><td>DZF-6050</td><td>Used to reduce the cure time of the silicone rubber</td></tr><tr><td>Male stud push in fit pneumatic fitting</td><td>Zhe Jiang BLCH Pneumatic Science &amp;amp; Technology</td><td>PC4-01</td><td>Used to connect the tubing and the 3D-printed actuator tubing connector</td></tr><tr><td>Tubing</td><td>SMC</td><td>TU0425</td><td>Used for actuating the actuators</td></tr><tr><td>Vacuum pump</td><td>Zhe Jiang BLCH Pneumatic Science &amp;amp; Technology</td><td></td><td>Used as the air source</td></tr><tr><td>Pressure valve</td><td>Zhe Jiang BLCH Pneumatic Science &amp;amp; Technology</td><td>IR1000-01BG</td><td>Used for adjusting the input air pressure</td></tr></tbody></table>

fabrication of soft pneumatic network actuators with oblique chambers

Soft pneumatic network actuators have become one of the most promising actuation devices in soft robotics which benefits from their large bending deformation and low input. However, their monotonous bending motion form in two-dimensional (2-D) space keeps them away from wide applications. This paper presents a detailed fabrication method of soft pneumatic network actuators with oblique chambers, to explore their motions in three-dimensional (3-D) space. The design of oblique chambers enables actuators with tunable coupled bending and twisting capabilities, which gives them the possibility to move dexterously in flexible manipulators, to become biologically inspired robots and medical devices. The fabrication process is based on the molding method, including the silicone elastomer preparation, chamber and base parts fabrication, actuator assembly, tubing connections, checks for leaks, and actuator repair. The fabrication method guarantees the rapid manufacturing of a series of actuators with only a few modifications in the molds. The test results show the high quality of the actuators and their prominent bending and twisting capabilities. Experiments of the gripper demonstrate the advantages of the development in adapting to objects with different diameters and providing sufficient friction.

Single Actuator: 
To verify the fabrication method and demonstrate the function of the actuator, 30&#176;, 45&#176;, and 60&#176; actuators were fabricated and tested. For the experiment set-up, an air pump was employed to activate the valve. The valve was connected to the actuator to control the internal pressure. The single actuator was fixed at its connection end and placed vertically. While the actuator was being pressurized, two digital cameras were used to capt...

Watch this Scientific Journal Video about Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers at JoVE.com

Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers

Here we present a fabrication method of soft pneumatic network actuators with oblique chambers. The actuators are capable of generating coupled bending and twisting motions, which broadens their application in soft robotics.

Soft pneumatic network actuators have become one of the most promising actuation devices in soft robotics which benefits from their large bending ...

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9.0K Views.  Shanghai Jiao Tong University. Here we present a fabrication method of soft pneumatic network actuators with oblique chambers. The actuators are capable of generating coupled bending and twisting motions, which broadens their application in soft robotics.

Video: Fabrication of Soft Pneumatic Network Actuators with Oblique Chambers

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Bioengineering

Rapid Manufacturing of Thin Soft Pneumatic Actuators and Robots

This protocol describes a method for rapid manufacturing of soft pneumatic actuators and robots with an ultrathin form factor using a heat press and a laser cutter machine. The method starts with the lamination of thermoplastic polyurethane (TPU) sheets using a heat press for 10 min at the temperature of ~93 &#176;C. Next, the parameters of the laser cutter machine are optimized to produce a rectangular balloon with maximum burst pressure. Using the optimized parameters, the soft actuators are laser cut/welded three times sequentially. Next, a dispensing needle is attached to the actuator, allowing it to be inflated. The effect of geometrical parameters on the deflection of the actuator are studied systematically by varying the channel width and length. Finally, the performance of the actuator is characterized using an optical camera and a fluid dispenser. Conventional fabrication methods of soft pneumatic actuators based on silicone molding are time consuming (several hours). They also result in strong but bulky actuators, which limits the actuator&#8217;s applications. Moreover, microfabrication of thin pneumatic actuators is both time-consuming and expensive. The proposed manufacturing method in the current work resolves these issues by introducing a fast, simple, and cost-effective fabrication method of ultrathin pneumatic actuators.

This protocol describes a method for rapid manufacturing of soft pneumatic actuators and robots with a thin form factor. The fabrication method starts with lamination of thermoplastic polyurethane (TPU) sheets followed by laser cutting/welding of a two-dimensional pattern to form actuators and robots.

This protocol describes a method for rapid manufacturing of soft pneumatic actuators and robots with an ultrathin form factor using a heat press and a ...

Rod-based Fabrication of Customizable Soft Robotic Pneumatic Gripper Devices for Delicate Tissue Manipulation

Soft compliant gripping is essential in delicate surgical manipulation for minimizing the risk of tissue grip damage caused by high stress concentrations at the point of contact. It can be achieved by complementing traditional rigid grippers with soft robotic pneumatic gripper devices. This manuscript describes a rod-based approach that combined both 3D-printing and a modified soft lithography technique to fabricate the soft pneumatic gripper. In brief, the pneumatic featureless mold with chamber component is 3D-printed and the rods were used to create the pneumatic channels that connect to the chamber. This protocol eliminates the risk of channels occluding during the sealing process and the need for external air source or related control circuit. The soft gripper consists of a chamber filled with air, and one or more gripper arms with a pneumatic channel in each arm connected to the chamber. The pneumatic channel is positioned close to the outer wall to create different stiffness in the gripper arm. Upon compression of the chamber which generates pressure on the pneumatic channel, the gripper arm will bend inward to form a close grip posture because the outer wall area is more compliant. The soft gripper can be inserted into a 3D-printed handling tool with two different control modes for chamber compression: manual gripper mode with a movable piston, and robotic gripper mode with a linear actuator. The double-arm gripper with two actuatable arms was able to pick up objects of sizes up to 2 mm and yet generate lower compressive forces as compared to elastomer-coated and non-coated rigid grippers. The feasibility of having other designs, such as single-arm or hook gripper, was also demonstrated, which further highlighted the customizability of the soft gripper device, and it's potential to be used in delicate surgical manipulation to reduce the risk of tissue grip damage.

This protocol describes a rod-based approach, combining 3D-printing and soft lithography techniques for fabricating the soft gripper devices. This approach eliminates the need for an external air source by incorporating a chamber component and reduces the chance of occlusion during the sealing process, particularly for miniaturized pneumatic channels.

Soft compliant gripping is essential in delicate surgical manipulation for minimizing the risk of tissue grip damage caused by high stress concentrations ...

Fabrication of Carbon-Based Ionic Electromechanically Active Soft Actuators

Ionic electromechanically active capacitive laminates are a type of smart material that move in response to electrical stimulation. Due to the soft, compliant and biomimetic nature of this deformation, actuators made of the laminate have received increasing interest in soft robotics and (bio)medical applications. However, methods to easily fabricate the active material in large (even industrial) quantities and with a high batch-to-batch and within-batch repeatability are needed to transfer the knowledge from laboratory to industry. This protocol describes a simple, industrially scalable and reproducible method for the fabrication of ionic carbon-based electromechanically active capacitive laminates and the preparation of actuators made thereof. The inclusion of a passive and chemically inert (insoluble) middle layer (e.g., a textile-reinforced polymer network or microporous Teflon) distinguishes the method from others. The protocol is divided into five steps: membrane preparation, electrode preparation, current collector attachment, cutting and shaping, and actuation. Following the protocol results in an active material that can, for example, compliantly grasp and hold a randomly shaped object as demonstrated in the article.

This article describes a fast and simple manufacturing process of ionic electromechanically active composite materials for actuators in biomedical, biomimetic and soft robotics applications. The key fabrication steps, their importance for the actuators&#39; final properties, and some of the main characterization techniques are described in detail.

Ionic electromechanically active capacitive laminates are a type of smart material that move in response to electrical stimulation. Due to the soft, ...

Manufacturing, Control, and Performance Evaluation of a Gecko-Inspired Soft Robot

This protocol presents a method for manufacturing, control, and evaluation of the performance of a soft robot that can climb inclined flat surfaces with slopes of up to 84&#176;. The manufacturing method is valid for the fast pneunet bending actuators in general and might, therefore, be interesting for newcomers to the field of actuator manufacturing. The control of the robot is achieved by means of a pneumatic control box that can provide arbitrary pressures and can be built by only using purchased components, a laser cutter, and a soldering iron. For the walking performance of the robot, the pressure-angle calibration plays a crucial role. Therefore, a semi-automated method for the pressure-angle calibration is presented. At high inclines (&#62; 70&#176;), the robot can no longer reliably fix itself to the walking plane. Therefore, the gait pattern is modified to ensure that the feet can be fixed on the walking plane.

This protocol provides a detailed list of steps to be performed for the manufacturing, control and evaluation of the climbing performance of a gecko-inspired soft robot.

This protocol presents a method for manufacturing, control, and evaluation of the performance of a soft robot that can climb inclined flat surfaces with ...