scholarly journals Proof of concept of a novel combined consolidation and transfer mechanism for electrophotographic 3D printing

2018 ◽  
Vol 24 (6) ◽  
pp. 1040-1048 ◽  
Author(s):  
Matthew James Benning ◽  
Kenny Dalgarno
Keyword(s):  
3D Printing ◽  
High Speed ◽  
Transfer Mechanism ◽  
Proof Of Concept ◽  
Content Type ◽  
New Information ◽  
Underlying Causes ◽  
Printing System ◽  
Multiple Materials ◽  
Electrophotographic Printing

Purpose This paper aims to develop and then evaluate a novel consolidation and powder transfer mechanism for electrophotographic 3D printing, designed to overcome two longstanding limitations of electrophotographic 3D printing: fringing and a build height limitation. Design/methodology/approach Analysis of the electric field generated within electrophotographic printing was used to identify the underlying causes of the fringing and build height limitations. A prototype machine was then designed and manufactured to overcome these limitations, and a number of print runs were carried out as proof of concept studies. Findings The analysis suggested that a machine design which separated the electrostatic powder deposition of the print engine from the layer transfer and consolidation steps is required to overcome fringing and build height limitations. A machine with this build architecture was developed and proof of concept studies showed that the build height and fringing effects were no longer evident. Research limitations/implications Electrophotography (EP) was initially seen as a promising technology for 3D printing, largely because the potential for multi-material printing at high speed. As these limitations can now be overcome, there is still potential for EP to deliver a high-speed 3D printing system which can build parts consisting of multiple materials. Originality/value The analysis of EP, the new method for the transfer and consolidation of layers and the proof of concept study are all original and provide new information on how EP can be adopted for 3D printing.

scholarly journals A review of 3D printing processes and materials for soft robotics

2020 ◽  
Vol 26 (8) ◽  
pp. 1345-1361 ◽  
Author(s):  
Yee Ling Yap ◽  
Swee Leong Sing ◽  
Wai Yee Yeong
Keyword(s):  
3D Printing ◽  
Soft Robotics ◽  
Soft Robots ◽  
Content Type ◽  
Advantages And Disadvantages ◽  
The Future ◽  
3D Printed ◽  
Multiple Materials ◽  
Printing Processes ◽  
Printing Techniques

Purpose Soft robotics is currently a rapidly growing new field of robotics whereby the robots are fundamentally soft and elastically deformable. Fabrication of soft robots is currently challenging and highly time- and labor-intensive. Recent advancements in three-dimensional (3D) printing of soft materials and multi-materials have become the key to enable direct manufacturing of soft robots with sophisticated designs and functions. Hence, this paper aims to review the current 3D printing processes and materials for soft robotics applications, as well as the potentials of 3D printing technologies on 3D printed soft robotics. Design/methodology/approach The paper reviews the polymer 3D printing techniques and materials that have been used for the development of soft robotics. Current challenges to adopting 3D printing for soft robotics are also discussed. Next, the potentials of 3D printing technologies and the future outlooks of 3D printed soft robotics are presented. Findings This paper reviews five different 3D printing techniques and commonly used materials. The advantages and disadvantages of each technique for the soft robotic application are evaluated. The typical designs and geometries used by each technique are also summarized. There is an increasing trend of printing shape memory polymers, as well as multiple materials simultaneously using direct ink writing and material jetting techniques to produce robotics with varying stiffness values that range from intrinsically soft and highly compliant to rigid polymers. Although the recent work is done is still limited to experimentation and prototyping of 3D printed soft robotics, additive manufacturing could ultimately be used for the end-use and production of soft robotics. Originality/value The paper provides the current trend of how 3D printing techniques and materials are used particularly in the soft robotics application. The potentials of 3D printing technology on the soft robotic applications and the future outlooks of 3D printed soft robotics are also presented.

The impact of order imbalance on returns, liquidity, and volatility in agricultural commodity markets

2018 ◽  
Vol 78 (5) ◽  
pp. 571-591 ◽  
Author(s):  
Steffen Volkenand ◽  
Guenther Filler ◽  
Martin Odening
Keyword(s):  
Trading Volume ◽  
High Speed ◽  
Price Volatility ◽  
Agricultural Commodity ◽  
Content Type ◽  
Order Imbalance ◽  
New Information ◽  
Agricultural Futures ◽  
Best Offer ◽  
The Impact

PurposeThe purpose of this paper is to investigate and compare the impact of order imbalance on returns, liquidity and price volatility in agricultural futures markets on an intraday basis. The authors examine whether order imbalance is more powerful to explain variations in asset prices compared to other indicators of trading activity, particularly trading volume.Design/methodology/approachUsing Chicago Mercantile Exchange best bid best offer data, the impact of order imbalance is analyzed via regression analyses. The analyses are carried out for corn, wheat, soy, live cattle and lean hogs in March 2008 and March 2016.FindingsResults confirm the positive relation between order imbalance and returns as well as between order imbalance and price volatility as suggested by market microstructure models. Order imbalance, however, does not generally outperform trading volume as an explanatory variable.Practical implicationsFor some contracts, returns can be predicted using lagged order imbalance. This offers the opportunity to derive profitable trading strategies.Originality/valueThis paper is one of the first attempts to explore the relationship between order imbalance and returns, liquidity and volatility for agricultural commodity futures on an intraday basis, accounting for the increased trading volume and for the high speed at which new information enters the market in an electronic trading environment.

scholarly journals Additive manufacturing of powder components based on subtractive sintering approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Maricruz Henkel Carrillo ◽  
Geuntak Lee ◽  
Charles Maniere ◽  
Eugene A. Olevsky
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Ceramic Powder ◽  
High Density ◽  
Ease Of Use ◽  
Powder Particle Size ◽  
Proof Of Concept ◽  
Content Type ◽  
Novel Approach ◽  
Metallic Parts

Purpose The purpose of this work is to introduce a novel approach of using additive manufacturing (AM) to produce dense complex ceramic and metallic parts. Powder 3D printing has been gaining popularity due to its ease of use and versatility. However, powder-based methods such as Selective Laser Melting (SLM) and Sintering (SLS), utilizes high power lasers which generate thermal shock conditions in metals and are not ideal for ceramics due to their high melting temperature. Indirect additive manufacturing methods have been explored to address the above issues but have proven to be wasteful and time-consuming. Design/methodology/approach In this work, a novel approach of producing high density net-shaped prototypes using subtractive sintering (SS) and solvent jetting is developed. AM combined with SS (AM-SS) is a process that includes five simple steps. AM-SS can produce repeatable and reliable results as has been shown in this work. Findings As a proof-of-concept, a zirconia dental crown with a high density of 97% is fabricated using this approach. Microstructure and properties of the fabricated components are analyzed. Originality/value A major advantage of this method is the ability to efficiently fabricate high density parts using either metal powder and more importantly, ceramic powder which is traditionally difficult to densify using AM. Additionally, any powder particle size (including nano) and shape can be used which is not the case for traditional powder-based 3D printing.

scholarly journals Microfluidics by Additive Manufacturing for Wearable Biosensors: A Review

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4236 ◽  
Author(s):  
Mahshid Padash ◽  
Christian Enz ◽  
Sandro Carrara
Keyword(s):  
3D Printing ◽  
Remote Monitoring ◽  
High Speed ◽  
Medical Information ◽  
Academic Research ◽  
Wearable Devices ◽  
Previous Method ◽  
Diabetic Patients ◽  
Microfluidic Systems ◽  
Multiple Materials

Wearable devices are nowadays at the edge-front in both academic research as well as in industry, and several wearable devices have been already introduced in the market. One of the most recent advancements in wearable technologies for biosensing is in the area of the remote monitoring of human health by detection on-the-skin. However, almost all the wearable devices present in the market nowadays are still providing information not related to human ‘metabolites and/or disease’ biomarkers, excluding the well-known case of the continuous monitoring of glucose in diabetic patients. Moreover, even in this last case, the glycaemic level is acquired under-the-skin and not on-the-skin. On the other hand, it has been proven that human sweat is very rich in molecules and other biomarkers (e.g., ions), which makes sweat a quite interesting human liquid with regards to gathering medical information at the molecular level in a totally non-invasive manner. Of course, a proper collection of sweat as it is emerging on top of the skin is required to correctly convey such liquid to the molecular biosensors on board of the wearable system. Microfluidic systems have efficiently come to the aid of wearable sensors, in this case. These devices were originally built using methods such as photolithographic and chemical etching techniques with rigid materials. Nowadays, fabrication methods of microfluidic systems are moving towards three-dimensional (3D) printing methods. These methods overcome some of the limitations of the previous method, including expensiveness and non-flexibility. The 3D printing methods have a high speed and according to the application, can control the textures and mechanical properties of an object by using multiple materials in a cheaper way. Therefore, the aim of this paper is to review all the most recent advancements in the methods for 3D printing to fabricate wearable fluidics and provide a critical frame for the future developments of a wearable device for the remote monitoring of the human metabolism directly on-the-skin.

Study on driving waveform design process for multi-nozzle piezoelectric printhead in material-jetting 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yih-Lin Cheng ◽  
Tzu-Wei Tseng
Keyword(s):  
3D Printing ◽  
Design Process ◽  
High Speed ◽  
Hold Time ◽  
Maximum Velocity ◽  
Waveform Design ◽  
Droplet Velocity ◽  
Content Type ◽  
Satellite Drops ◽  
Driving Waveform

Purpose Material-jetting (MJ) three-dimensional (3D) printing processes are competitive due to their printing resolution and printing speed. Driving waveform design of piezoelectric printhead in MJ would affect droplet formation and performance, but there are very limited studies on it besides patents and know-hows by commercial manufacturers. Therefore, in this research, the waveform design process to efficiently attain suitable parameters for a multi-nozzle piezoelectric printhead was studied. Therefore, this research aims to study the waveform design process to efficiently attain suitable parameters for a multi-nozzle piezoelectric printhead. Design/methodology/approach Ricoh’s Gen4L printhead was adopted. A high-speed camera captured pictures of jetted droplets and droplet velocity was calculated. The waveforms included single-, double- and triple-pulse trapezoidal patterns. The effects of parameters were investigated and the suitable ones were determined based on the avoidance of satellite drops and preference of higher droplet velocity. Findings In a single-pulse waveform, an increase of fill time (Tf) decreased the droplet velocity. The maximum velocity happened at the same pulse width, the sum of fill time and hold time (Tf + Th). In double- and triple-pulse, a voltage difference (Vd) above zero in the holding stage was adopted except the last pulse to avoid satellite drops. Suitable parameters for the selected resin were obtained and the time-saving design process was established. Research limitations/implications Based on the effects of parameters and observed data trends, suggested procedures to determine suitable parameters were proposed with fewer experiments. Practical implications This study has verified the feasibility of suggested design procedures on another resin. The required number of trials was reduced significantly. Originality/value This research investigated the process of driving waveform design for the multi-nozzle piezoelectric printhead. The suggested procedures of finding suitable waveform parameters can reduce experimental trials and will be applicable to other MJ 3D printers when new materials are introduced.

Direct-print photopolymerization for 3D printing

2017 ◽  
Vol 23 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Morteza Vatani ◽  
Jae-Won Choi
Keyword(s):  
3D Printing ◽  
Shear Thinning ◽  
Direct Write ◽  
Content Type ◽  
3D Structures ◽  
Standard Guideline ◽  
Original Contribution ◽  
Printing System ◽  
Shape Retention

Purpose This work aims to present a guideline for ink development used in extrusion-based direct-write (DW) (also referred to as direct-print [DP]) technique and combine the extrusion with instant photopolymerization to present a solvent-free DP photopolymerization (DPP) method to fill the gap between 3D printing and printing multi-functional 3D structures. Design/methodology/approach A DP process called DPP was developed by integration of a screw-driven micro-dispenser into XYZ translation stages. The process was equipped with direct photopolymerization to facilitate the creation of 3D structures. The required characteristics of inks used in this technique were simulated through dispersion of fumed silica particles into photocurable resins to transform them into viscoelastic inks. The characterization method of these inks and the required level of shear thinning and thixotropic properties is presented. Findings Shear thinning and thixotropic properties are necessary components of the inks used in DPP process and other DP techniques. These properties are desirable to facilitate printing and filament shape retention. Extrusion of viscoelastic inks out of a nozzle generates a filament capable of retaining its geometry. Likewise, instant photopolymerization of the dispensed filaments prevents deformation due to the weight of filaments or accumulated weight of layers. Originality/value The DPP process with material-reforming methods has been shown, where there remain many shortcomings in realizing a DP-based 3D printing process with instant photopolymerization in existing literature, as well as a standard guideline and material requirements. The suggested method can be extended to develop a new commercial 3D printing system and printable inks to create various functional 3D structures including sensors, actuators and electronics, where nanoparticles are involved for their functionalities. Particularly, an original contribution to the determination of a rheological property of an ink is provided.

3D printing of geopolymer-based concrete for building applications

2020 ◽  
Vol 26 (10) ◽  
pp. 1783-1788
Author(s):  
Asif Ur Rehman ◽  
Vincenzo M. Sglavo
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Modulus Of Rupture ◽  
Content Type ◽  
Wide Range ◽  
Structural Applications ◽  
Jet Printing ◽  
Printing System ◽  
3D Printed ◽  
Alkali Activated

Purpose Three-dimensional (3D) printing technology allows geometric complexity and customization with a significant reduction in the structural environmental impact. Nevertheless, it poses a serious threat to the environment when organic binders are used. Binder jet printing of alkali-activated geopolymer precursor can represent a successful and environmental-friendly alternative. Design/methodology/approach The present work reports about the successful 3D printing of metakaolin-based alkali-activated concrete, with dimensional integrity and valuable mechanical behavior. Findings The geometric behavior was studied as a function of alkali activator flow rate, and the minimum geometric deviation with complete saturation was recorded at 103 mg/s. The printed specimen is characterized by a modulus of rupture as high as 4.4 MPa at 135 mg/s. Practical implications The 3D printed geopolymer-based concrete can be potentially used in a wide range of structural applications from construction to thermal insulation elements. Originality/value The analysis of the 3D geopolymer-based concrete printing system and material conducted in this paper is original.

A chunk-based slicer for cooperative 3D printing

2018 ◽  
Vol 24 (9) ◽  
pp. 1436-1446 ◽  
Author(s):  
Jace McPherson ◽  
Wenchao Zhou
Keyword(s):  
3D Printing ◽  
Future Research ◽  
Large Temperature ◽  
Layer By Layer ◽  
New Approach ◽  
Content Type ◽  
Working Together ◽  
3D Printers ◽  
Multiple Materials ◽  
Printing Speed

Purpose The purpose of this research is to develop a new slicing scheme for the emerging cooperative three-dimensional (3D) printing platform that has multiple mobile 3D printers working together on one print job. Design/methodology/approach Because the traditional lay-based slicing scheme does not work for cooperative 3D printing, a chunk-based slicing scheme is proposed to split the print job into chunks so that different mobile printers can print different chunks simultaneously without interfering with each other. Findings A chunk-based slicer is developed for two mobile 3D printers to work together cooperatively. A simulator environment is developed to validate the developed slicer, which shows the chunk-based slicer working effectively, and demonstrates the promise of cooperative 3D printing. Research limitations/implications For simplicity, this research only considered the case of two mobile 3D printers working together. Future research is needed for a slicing and scheduling scheme that can work with thousands of mobile 3D printers. Practical implications The research findings in this work demonstrate a new approach to 3D printing. By enabling multiple mobile 3D printers working together, the printing speed can be significantly increased and the printing capability (for multiple materials and multiple components) can be greatly enhanced. Social implications The chunk-based slicing algorithm is critical to the success of cooperative 3D printing, which may enable an autonomous factory equipped with a swarm of autonomous mobile 3D printers and mobile robots for autonomous manufacturing and assembly. Originality/value This work presents a new approach to 3D printing. Instead of printing layer by layer, each mobile 3D printer will print one chunk at a time, which provides the much-needed scalability for 3D printing to print large-sized object and increase the printing speed. The chunk-based approach keeps the 3D printing local and avoids the large temperature gradient and associated internal stress as the size of the print increases.

Influence of ageing treatment on microstructure, mechanical properties and adhesive wear behaviour of 6063 aluminium alloy

2014 ◽  
Vol 66 (4) ◽  
pp. 520-524 ◽  
Author(s):  
Serkan Büyükdoğan ◽  
Süleyman Gündüz ◽  
Mustafa Türkmen
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
High Speed ◽  
Al Alloys ◽  
Wear Behaviour ◽  
Al Alloy ◽  
Strain Ageing ◽  
Content Type ◽  
Static Strain ◽  
Structural Applications

Purpose – The paper aims to provide new observations about static strain ageing in aluminium (Al) alloys which are widely used in structural applications. Design/methodology/approach – The present work aims to provide theoretical and practical information to industries or researchers who may be interested in the effect of static strain ageing on mechanical properties of Al alloys. The data are sorted into the following sections: introduction, materials and experimental procedure, results and discussion and conclusions. Findings – Tensile strength, proof strength (0.2 per cent) and percentage elongation measurement were used to investigate the effect of strain ageing on the mechanical properties. Wear tests were performed by sliding the pin specimens, which were prepared from as-received, solution heat-treated, deformed and undeformed specimens after ageing, on high-speed tool steel (64 HRC). It is concluded that the variations in ageing time improved the strength and wear resistance of the 6063 Al alloy; however, a plastically deformed solution-treated alloy has higher strength and wear resistance than undeformed specimens for different ageing times at 180°C. Practical implications – A very useful source of information for industries using or planning to produce Al alloys. Originality/value – This paper fulfils an identified resource need and offers practical help to the industries.

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