This project was funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada Industrial Research Chair in Automated Composites Manufacturing and the Fonds de recherche du Qu&#233;bec &#8211; Natrue et technologies (FRQNT).

1. Frame Definitions of the CCM system
NOTE: The optical CMM is a dual camera sensor, which can track the object with a rigid set of reflectors as the targets in real time. The placement principle of these targets is that the targets are stuck at the asymmetric locations with certain distance among them. The targets need to be fixed on the robots or the placement head and remain in the field of view (FOV) of the optical CMM. At least four targets should be observed for each defined frame by the optical CMM all the time. The base frame of the parallel robot, the end-effector frame of the parallel robot, and the tool frame of the serial robot are denoted as Fb, FtP, and FtS, respectively. The definitions of those frames are shown in Figure 1. Because the base frames of the parallel robot and the serial robot are fixed, the transformation matrix between the two base frames can be derived by calibration.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/59969/59969fig1.jpg" /> 
Figure 1. Collaborative Composite Manufacturing (CCM) System Setup. The hardware of the CCM system consists of a 6-RSS parallel robot, a 1-DoF rotational stage, a 6-DoF serial robot, a placement head, and the optical CMM. The mandrel is clamped on the rotational stage, and the rotational stage is mounted on the parallel robot. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/59969/59969fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol>
	<li>Definition of the base frame of the parallel robot
	<ol>
		<li>Load the frame definition file through the software of the optical CMM (see the Table of Materials).</li>
		<li>Click Positioning &#62; Detect Targets. Select the targets that are attached on the motors of the parallel robot. Click Accept to take those targets as the positioning reference of the whole system.</li>
		<li>In the Entities list, click Base Frame and select Make this Reference Frame the Origin. 
		NOTE: The purpose of Step 1.1 is to take Fb as the reference frame of the whole system. The frame definition file can be obtained at the following link: &#60;https://users.encs.concordia.ca/~wfxie/Jove_program/P3.csf&#62;.</li>
	</ol>
	</li>
	<li>Definition of the tracking model of the end-effector platform frame
	<ol>
		<li>Select Tracking Models in the navigation area. Click Detect Model, and then select the targets fixed on the end-effector platform of the parallel robot. Click Accept.</li>
		<li>Click the generated detection model. Select Up_Frame in the drop-down list of the Origin Offset. Then click Apply. 
		NOTE: This step is to set up the fixed relationships between the end-effector platform frame FtP and the targets attached on the end-effector platform.</li>
		<li>Click File-Export-Tracking model, and enter a file name to save the tracking model.</li>
	</ol>
	</li>
	<li>Definition of the tracking model of the tool frame
	<ol>
		<li>Select Tracking Models. Click Detect Model, then select the targets fixed on the tool frame of the serial robot. Click Accept.</li>
		<li>Click the generated detection model. Select SerToolFrame in the drop-down list of the Origin offset. Click Apply and save the defined tracking model.</li>
	</ol>
	</li>
</ol>
2. System Preparation
NOTE: The control system layout of the CCM system is shown in Figure 2.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/59969/59969fig2.jpg" /> 
Figure 2. System Layout. Two computers (A &#38; B) are used for controlling the CCM system. The communication between them is via RS232. Computer A controls the rotational state, photogrammetry senor and serial robot. Computer B controls the parallel robot, motors and valves etc. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/59969/59969fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol>
	<li>Preparation of the rotational stage
	<ol>
		<li>Load the integrated control interface programed by event-driven programming language on computer A. 
		NOTE: The control interface is shown in Figure 3. The interface program can be obtained at the following link: &#60;https://users.encs.concordia.ca/~wfxie/Jove_program/pcdk-ctrack.rar&#62;.</li>
		<li>Click Connect to connect the controller of the rotational stage. Click Enable to connect the motor of rotational stage. Then click Home to move the rotational stage to the home position.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/59969/59969fig3.jpg" /> 
Figure 3. Control Interface. The control software programmed by event-driven programming language. The interface is composed of 6 sections: serial robot, parallel robot, rotational stage, path import, optical CMM and cooperative control. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/59969/59969fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Preparation of the serial robot
	<ol>
		<li>Power on the controller of the serial robot (see the Table of Materials).</li>
		<li>Click Connect on the integrated control interface to connect the robot server.</li>
	</ol>
	</li>
	<li>Preparation of the Optical CMM
	<ol>
		<li>Power on the controller of the optical CMM and wait until the screen of the controller shows Ready.</li>
		<li>Click Connect on the integrated control interface to connect the optical CMM via Application Programming Interface (API).</li>
		<li>Import the models built in section 1, which includes the Base model, the Upper platform model and the End-effector model of the serial robot.</li>
		<li>Click Add Sequence. Add the relative sequence between the models if it is necessary. Then click Start Tracking to track the pose of the models.</li>
	</ol>
	</li>
	<li>Preparation of the Parallel robot
	<ol>
		<li>Power on the controller of the parallel robot.</li>
		<li>Load the SerialPort_Receive program and select Normal mode. 
		NOTE: The SerialPort_Receive program cannot control the parallel robot directly. It is used to receive the remote data from computer A via serial communication port. The SerialPort_Receive program can be obtained at the following link: &#60;https://users.encs.concordia.ca/~wfxie/Jove_program/SerialPort_Receive.mdl&#62;.</li>
		<li>Load the ParaRemoteControl program and select External mode. Then click Incremental Build to connect to target. 
		NOTE: The ParaRemoteControl program is used to receive the desired pose from SerialPort_Receive program and control the parallel robot. The ParaRemoteControl program can be obtained at the following link: &#60;https://users.encs.concordia.ca/~wfxie/Jove_program/ParaRemoteControl.mdl&#62;.</li>
		<li>Click Start Simulation of the two programs to initialize the controller of the parallel robot.</li>
	</ol>
	</li>
</ol>
3. Generating the off-line path
<ol>
	<li>Load the path planning interface through the numerical computing software (see the Table of Materials). 
	NOTE: The interface is shown in Figure 4. The path planning interface is the off-line software to generate the path for the system and can be obtained at the following link: &#60;https://users.encs.concordia.ca/~wfxie/Jove_program/AFP_PathPlanning_Pcode.zip&#62;.</li>
</ol>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/59969/59969fig4.jpg" /> 
Figure 4. Path Planning Interface. The path planning software is composed of 3 sections: Visual Area, Command Area and Information Box. The &#34;Viewing Area&#34; section allows the 3D display of the parts to be processed. The &#34;Command Area&#34; section is to perform the main actions for generating the off-line path. The &#34;Information Box&#34; section displays the information about the status of the program. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/59969/59969fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Click Import STL and choose the part file. Then click Segmentation. 
	NOTE: The part is divided into separated regions (cylinders and junctions of Y-shape part). The different regions are displayed in different colors.</li>
	<li>Click Add Work Region and select the region on the extraction of cylinders.</li>
	<li>Adjust the slider to 100% and click Extract Cylinders.</li>
	<li>Click Add Work Region to select the starting branch of the path.</li>
	<li>Click Generate Path. Choose the third option: Constant Placement Angle (CPA) in the pop-up dialog window.</li>
	<li>Choose the desired placement angle 90&#176; in the pop-up dialogue window. Then choose the red dot.</li>
	<li>To display the generated path, click Select a Path drop-down menu. Then, select the path.</li>
	<li>To save this path, click File &#62; Save and enter a file name.</li>
</ol>
4. Individual decomposition of the trajectory for the serial robot and rotational stage
<ol>
	<li>Run the Methode_Jacobian function in the numerical computing software (see Table of Materials). 
	NOTE: Methode_Jacobian function is used to decompose the generated path in Step 3 into two individual trajectories for the serial robot and the rotational stage.</li>
	<li>Select the desired path file (generated by path planning interface) and click open.</li>
	<li>Enter the desired path number.</li>
	<li>The first point of the trajectory is then calculated. Choose the desired configuration for the manipulator to reach this pose. 
	NOTE: When Step 4.4 is completed, a graph showing the evolution of joint values is displayed. A file containing the trajectory for the serial robot and the rotational stage is generated.</li>
</ol>
5. Running the off-line path without the path modification algorithm
<ol>
	<li>Press Select on the teach pendant and choose the name of the imported file. Press Enter to load the path file.</li>
	<li>Turn the switch of the robot controller to Auto mode. Turn the teach pendant ON/OFF switch to Off.</li>
	<li>Press Cycle Start of the controller of the serial robot to run the path.</li>
	<li>Click Cooperative Move located at the Cooperative Control panel. 
	NOTE: The system will execute the offline path without the on-line path modification algorithm. If the joint reaches to the singularity or constraint condition, the system will stop.</li>
</ol>
6. Running the off-line path with the path modification algorithm
<ol>
	<li>Repeat steps 5.1&#8211;5.3. Then click DPM Connect located at the Cooperative Control panel in Figure 3 to add the on-line path modification ability for the system.</li>
	<li>Click Cooperative Move located at the Cooperative Control panel. 
	NOTE: The system will execute the offline path with the on-line path modification algorithm. During the execution, the singularities and joints&#8217; constraints are monitored through the encoder measurement of the serial robot. The system can smoothly pass the singularity or constraint limitation points without termination.</li>
</ol>

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The authors have nothing to disclose.

The experimental results show the manufacturing process of 90&#176; ply placement angles of the designed CCM system. The methodologies proposed in this paper can be used to lay up the fiber with 0&#176; and 45&#176; ply placement angles on the mandrel with Y-Shape and other shapes. While the built-in controller of the serial robot is able to provide the singularity avoidance feature17, only linear movement of the end-effector is supported. When the end-effector executes the task of the circle move...

Recently, the increasing need for high performance composite structures in various industries has greatly driven the development of the composite manufacturing technologies1,2. The traditional manual production cannot meet the high efficiency, accuracy and quality requirement of emerging industry. This aspect has encouraged the development of new production technologies such as AFP systems. The AFP technology automates the production of composite material structures using prepregs, which are present in the form of strips composed of impregnated fiber tapes (glass, carbon, etc.) of semi-polymerized resin. In the AFP system, a deposition head with the ability of heating and compacting the resin prepregs is mounted on a fiber placement machine or an industrial robot. The fiber placement machine or robot carrying the deposition head lays up the prepregs traversing the surface of the tooling mandrels. In the process of manufacturing, the tooling mandrel is used as a mold to be wound around by the prepregs to form a certain structure of composite part. The mandrel will be removed after the part is cured. The current AFP systems can significantly improve the efficiency and quality of the production of composite materials3,4,5. However, they are limited to the production of the open surfaces presenting a flat or contoured surface, or simple revolution parts such as cylinders or cones due to the insufficient DoF of the system and the difficulties in generating trajectories. Especially, the aerospace industry and the production industries of sports equipment are now interested in this technique for the production of structures with more complex geometries, like &#34;Y&#34; tubes or the structures forming closed-loops such as bicycle frames.
To be able to manufacture the structures with complex geometries, the flexibility of the AFP system should be improved. For example, an 8 DoF AFP system has been proposed6 by adding a linear track to a 6 DoF industrial robot and a rotational stage to the mandrel holding platform. However, the system is still not suitable for manufacturing the above-mentioned parts with complex geometries. The collaborative robotic system consisting of two robots is a promising solution to increase the dexterity by employing one robot to hold the fiber placement head at the end-effector and another robot to hold the mandrel. The two-serial-robot collaborative system may not solve the fiber placement problem, since the serial robots tend to deform and lose the accuracy due to its cantilever structure, considering the weight of the mandrel and the compaction force7. Compared with the serial robots, 6 DoF parallel robots, which have been utilized in the flight simulator and medical tools, enjoy better stiffness and accuracy8. Therefore, a parallel-serial collaborative robot system, in additional to a rotational stage mounted on the platform of the parallel robot, is built for handling the complex structures manufacturing in this paper.
However, the built collaborative robotic system yields difficulties in designing the controller for each robot to meet the high accuracy requirement of fiber placement. The accurate position measurement of the end-effector could be achieved by using laser tracking system, which is commonly used to guide the industrial robot in various aerospace drilling applications9,10. Although the laser tracking system can provide high accurate position measurement, the main drawbacks lie in the cost of the system and the occlusion issue. The laser tracking system is expensive, e.g., a commercial laser tracker and its accessories cost up to US$90,000, and the laser beam is easily occluded during the movement of the robots. Another promising solution is the vision measurement system, which can provide 6D pose measurement of the end-effector with a considerable accuracy at a low cost. The pose is referred to as the combination of the 3D position and 3D orientation of the end-effector with respect to the base frame of the robot. The optical CMM (see Table of Materials) is a dual camera-based visual sensor. By observing several reflector targets attached on the end-effectors of the two robots, the relative poses between the robots can be measured in real time. The optical CMM has been successfully applied to the robotic calibration11 and dynamic path tracking12 and thus is introduced to provide the feedback measurement to the closed-loop control systems of the proposed CCM system in this study.
The quality of the end composite product is largely dependent on how the original fiber path is generated for the AFP13,14. The path generation process is normally performed by using off-line programming software. The generated path consists of a series of tag points on the mandrel, which indicate the pose of the fiber placement head. Unlike other trajectory planning applications such as paint deposition, polishing or machining, where different types of coverage paths are possible, the choice is limited in the case of AFP, since the fiber is continuous and it is not possible to perform abrupt changes in direction (sharp corners) without damaging it and the placement head should be kept in the norm of the surface of the parts. The first development of trajectory generation technique for AFP has been concentrated on manufacturing large flat panels5 before moving towards the manufacturing the objects of 3D shapes such as open curved surfaces or cones5,14. But, no practical methodology has been developed for generating off-line path for the parts with complex geometries such as Y-shape or the other shapes. Therefore, an effective path planning algorithm for the parts with complex-contoured surfaces is designed to ensure uniform lay-up of subsequent fibers without gaps or overlaps in our previous research15. Considering the practicality and the effectiveness of the path generating algorithm, only the 6-DoF serial robot with the placement head and 1-DoF rotational stage as the mandrel holder are considered as the target system to find the optimum trajectory planning in joint space with minimum time criteria. It could be too complicated and time-consuming to generate the off-line trajectory for the whole 13 DoF CCM system due to the heavy kinematics calculation and the consideration of various constraints like singularities, collisions, smooth direction changing and keeping the placement head in the norm of the parts surface, etc.
The proposed off-line trajectory planning can generate the servo reference for the 6 DoF serial robot and the rotational stage respectively with exact timing. Even with this off-line trajectory planning, it could be impossible to generate a feasible path under all the constraints for certain geometry parts. Moreover, the positioning errors of the robots may cause the robots to collide with the mandrel or another device in the working environment. The on-line path modification is implemented based on the visual feedback from the optical CMM. Therefore the on-line pose correction algorithm is proposed to correct the path of the parallel robot and to tune a corresponding offset on the path of the serial robot simultaneously through the visual feedback. When the collision and other constraints are detected, the relative pose between the two robots is also kept unchanged while following the off-line generated path. Through the correction of the on-line path, the CCM system can avoid these points smoothly without any termination. Due to the flexibility of the parallel robot, the 6D correction offsets can be generated with respect to different constraints. This manuscript presents a detailed operation procedure of the CCM system using on-line pose correction algorithm.

<table>
	<tbody>
		<tr>
			<td>AeroBasic</td>
			<td>Aerotech</td>
			<td></td>
			<td>Motion control software</td>
		</tr>
		<tr>
			<td>Collaborative Composite Manufacturing (CCM) System</td>
			<td>Concordia University</td>
			<td></td>
			<td>A CCM system is proposed to manufacture more complex composite components which pose high demand for trajectory planning than those by the current AFP system. The system consists of a 6 degree-of-freedom (DOF) serial robot holding the fiber placement head, a 6-DOF revolute-spherical-spherical (RSS) parallel robot on which a 1-DOF mandrel holder is installed and an eye-to-hand optical CMM sensor, i.e. C-track, to detect the poses of both end-effectors of parallel robot and serial robot.</td>
		</tr>
		<tr>
			<td>C-track</td>
			<td>Creaform Inc.</td>
			<td></td>
			<td>An eye-to-hand optical CMM sensor</td>
		</tr>
		<tr>
			<td>Fanuc M-20iA</td>
			<td>Fanuc Inc.</td>
			<td></td>
			<td>Serial robot</td>
		</tr>
		<tr>
			<td>Matlab</td>
			<td>MathWorks</td>
			<td></td>
			<td>A multi-paradigm numerical computing software</td>
		</tr>
		<tr>
			<td>Quanser</td>
			<td>Quanser Inc.</td>
			<td></td>
			<td>Providing the engineering lab equipments for teaching and research.</td>
		</tr>
		<tr>
			<td>VB</td>
			<td>Microsoft</td>
			<td></td>
			<td>Visual Basic</td>
		</tr>
		<tr>
			<td>Vxelements</td>
			<td>Creaform Inc.</td>
			<td></td>
			<td>Software for C-track</td>
		</tr>
	</tbody>
</table>

operation of the collaborative composite manufacturing (ccm) system

The automated tape placement and the automated fiber placement (AFP) machines provide a safer working environment and reduce the labor intensity of workers than the traditional manual fiber placement does. Thus, the production accuracy, repeatability and efficiency of composite manufacturing are significantly improved. However, the current AFP systems can only produce the composite components with large open surface or simple revolution parts, which cannot meet the growing interest in small complex or closed structures from industry.
In this research, by employing a 1-degree of freedom (DoF) rotational stage, a 6-RSS parallel robot, and a 6-DoF serial robot, the dexterity of the AFP system can be significantly improved for manufacturing complex composite parts. The rotational stage mounted on the parallel robot is utilized to hold the mandrel and the serial robot carries the placement head to mimic two human hands that have enough dexterity to lay the fiber to the mandrel with complex contour.
Although the CCM system increases the flexibility of composite manufacturing, it is quite time-consuming or even impossible to generate the feasible off-line path, which ensures uniform lay-up of subsequent fibers considering the constraints like singularities, collisions between the fiber placement head and mandrel, smooth fiber direction change and keeping the fiber placement head along the norm of the part&#39;s surface, etc. Moreover, due to the existing positioning error of the robots, the on-line path correction is needed. Therefore, the on-line pose correction algorithm is proposed to correct the paths of both parallel and serial robots, and to keep the relative path between the two robots unchanged through the visual feedback when the constraint or singularity problems in the off-line path planning occur. The experimental results demonstrate the designed CCM system can fulfill the movement needed for manufacturing a composite structure with Y-shape.

The experiment aims at demonstrating the process of realizing the motion of laying up the fiber on the Y-shape mandrel of the proposed CCM system. The process is carried out in three steps: path generation; trajectory decomposition; and singularity and constraint avoidance.
Path generation 
Normally, the standard orientation is used in industry to define the different plies of the laminate. In this paper, t...

Watch this Scientific Journal Video about Operation of the Collaborative Composite Manufacturing CCM System at JoVE.com

Operation of the Collaborative Composite Manufacturing CCM System

A collaborative composite manufacturing system is developed for robotic lay-up of composite laminates using the prepreg tape. The proposed system allows the production of composite laminates with high levels of geometrical complexity. The issues in the path planning, coordination of the robots and control are addressed in the proposed method.

Operation of the Collaborative Composite Manufacturing (CCM) System

The automated tape placement and the automated fiber placement (AFP) machines provide a safer working environment and reduce the labor intensity of ...

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Universidad de Cartagena UDEC

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SCIENTISTS IN ACTION

6.5K Views.  Concordia University. A collaborative composite manufacturing system is developed for robotic lay-up of composite laminates using the prepreg tape. The proposed system allows the production of composite laminates with high levels of geometrical complexity. The issues in the path planning, coordination of the robots and control are addressed in the proposed method.

Video: Operation of the Collaborative Composite Manufacturing CCM System

Fabrication and Operation of a Nano-Optical Conveyor Belt

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and&#160;limits the&#160;resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

The scalability and resolution of conventional optical manipulation techniques are limited by diffraction. We circumvent the diffraction limit and describe a method of optically transporting nanoparticles across a chip using a gold surface patterned with a path of closely spaced C-shaped plasmonic resonators.

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological ...

Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto silicon (Si) substrates via different synthesized temperatures by using plasma enhanced chemical vapor deposition (PECVD) system. The effects of different synthesized temperatures on the crystal structure, surface morphologies and optical properties have been investigated. The X-ray diffraction (XRD) patterns indicated that the intensity of (0002) diffraction peak became stronger with increasing synthesized temperature until 400 oC. The diffraction intensity of (0002) peak gradually became weaker accompanying with appearance of (10-10) diffraction peak as the synthesized temperature up to excess of 400 oC. The RT photoluminescence (PL) spectra exhibited a strong near-band-edge (NBE) emission observed at around 375 nm and a negligible deep-level (DL) emission located at around 575 nm under high c-axis ZnO thin films. Field emission scanning electron microscopy (FE-SEM) images revealed the homogeneous surface and with small grain size distribution. The ZnO thin films have also been synthesized onto glass substrates under the same parameters for measuring the transmittance.
For the purpose of ultraviolet (UV) photodetector application, the interdigitated platinum (Pt) thin film (thickness ~100 nm) fabricated via conventional optical lithography process and radio frequency (RF) magnetron sputtering. In order to reach Ohmic contact, the device was annealed in argon circumstances at 450 oC by rapid thermal annealing (RTA) system for 10 min. After the systematic measurements, the current-voltage (I-V) curve of photo and dark current and time-dependent photocurrent response results exhibited a good responsivity and reliability, indicating that the high c-axis ZnO thin film is a suitable sensing layer for UV photodetector application.

We offered a method to directly synthesize high c-axis (0002) ZnO thin film by plasma enhanced chemical vapor deposition. The as-synthesized ZnO thin film combined with Pt interdigitated electrode was used as sensing layer for ultraviolet photodetector, showing a high performance through a combination of its good responsivity and reliability.

In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto ...

Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 &#181;m thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm2 and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 &#176;C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 &#730;C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells.

This paper investigates the suitability of inkjet printing for the manufacturing of dye-sensitized solar cells. A binder-free TiO2 nanoparticle ink was formulated and printed onto a FTO glass substrate. The printed layer was fabricated into a cell with an active area of 0.25 cm2 and an efficiency of 3.5%.

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less ...

Testing of Nanoparticle Release from a Composite Containing Nanomaterial Using a Chamber System

With the rapid development of nanotechnology as one of the most important technologies in the 21st century, interest in the safety of consumer products containing nanomaterials is also increasing. Evaluating the nanomaterial release from products containing nanomaterials is a crucial step in assessing the safety of these products, and has resulted in several international efforts to develop consistent and reliable technologies for standardizing the evaluation of nanomaterial release. In this study, the release of nanomaterials from products containing nanomaterials is evaluated using a chamber system that includes a condensation particle counter, optical particle counter, and sampling ports to collect filter samples for electron microscopy analysis. The proposed chamber system is tested using an abrasor and disc-type nanocomposite material specimens to determine whether the nanomaterial release is repeatable and consistent within an acceptable range. The test results indicate that the total number of particles in each test is within 20% from the average after several trials. The release trends are similar and they show very good repeatability. Therefore, the proposed chamber system can be effectively used for nanomaterial release testing of products containing nanomaterials.

Nanoparticle release is tested using a chamber system that includes a condensation particle counter, an optical particle counter and sampling ports to collect filter samples for microscopy analysis. The proposed chamber system can be effectively used for nanomaterial release testing with a repeatable and consistent data range.

With the rapid development of nanotechnology as one of the most important technologies in the 21st century, interest in the safety of consumer products ...

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...

Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed magnet assisted composite manufacturing (MACM) technique. In this technique, permanent magnets are utilized to apply a sufficiently high consolidation pressure during the curing stage. To enhance the intensity of the magnetic field, and thus, to increase the magnetic compaction pressure, the magnets are placed on a magnetic top plate. First, the entire procedure of preparing the composite lay-up on a magnetic bottom steel plate using the conventional wet lay-up vacuum bag process is described. Second, placement of a set of Neodymium-Iron-Boron permanent magnets, arranged in alternating polarity, on the vacuum bag is illustrated. Next, the experimental procedures to measure the magnetic compaction pressure and volume fractions of the composite constituents are presented. Finally, methods used to characterize microstructure and mechanical properties of composite laminates are discussed in detail. The results prove the effectiveness of the MACM method in improving the quality of wet lay-up vacuum bag laminates. This method does not require large capital investment for tooling or equipment and can also be used to consolidate geometrically complex composite parts by placing the magnets on a matching top mold positioned on the vacuum bag.

A new technique for applying consolidation pressure on the vacuum bag lay-up to fabricate composite laminates is described. The goal of this protocol is to develop a simple, cost-effective technique to improve the quality of laminates fabricated by the wet lay-up vacuum bag method.

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed ...

Additive Manufacturing of Functionally Graded Ceramic Materials by Stereolithography

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light processing/stereolithography, is developed within the scope of the CerAMfacturing European research project. A three-dimensional (3-D) hemi-maxillary bone-like structure is 3-D printed using custom aluminum oxide polymeric mixtures. The powders and mixtures are fully analyzed in terms of rheological behavior in order to ensure proper material handling during the printing process. The possibility to print functionally graded materials using the Admaflex technology is explained in this document. Field-emission scanning electron microscopy (FESEM) show that the sintered aluminum oxide ceramic part has a porosity lower than 1% and no remainder of the original layered structure is found after analysis.

This manuscript describes the processing of single multifunctional ceramic components (e.g., combinations of dense-porous structures) additively manufactured by stereolithography.

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light ...

Construction and Operation of a Light-driven Gold Nanorod Rotary Motor System

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and artificial nanomotors and may provide new routes towards single cell analysis, studies of non-equilibrium thermodynamics, and mechanical actuation of nanoscale systems. A facile way to drive rotation is to use focused circularly polarized laser light in optical tweezers. Using this approach, metallic nanoparticles can be operated as highly efficient scattering-driven rotary motors spinning at unprecedented rotation frequencies in water.
In this protocol, we outline the construction and operation of circularly-polarized optical tweezers for nanoparticle rotation and describe the instrumentation needed for recording the Brownian dynamics and Rayleigh scattering of the trapped particle. The rotational motion and the scattering spectra provides independent information on the properties of the nanoparticle and its immediate environment. The experimental platform has proven useful as a nanoscopic gauge of viscosity and local temperature, for tracking morphological changes of nanorods and molecular coatings, and as a transducer and probe of photothermal and thermodynamic processes.

Plasmonic gold nanorods can be trapped in liquids and rotated at kHz frequencies using circularly-polarized optical tweezers. Introducing tools for Brownian dynamics analysis and light scatteringspectroscopy leads to a powerful system for research and application in numerous fields of science.

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and ...

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 ...

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 ...