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.

Direct 3D printing of low melting point alloy via adhesion mechanism

2017 ◽  
Vol 23 (3) ◽  
pp. 642-650 ◽  
Author(s):  
Yongze Yu ◽  
Fujun Liu ◽  
Jing Liu
Keyword(s):  
Surface Tension ◽  
Melting Point ◽  
Room Temperature ◽  
High Surface ◽  
Public Attention ◽  
Adhesion Mechanism ◽  
Content Type ◽  
3D Structures ◽  
Direct Printing ◽  
Printing System

Purpose This paper aims to propose a method that can directly print low-melting-point alloy In61Bi26Sn9Ga4 into a variety of macroscopic 3D structures at room temperature via adhesion mechanism. Design/methodology/approach In the first section, the principle of the direct printing system is described. As process parameters and material properties have both geometric and physical significance to printing, the approach the authors take is to study the relationships between key parameters and ultimate printed dimension. The surface tension of the fusible alloy is measured under different temperature ranges. Findings The interaction between the initial standoff distance and the geometry of the first layer is critically important for the adhesion of the liquid metal to the substrate and metal deposition. The characterization of the layer stacking in the direct printing process, stability ranges of the layer thickness and printing speed are also demonstrated. The direct printing system is suitable for making 3D structures with low-melting-point alloy under the summarized range of printing conditions. Social implications This study may arouse big public attention among society. Originality/value This study shows possibilities of manufacturing macroscopic 3D metal objects by continuously depositing molten alloy with low viscosity and high surface tension around room temperature. This study provides a supplement to realize compound printing with metal and nonmetal materials together for building terminal functional devices in a low cost and efficient way.

Chemical modification and printability of shear-thinning hydrogel inks for direct-write 3D printing

Polymer ◽  
2018 ◽  
Vol 152 ◽  
pp. 42-50 ◽  
Author(s):  
Patrick T. Smith ◽  
Amrita Basu ◽  
Abhijit Saha ◽  
Alshakim Nelson
Keyword(s):  
3D Printing ◽  
Chemical Modification ◽  
Shear Thinning ◽  
Direct Write

scholarly journals Development, printability and post-curing studies of formulations of materials resistant to microbial attachment for use in inkjet based 3D printing

2016 ◽  
Vol 22 (5) ◽  
pp. 835-841 ◽  
Author(s):  
Belen Begines ◽  
Andrew L. Hook ◽  
Morgan R. Alexander ◽  
Christopher J. Tuck ◽  
Ricky D. Wildman
Keyword(s):  
3D Printing ◽  
Bacterial Attachment ◽  
Content Type ◽  
3D Structures ◽  
3D Print ◽  
Research Fields ◽  
Biomedical Device ◽  
Z Parameter ◽  
Inkjet Printers ◽  
High Level

Purpose This paper aims to print 3D structures from polymers that resist bacterial attachment by reactive jetting of acrylate monomers. Design/methodology/approach The first step towards printing was ink development. Inks were characterised to carry out an estimation of their potential printability using the Z parameter to predict stable jetting conditions. Printability conditions were optimised for each ink using a Dimatix DMP-2800, which enabled 3D structures to be fabricated. Findings UV photo-initiated polymers, which resist bacterial attachment, were found to be printable using piezo-based inkjet printers. The waveform required for each ink depends on the value of the Z parameter. Once the waveform and the printability parameters were optimised, 3D objects were fabricated. Research limitations/implications This methodology has been confirmed as an effective method to 3D print materials that have been demonstrated to be bacteria resistant. However, ink curing depends on modification of some parameters (such as photoinitiator concentration or UV exposure time) which would result in an improvement of the curing process post jetting. Social implications The combination of inkjet based 3D printing with new materials resistant to bacterial attachment means the possibility of building customised medical devices with a high level of complexity and bespoke features can be fully realised. The scope and variability of the devices produced will exceed what can be achieved using standard fabrication methodologies and can be applied to reduce the incidence of device associated infections and to address increased morbidity, mortality and health care costs associated with nosocomial infections. Originality/value In this paper, the novel use of materials that resist bacterial attachment has been described to build 3D structures using material jetting. Its value lies on the potential impact this methodology could produce in the biomedical device and research fields.

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.

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.

Inkjet and inkjet-based 3D printing: connecting fluid properties and printing performance

2017 ◽  
Vol 23 (3) ◽  
pp. 562-576 ◽  
Author(s):  
Yang Guo ◽  
Huseini S. Patanwala ◽  
Brice Bognet ◽  
Anson W.K. Ma
Keyword(s):  
3D Printing ◽  
Flexible Electronics ◽  
Inkjet Printing ◽  
Three Dimensional ◽  
Functional Materials ◽  
Shear Thinning ◽  
Theoretical Understanding ◽  
Content Type ◽  
Shear Thinning Fluids ◽  
Fluid Properties

Purpose This paper aims to summarize the latest developments both in terms of theoretical understanding and experimental techniques related to inkjet fluids. The purpose is to provide practitioners a self-contained review of how the performance of inkjet and inkjet-based three-dimensional (3D) printing is fundamentally influenced by the properties of inkjet fluids. Design/methodology/approach This paper is written for practitioners who may not be familiar with the underlying physics of inkjet printing. The paper thus begins with a brief review of basic concepts in inkjet fluid characterization and the relevant dimensionless groups. Then, how drop impact and contact angle affect the footprint and resolution of inkjet printing is reviewed, especially onto powder and fabrics that are relevant to 3D printing and flexible electronics applications. A future outlook is given at the end of this review paper. Findings The jettability of Newtonian fluids is well-studied and has been generalized using a dimensionless Ohnesorge number. However, the inclusion of various functional materials may modify the ink fluid properties, leading to non-Newtonian behavior, such as shear thinning and elasticity. This paper discusses the current understanding of common inkjet fluids, such as particle suspensions, shear-thinning fluids and viscoelastic fluids. Originality/value A number of excellent review papers on the applications of inkjet and inkjet-based 3D printing already exist. This paper focuses on highlighting the current scientific understanding and possible future directions.

scholarly journals Evaluation of the Ability to Accurately Produce Angular Details by 3D Printing of Plastic Parts

Machines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 150
Author(s):  
Andrei Marius Mihalache ◽  
Gheorghe Nagîț ◽  
Laurențiu Slătineanu ◽  
Adelina Hrițuc ◽  
Angelos Markopoulos ◽  
...  
Keyword(s):  
3D Printing ◽  
Point Of View ◽  
Vertex Angle ◽  
Function Type ◽  
Constant Height ◽  
3D Printers ◽  
3D Printed ◽  
Mathematical Processing ◽  
Plastic Parts

3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of actions and the intensity of the influence exerted by the input factors. It is concluded that the strongest influence on the printer’s ability to produce fine detail, from the point of view addressed in the paper, is exerted by the vertex angle, whose reduction leads to a decrease in printing accuracy.

scholarly journals 3D printing system for earth-based construction: Case study of cob

2021 ◽  
Vol 124 ◽  
pp. 103577
Author(s):  
Mohamed Gomaa ◽  
Wassim Jabi ◽  
Alejandro Veliz Reyes ◽  
Veronica Soebarto
Keyword(s):  
3D Printing ◽  
Printing System
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