Design of a Novel Locking Ratcheting Mechanism for a Body-Powered Underactuated Hand

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Hun Chan Lee ◽  
Raymond Cipra
Keyword(s):  
Three Dimensional ◽  
Prosthetic Hand ◽  
3D Printer ◽  
Force Analysis ◽  
Joint Angles ◽  
Actual System ◽  
Prosthetic Hands ◽  
Awkward Position ◽  
3D Printers ◽  
Different Shapes

Abstract As affordable and efficient three-dimensional (3D) printers became widely available, researchers are focusing on developing prosthetic hands that are reasonably priced and effective at the same time. By allowing anyone with a 3D printer to build a body-powered prosthetic hand, many people could build their own prosthetic hand. However, one of the major problems with the current designs is the users must bend and hold their wrist in an awkward position to grasp an object. The primary goal of this work is to present the design process and analysis of a body-powered underactuated prosthetic hand with a novel ratcheting mechanism that locks the finger automatically at a desired position. To estimate how a compliant finger behaves on the actual system with the ratcheting mechanism, the preshaping analysis and the preshaping experiment were conducted. From the experiment, the presence of elastic hysteresis was observed. Additionally, the contact force analysis was performed to see the effects of joint angles and applied tension force. To test how well the hand can grasp, a cup with various weights was lifted and various objects with different shapes were grasped to prove how well the compliant finger can adapt to the shape of the objects. Based on the experiment, the hand had a higher success rate of grasping objects that are lightweight (less than 500 g) and cylindrical or circular shaped.

scholarly journals Implementing a 3D printing service in a biomedical library

2017 ◽  
Vol 105 (1) ◽  
Author(s):  
Verma Walker, MLIS
Keyword(s):  
Problem Solving ◽  
3D Printing ◽  
3D Modeling ◽  
Three Dimensional ◽  
National Institutes Of Health ◽  
3D Printer ◽  
Service Model ◽  
Steep Learning Curve ◽  
3D Printers ◽  
Creative Problem

Three-dimensional (3D) printing is opening new opportunities in biomedicine by enabling creative problem solving, faster prototyping of ideas, advances in tissue engineering, and customized patient solutions. The National Institutes of Health (NIH) Library purchased a Makerbot Replicator 2 3D printer to give scientists a chance to try out this technology. To launch the service, the library offered training, conducted a survey on service model preferences, and tracked usage and class attendance. 3D printing was very popular, with new lab equipment prototypes being the most common model type. Most survey respondents indicated they would use the service again and be willing to pay for models. There was high interest in training for 3D modeling, which has a steep learning curve. 3D printers also require significant care and repairs. NIH scientists are using 3D printing to improve their research, and it is opening new avenues for problem solving in labs. Several scientists found the 3D printer so helpful they bought one for their labs. Having a printer in a central and open location like a library can help scientists, doctors, and students learn how to use this technology in their work.

scholarly journals 3D Printing: What Are the Hazards?

2018 ◽  
Vol 66 (3) ◽  
pp. 164-164 ◽  
Author(s):  
Susan A. Randolph
Keyword(s):  
3D Printing ◽  
Occupational Health ◽  
Health Professionals ◽  
Three Dimensional ◽  
3D Printer ◽  
3D Printers

As the popularity of three-dimensional (3D) printers increases, more research will be conducted to evaluate the benefits and risks of this technology. Occupational health professionals should stay abreast of new recommendations to protect workers from exposure to 3D printer emissions.

scholarly journals Characterization of Ultrafine Particles and VOCs Emitted from a 3D Printer

2021 ◽  
Vol 18 (3) ◽  
pp. 929
Author(s):  
Sarka Bernatikova ◽  
Ales Dudacek ◽  
Radka Prichystalova ◽  
Vit Klecka ◽  
Lucie Kocurkova
Keyword(s):  
Ultrafine Particles ◽  
Three Dimensional ◽  
Personal Exposure ◽  
Gas Chromatography Mass Spectrometry ◽  
3D Printer ◽  
The Public ◽  
Low Concentrations ◽  
Total Particle ◽  
3D Printers

Currently, widely available three-dimensional (3D) printers are very popular with the public. Previous research has shown that these printers can emit ultrafine particles (UFPs) and volatile organic compounds (VOCs). Several studies have examined the emissivity of filaments from 3D printing, except glycol modified polyethylene terephthalate (PETG) and styrene free co-polyester (NGEN) filaments. The aim of this study was to evaluate UFP and VOC emissions when printing using a commonly available 3D printer (ORIGINAL PRUSA i3 MK2 printer) using PETG and NGEN. The concentrations of UFPs were determined via measurements of particle number concentration and size distribution. A thermal analysis was carried out to ascertain whether signs of fiber decomposition would occur at printing temperatures. The total amount of VOCs was determined using a photoionization detector, and qualitatively analyzed via gas chromatography-mass spectrometry. The total particle concentrations were 3.88 × 1010 particles for PETG and 6.01 × 109 particles for NGEN. VOCs at very low concentrations were detected in both filaments, namely ethylbenzene, toluene, and xylene. In addition, styrene was identified in PETG. On the basis of our results, we recommend conducting additional measurements, to more accurately quantify personal exposure to both UFPs and VOCs, focusing on longer exposure as it can be a source of potential cancer risk.

scholarly journals Educational Value of a 3D Printer in Ophthalmology Training

2018 ◽  
Vol 10 (01) ◽  
pp. e69-e71
Author(s):  
Jawad Arshad ◽  
Richard Helms ◽  
Faruk Orge ◽  
Rony Sayegh
Keyword(s):  
Medical Students ◽  
Surgical Planning ◽  
Three Dimensional ◽  
3D Printer ◽  
Slit Lamp ◽  
Educational Value ◽  
Device Development ◽  
Custom Made ◽  
Department Of Ophthalmology ◽  
3D Printers

AbstractThree-dimensional (3D) printers are increasingly being used in medicine for surgical planning, medical education, patient education, research, and device development. We explore the educational value of a 3D printer for trainees in an ophthalmology residency program. A 3D printer was made available to medical students, residents, and clinical and research fellows in the Department of Ophthalmology at Case Western Reserve University. One of the medical students was proficient in the technology and was available to help. Multiple projects were initiated including the manufacturing of slit-lamp cellphone adapters and various interface and integral custom-made parts for research applications. The 3D printer was found to be useful by 20 of 21 trainees surveyed with 17 of 20 saying they would use it after graduation if they had access to one. All the respondents felt that the availability of the technology can contribute to increased innovation in the ophthalmology department. We encourage other ophthalmology departments to experiment with 3D printing as a tool to foster innovation and creativity for trainees.

scholarly journals A myoelectric prosthetic hand with muscle synergy–based motion determination and impedance model–based biomimetic control

2019 ◽  
Vol 4 (31) ◽  
pp. eaaw6339 ◽  
Author(s):  
Akira Furui ◽  
Shintaro Eto ◽  
Kosuke Nakagaki ◽  
Kyohei Shimada ◽  
Go Nakamura ◽  
...  
Keyword(s):  
Upper Limb ◽  
Impedance Control ◽  
Three Dimensional ◽  
Human Motion ◽  
Muscle Synergy ◽  
Prosthetic Hand ◽  
Control Mechanisms ◽  
Finger Movements ◽  
Prosthetic Hands

Prosthetic hands are prescribed to patients who have suffered an amputation of the upper limb due to an accident or a disease. This is done to allow patients to regain functionality of their lost hands. Myoelectric prosthetic hands were found to have the possibility of implementing intuitive controls based on operator’s electromyogram (EMG) signals. These controls have been extensively studied and developed. In recent years, development costs and maintainability of prosthetic hands have been improved through three-dimensional (3D) printing technology. However, no previous studies have realized the advantages of EMG-based classification of multiple finger movements in conjunction with the introduction of advanced control mechanisms based on human motion. This paper proposes a 3D-printed myoelectric prosthetic hand and an accompanying control system. The muscle synergy–based motion-determination method and biomimetic impedance control are introduced in the proposed system, enabling the classification of unlearned combined motions and smooth and intuitive finger movements of the prosthetic hand. We evaluate the proposed system through operational experiments performed on six healthy participants and an upper-limb amputee participant. The experimental results demonstrate that our prosthetic hand system can successfully classify both learned single motions and unlearned combined motions from EMG signals with a high degree of accuracy. Furthermore, applications to real-world uses of prosthetic hands are demonstrated through control tasks conducted by the amputee participant.

Additive-Manufactured Organic Interposers

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
A. Roshanghias ◽  
M. Krivec ◽  
J. Bardong ◽  
A. Binder
Keyword(s):  
Flip Chip ◽  
Three Dimensional ◽  
Heterogeneous Integration ◽  
3D Printer ◽  
3D Integration ◽  
Wire Bond ◽  
3D Printers ◽  
Additional Costs ◽  
3D Printed ◽  
Flexible Die

Abstract The trend toward heterogeneous integration of optoelectronic, electronic, and micromechanical components favors three-dimensional (3D) integration in which the components are not arranged side-by-side but rather in vertical stacks. This presents a particular challenge due to the fact that the stacked components have different geometric dimensions, and their contact surfaces are also dissimilar. Therefore, an intermediate substrate, the so-called interposer, with different formats (i.e., flip-chip, wire-bond, and hybrid flip-chip/wire bond) comes into play. Currently, the interposers are mainly made of silicon or glass, which incur huge additional costs to the packaged components. In this study, the unique advantages of additive manufacturing (AM) are exploited to realize organic interposers. The proposed interposers provide easy signal probing and flexible die-to-board integration in lower costs without any lithography process, drilling, plating, or any waste. Accordingly, the two state-of-the-art 3D printers (i.e., a monomaterial 3D printer and a bimaterial 3D printer) were utilized for the manufacturing of the interposer parts. The complementary circuitry for vias and through-holes was facilitated by also additive technologies, i.e., 2D-inkjet printing and microdispensing. Moreover, and to manifest the unique possibilities within AM for the next generation of interposers, two examples for 3D-printed interposers with incorporated added-features, i.e., pillars for flip-chip bonding and cavities for face-up die-attachment were realized. The assemblies were consequently assessed by electrical examinations. Conclusively, the main opportunities and challenges toward the full implementation of AM technology for the fabrication of organic interposers with added-features such as integrated multipurpose vias were discussed. Based on the results obtained from this study, it was found that bimaterial 3D printer was more efficient and powerful for the construction of interposers.

scholarly journals Efficient 3D printing via photooxidation of ketocoumarin based photopolymerization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoyu Zhao ◽  
Ye Zhao ◽  
Ming-De Li ◽  
Zhong’an Li ◽  
Haiyan Peng ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Visible Light ◽  
Light Exposure ◽  
Three Dimensional ◽  
3D Printer ◽  
Light Penetration ◽  
Viable Solution

AbstractPhotopolymerization-based three-dimensional (3D) printing can enable customized manufacturing that is difficult to achieve through other traditional means. Nevertheless, it remains challenging to achieve efficient 3D printing due to the compromise between print speed and resolution. Herein, we report an efficient 3D printing approach based on the photooxidation of ketocoumarin that functions as the photosensitizer during photopolymerization, which can simultaneously deliver high print speed (5.1 cm h−1) and high print resolution (23 μm) on a common 3D printer. Mechanistically, the initiating radical and deethylated ketocoumarin are both generated upon visible light exposure, with the former giving rise to rapid photopolymerization and high print speed while the latter ensuring high print resolution by confining the light penetration. By comparison, the printed feature is hard to identify when the ketocoumarin encounters photoreduction due to the increased lateral photopolymerization. The proposed approach here provides a viable solution towards efficient additive manufacturing by controlling the photoreaction of photosensitizers during photopolymerization.

scholarly journals Supercritical Impregnation of PLA Filaments with Mango Leaf Extract to Manufacture Functionalized Biomedical Devices by 3D Printing

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2125
Author(s):  
José María Rosales ◽  
Cristina Cejudo ◽  
Lidia Verano ◽  
Lourdes Casas ◽  
Casimiro Mantell ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
3D Printing ◽  
Polylactic Acid ◽  
Leaf Extract ◽  
Three Dimensional ◽  
3D Printer ◽  
Pharmacological Properties ◽  
Bioactive Properties ◽  
Supercritical Impregnation ◽  
Mango Leaves

Polylactic Acid (PLA) filaments impregnated with ethanolic mango leaves extract (MLE) with pharmacological properties were obtained by supercritical impregnation. The effects of pressure, temperature and amount of extract on the response variables, i.e., swelling, extract loading and bioactivity of the PLA filaments, were determined. The analysis of the filaments biocapacities revealed that impregnated PLA filaments showed 11.07% antidenaturant capacity and 88.13% antioxidant activity, which after a 9-day incubation shifted to 30.10% and 9.90%, respectively. Subsequently, the same tests were conducted on printed samples. Before their incubation, the printed samples showed 79.09% antioxidant activity and no antidenaturant capacity was detected. However, after their incubation, the antioxidant activity went down to only 2.50%, while the antidenaturant capacity raised up to 23.50%. The persistence of the bioactive properties after printing opens the possibility of using the functionalized PLA filaments as the feed for a three-dimensional (3D) printer.

scholarly journals Foundation Piles—A New Feature for Concrete 3D Printers

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2545
Author(s):  
Marcin Hoffmann ◽  
Krzysztof Żarkiewicz ◽  
Adam Zieliński ◽  
Szymon Skibicki ◽  
Łukasz Marchewka
Keyword(s):  
3D Printing ◽  
Rapid Development ◽  
Construction Materials ◽  
Shallow Foundation ◽  
Soil Reinforcement ◽  
3D Printer ◽  
Permanent Formwork ◽  
3D Printers ◽  
New Feature ◽  
The Cost

Foundation piles that are made by concrete 3D printers constitute a new alternative way of founding buildings constructed using incremental technology. We are currently observing very rapid development of incremental technology for the construction industry. The systems that are used for 3D printing with the application of construction materials make it possible to form permanent formwork for strip foundations, construct load-bearing walls and partition walls, and prefabricate elements, such as stairs, lintels, and ceilings. 3D printing systems do not offer soil reinforcement by making piles. The paper presents the possibility of making concrete foundation piles in laboratory conditions using a concrete 3D printer. The paper shows the tools and procedure for pile pumping. An experiment for measuring pile bearing capacity is described and an example of a pile deployment model under a foundation is described. The results of the tests and analytical calculations have shown that the displacement piles demonstrate less settlement when compared to the analysed shallow foundation. The authors indicate that it is possible to replace the shallow foundation with a series of piles combined with a printed wall without locally widening it. This type of foundation can be used for the foundation of low-rise buildings, such as detached houses. Estimated calculations have shown that the possibility of making foundation piles by a 3D printer will reduce the cost of making foundations by shortening the time of execution of works and reducing the consumption of construction materials.

scholarly journals Recent Advances in Myoelectric Control for Finger Prostheses for Multiple Finger Loss

2021 ◽  
Vol 11 (10) ◽  
pp. 4464
Author(s):  
Viritpon Srimaneepong ◽  
Artak Heboyan ◽  
Azeem Ul Yaqin Syed ◽  
Hai Anh Trinh ◽  
Pokpong Amornvit ◽  
...  
Keyword(s):  
Web Of Science ◽  
Myoelectric Control ◽  
Original Research ◽  
Prosthetic Hand ◽  
Precise Control ◽  
Prosthetic Hands ◽  
Prosthesis Retention ◽  
Finger Prosthesis ◽  
Artificial Hand

The loss of one or multiple fingers can lead to psychological problems as well as functional impairment. Various options exist for replacement and restoration after hand or finger loss. Prosthetic hand or finger prostheses improve esthetic outcomes and the quality of life for patients. Myoelectrically controlled hand prostheses have been used to attempt to produce different movements. The available articles (original research articles and review articles) on myoelectrically controlled finger/hand prostheses from January 1922 to February 2021 in English were reviewed using MEDLINE/PubMed, Web of Science, and ScienceDirect resources. The articles were searched using the keywords “finger/hand loss”, “finger prosthesis”, “myoelectric control”, and “prostheses” and relevant articles were selected. Myoelectric or electromyography (EMG) signals are read by myoelectrodes and the signals are amplified, from which the muscle’s naturally generated electricity can be measured. The control of the myoelectric (prosthetic) hands or fingers is important for artificial hand or finger movement; however, the precise control of prosthetic hands or fingers remains a problem. Rehabilitation after multiple finger loss is challenging. Implants in finger prostheses after multiple finger loss offer better finger prosthesis retention. This article presents an overview of myoelectric control regarding finger prosthesis for patients with finger implants following multiple finger loss.

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