DESIGN OF A 3D-PRINTED THREE-CLAW ROBOTIC GRIPPER END-EFFECTOR

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.

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Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽

10.1039/d1lc00452b ◽

2021 ◽

Author(s):

Liang Wu ◽

Stephen Beirne ◽

Joan-Marc Cabot Canyelles ◽

Brett Paull ◽

Gordon G. Wallace ◽

...

Keyword(s):

Additive Manufacturing ◽

3D Printing ◽

Polylactic Acid ◽

Fused Filament Fabrication ◽

Flexible Approach ◽

Electroosmotic Pump ◽

3D Printed ◽

Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

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Mechanical Properties of 3D-Printed Wood-Plastic Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.777.499 ◽

2018 ◽

Vol 777 ◽

pp. 499-507 ◽

Cited By ~ 4

Author(s):

Ossi Martikka ◽

Timo Kärki ◽

Qing Ling Wu

Keyword(s):

Mechanical Properties ◽

Composite Materials ◽

3D Printing ◽

Impact Strength ◽

Polylactic Acid ◽

Wood Plastic Composite ◽

Wood Plastic Composites ◽

Plastic Composite ◽

Plastic Composites ◽

3D Printed

3D printing has rapidly become popular in both industry and private use. Especially fused deposition modeling has increased its popularity due to its relatively low cost. The purpose of this study is to increase knowledge in the mechanical properties of parts made of wood-plastic composite materials by using 3D printing. The tensile properties and impact strength of two 3D-printed commercial wood-plastic composite materials are studied and compared to those made of pure polylactic acid. Relative to weight –mechanical properties and the effect of the amount of fill on the properties are also determined. The results indicate that parts made of wood-plastic composites have notably lower tensile strength and impact strength that those made of pure polylactic acid. The mechanical properties can be considered sufficient for low-stress applications, such as visualization of prototypes and models or decorative items.

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Enhancement of the Compressive Strength of 3D-Printed Polylactic Acid(PLA) by Controlling Internal Pattern

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1023.75 ◽

2021 ◽

Vol 1023 ◽

pp. 75-81

Author(s):

Aappo Mustakangas ◽

Atef Hamada ◽

Antti Järvenpää

Keyword(s):

Compressive Strength ◽

3D Printing ◽

Polylactic Acid ◽

Optical Microscope ◽

Fused Filament Fabrication ◽

Loading Direction ◽

Compressive Flow ◽

3D Printed ◽

Cost Efficient ◽

Loading Axis

Cost-efficient 3D-printing can create a lot of new opportunities in engineering as it enables rapid prototyping of models and functional parts. In the present study, Polylactic acid (PLA) cubic specimens with different types of infill patterns (IPs), rectilinear, grid and cuboid, were additively manufactured by Fused Filament Fabrication 3D-printing. The PLA cubes are fabricated with one perimeter and different IPs density (10, 20, and 30%). Subsequently, the compressive strengths of the PLA materials were measured in two loading directions, i.e., the layers building direction is parallel (PD) to the loading axis and perpendicular (ND) to the loading direction. An optical microscope was used to examine the deformed IPs in both loading directions. The compressive flow stress curves of the PLA cubes infilled with rectilinear and grid patterns exhibited strong fluctuations with lower compressive strengths in the loading direction along ND. The PLA with 30% grid IP revealed a superior strength of ~12 kN in the loading direction along PD. On the contrary, the same material exhibited a worst compressive strength 3 kN along ND.

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Electrospinning on 3D Printed Polymers for Mechanically Stabilized Filter Composites

Polymers ◽

10.3390/polym11122034 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2034 ◽

Cited By ~ 10

Author(s):

Tomasz Kozior ◽

Al Mamun ◽

Marah Trabelsi ◽

Martin Wortmann ◽

Sabantina Lilia ◽

...

Keyword(s):

3D Printing ◽

Thermoplastic Polyurethane ◽

High Surface ◽

Antimicrobial Properties ◽

Mechanical Damage ◽

Volume Ratio ◽

Electrospun Nanofiber ◽

Polymer Nanofiber ◽

3D Printed ◽

Nanofiber Mats

Electrospinning is a frequently used method to prepare air and water filters. Electrospun nanofiber mats can have very small pores, allowing for filtering of even the smallest particles or molecules. In addition, their high surface-to-volume ratio allows for the integration of materials which may additionally treat the filtered material through photo-degradation, possess antimicrobial properties, etc., thus enhancing their applicability. However, the fine nanofiber mats are prone to mechanical damage. Possible solutions include reinforcement by embedding them in composites or gluing them onto layers that are more mechanically stable. In a previous study, we showed that it is generally possible to stabilize electrospun nanofiber mats by 3D printing rigid polymer layers onto them. Since this procedure is not technically easy and needs some experience to avoid delamination as well as damaging the nanofiber mat by the hot nozzle, here we report on the reversed technique (i.e., first 3D printing a rigid scaffold and subsequently electrospinning the nanofiber mat on top of it). We show that, although the adhesion between both materials is insufficient in the case of a common rigid printing polymer, nanofiber mats show strong adhesion to 3D printed scaffolds from thermoplastic polyurethane (TPU). This paves the way to a second approach of combining 3D printing and electrospinning in order to prepare mechanically stable filters with a nanofibrous surface.

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3D printing of biofiber-reinforced composites and their mechanical properties: a review

Rapid Prototyping Journal ◽

10.1108/rpj-08-2019-0214 ◽

2020 ◽

Vol 26 (6) ◽

pp. 1113-1129

Author(s):

Lai Jiang ◽

Xiaobo Peng ◽

Daniel Walczyk

Keyword(s):

Mechanical Properties ◽

3D Printing ◽

Reinforced Composites ◽

Research Directions ◽

Content Type ◽

Reinforced Composite ◽

3D Printed ◽

Materials Used ◽

Printing Processes ◽

Pure Resin

Purpose This paper aims to summarize the up-to-date research performed on combinations of various biofibers and resin systems used in different three-dimensional (3D) printing technologies, including powder-based, material extrusion, solid-sheet and liquid-based systems. Detailed information about each process, including materials used and process design, are described, with the resultant products’ mechanical properties compared with those of 3D-printed parts produced from pure resin or different material combinations. In most processes introduced in this paper, biofibers are beneficial in improving the mechanical properties of 3D-printed parts and the biodegradability of the parts made using these green materials is also greatly improved. However, research on 3D printing of biofiber-reinforced composites is still far from complete, and there are still many further studies and research areas that could be explored in the future. Design/methodology/approach The paper starts with an overview of the current scenario of the composite manufacturing industry and then the problems of advanced composite materials are pointed out, followed by an introduction of biocomposites. The main body of the paper covers literature reviews of recently emerged 3D printing technologies that were applied to biofiber-reinforced composite materials. This part is classified into subsections based on the form of the starting materials used in the 3D printing process. A comprehensive conclusion is drawn at the end of the paper summarizing the findings by the authors. Findings Most of the biofiber-reinforced 3D-printed products exhibited improved mechanical properties than products printed using pure resin, indicating that biofibers are good replacements for synthetic ones. However, synthetic fibers are far from being completely replaced by biofibers due to several of their disadvantages including higher moisture absorbance, lower thermal stability and mechanical properties. Many studies are being performed to solve these problems, yet there are still some 3D printing technologies in which research concerning biofiber-reinforced composite parts is quite limited. This paper unveils potential research directions that would further develop 3D printing in a sustainable manner. Originality/value This paper is a summary of attempts to use biofibers as reinforcements together with different resin systems as the starting material for 3D printing processes, and most of the currently available 3D printing techniques are included herein. All of these attempts are solutions to some principal problems with current 3D printing processes such as the limit in the variety of materials and the poor mechanical performance of 3D printed parts. Various types of biofibers are involved in these studies. This paper unveils potential research directions that would further widen the use of biofibers in 3D printing in a sustainable manner.

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Investigating the Potential of Commercial-Grade Carbon Black-Filled TPU for the 3D Printing of Compressive Sensors

Micromachines ◽

10.3390/mi10010046 ◽

2019 ◽

Vol 10 (1) ◽

pp. 46 ◽

Cited By ~ 1

Author(s):

Claudio Manganiello ◽

David Naso ◽

Francesco Cupertino ◽

Orazio Fiume ◽

Gianluca Percoco

Keyword(s):

3D Printing ◽

Carbon Black ◽

Thermoplastic Polyurethane ◽

Hollow Structure ◽

Soft Or ◽

Commercial Grade ◽

Displacement Sensors ◽

Commercial Carbon ◽

3D Printed ◽

Mechanical Devices

The present research aims to exploit commercially available materials and machines to fabricate multilayer, topologically designed transducers, which can be embedded into mechanical devices, such as soft or rigid grippers. Preliminary tests on the possibility of fabricating 3D-printed transducers using a commercial conductive elastomeric filament, carbon black-filled thermoplastic polyurethane, are presented. The commercial carbon-filled thermoplastic polyurethane (TPU), analyzed in the present paper, has proven to be a candidate material for the production of 3D printed displacement sensors. Some limitations in fabricating the transducers from a 2.85 mm filament were found, and comparisons with 1.75 mm filaments should be conducted. Moreover, further research on the low repeatability at low displacements and the higher performance of the hollow structure, in terms of repeatability, must be carried out. To propose an approach that can very easily be reproduced, only commercial filaments are used.

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The Application of 3D-Printing Techniques in the Manufacturing of Cement-Based Construction Products and Experiences Based on the Assessment of Such Products

Buildings ◽

10.3390/buildings10090144 ◽

2020 ◽

Vol 10 (9) ◽

pp. 144

Author(s):

Guillermo Sotorrío Ortega ◽

Javier Alonso Madrid ◽

Nils O. E. Olsson ◽

José Antonio Tenorio Ríos

Keyword(s):

3D Printing ◽

Construction Industry ◽

Material Consumption ◽

Construction Products ◽

International Projects ◽

Substantial Progress ◽

3D Printed ◽

Materials Used ◽

Printing Techniques

The construction industry has embraced digitisation and industrialisation in response to the need to increase its productivity, optimise material consumption and improve workmanship. Additive manufacturing (AM), more widely known as 3D printing, has driven substantial progress in these respects in other industries, and a number of national and international projects have helped to introduce the technique to the construction industry. As with other innovative processes not covered by uniform standards, appropriate assessments and testing methodologies to control the quality of the 3D-printed end products, while not obligatory, are advisable. This article shows that regulation is not an obstacle to the use of an innovative product, such as 3D printing, by proposing quality-control tests and an assessment methodology, in the understanding that standardisation ensures the viability of a technology. The information, including the methods and results, is based on the authors’ experiences in the development of three research projects pertaining to 3D printing. This paper also discusses whether the performance of the materials used in 3D printing could be superior to traditional ones.

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Ten guidelines for the design of non-assembly mechanisms: The case of 3D-printed prosthetic hands

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411918794734 ◽

2018 ◽

Vol 232 (9) ◽

pp. 962-971 ◽

Cited By ~ 8

Author(s):

Juan Sebastian Cuellar ◽

Gerwin Smit ◽

Amir A Zadpoor ◽

Paul Breedveld

Keyword(s):

Developing Countries ◽

3D Printing ◽

Fused Deposition Modelling ◽

Prosthetic Hand ◽

Prosthetic Devices ◽

Hand Prosthesis ◽

Fused Deposition ◽

Prosthetic Hands ◽

Design Considerations ◽

3D Printed

In developing countries, prosthetic workshops are limited, difficult to reach, or even non-existent. Especially, fabrication of active, multi-articulated, and personalized hand prosthetic devices is often seen as a time-consuming and demanding process. An active prosthetic hand made through the fused deposition modelling technology and fully assembled right after the end of the 3D printing process will increase accessibility of prosthetic devices by reducing or bypassing the current manufacturing and post-processing steps. In this study, an approach for producing active hand prosthesis that could be fabricated fully assembled by fused deposition modelling technology is developed. By presenting a successful case of non-assembly 3D printing, this article defines a list of design considerations that should be followed in order to achieve fully functional non-assembly devices. Ten design considerations for additive manufacturing of non-assembly mechanisms have been proposed and a design case has been successfully addressed resulting in a fully functional prosthetic hand. The hand prosthesis can be 3D printed with an inexpensive fused deposition modelling machine and is capable of performing different types of grasping. The activation force required to start a pinch grasp, the energy required for closing, and the overall mass are significantly lower than body-powered commercial prosthetic hands. The results suggest that this non-assembly design may be a good alternative for amputees in developing countries.

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Simulation and Validation of Fully 3D Printed Soft Actuators

ASME 2020 Conference on Smart Materials, Adaptive Structures and Intelligent Systems ◽

10.1115/smasis2020-2240 ◽

2020 ◽

Author(s):

Steffi Torres ◽

Julio San Martin ◽

Brittany Newell ◽

Jose Garcia

Keyword(s):

3D Printing ◽

Thermoplastic Polyurethane ◽

Pharmaceutical Products ◽

Element Analysis ◽

Strain Behavior ◽

Fea Model ◽

First Case ◽

3D Printed ◽

Soft Actuators ◽

Robotic Applications

Abstract Flexible actuators are a growing class of devices implemented in soft robotic applications, medical devices and processes involving food and pharmaceutical products. Such actuators have traditionally been manufactured using casting processes or other conventional methods requiring more than one fabrication step. The arrival of flexible 3D printing materials and 3D printing techniques has facilitated the creation of these flexible actuators via additive manufacturing. The work presented in this article displays the analytical characterization and experimental validation of two materials and two actuator designs. The first case presents a finite element analysis (FEA) simulated model of a bellows actuator using a photocurable flexible resin (TangoPlus FLX930) and studies the effect of printing orientation on the simulation. The simulation used a 5 parameter Mooney-Rivlin model to predict the strain behavior of the actuator under hydrostatic pressure. A second case is presented where a Thermoplastic Polyurethane actuator was 3D printed and simulated using the same FEA model and a second calibration of the Mooney-Rivlin 5 parameter model. In both cases experimental data was used to calibrate and validate the simulation. The resulting simulated strain was consistent when the printing orientation of actuators was parallel (0 degrees) to the strain direction of the actuators. Results were less consistent when a print orientation of 45 degrees was applied.

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Effect of Porosity and Crystallinity on 3D Printed PLA Properties

Polymers ◽

10.3390/polym11091487 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1487 ◽

Cited By ~ 19

Author(s):

Yuhan Liao ◽

Chang Liu ◽

Bartolomeo Coppola ◽

Giuseppina Barra ◽

Luciano Di Maio ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Additive Manufacturing ◽

3D Printing ◽

Polylactic Acid ◽

Complex Geometry ◽

Fused Filament Fabrication ◽

3D Printed ◽

Physical Changes ◽

Crystalline Forms

Additive manufacturing (AM) is a promising technology for the rapid tooling and fabrication of complex geometry components. Among all AM techniques, fused filament fabrication (FFF) is the most widely used technique for polymers. However, the consistency and properties control of the FFF product remains a challenging issue. This study aims to investigate physical changes during the 3D printing of polylactic acid (PLA). The correlations between the porosity, crystallinity and mechanical properties of the printed parts were studied. Moreover, the effects of the build-platform temperature were investigated. The experimental results confirmed the anisotropy of printed objects due to the occurrence of orientation phenomena during the filament deposition and the formation both of ordered and disordered crystalline forms (α and δ, respectively). A heat treatment post-3D printing was proposed as an effective method to improve mechanical properties by optimizing the crystallinity (transforming the δ form into the α one) and overcoming the anisotropy of the 3D printed object.

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