scholarly journals Optimized Zirconia 3D Printing Using Digital Light Processing with Continuous Film Supply and a Recyclable Slurry System

2021 ◽  
Author(s):  
Waqas Ahmed Sarwar ◽  
Jin-Ho Kang ◽  
Hyung-In Yoon
Keyword(s):  
Computer Aided Design ◽  
Tape Casting ◽  
High Viscosity ◽  
Solid Loading ◽  
Layer By Layer ◽  
Post Processing ◽  
Continuous Film ◽  
Digital Light Processing ◽  
Ceramic Slurry ◽  
Subtractive Machining

Additive manufacturing (AM) processes, including stereolithography (SL), can fabricate complex ceramic parts layer by layer using computer-aided design (CAD) models. A ceramic slurry with high solid loading is usually used in SL to fabricate the desired shape, which is further sintered to produce the final part. The traditional SL system utilizes a tank filled with printable material, known as a vat, which for ceramic slurry contributes several limitations and operational difficulties, and further renders it non-recyclable mainly due to its high viscosity and the fragility of the green state. In this study, we utilized a continuous film supply (CFS) printer integrated with a tape casting system using in-house-designed ceramic slurry to print standard prototype specimens. Various printing parameters, including viscosity, layer thickness control, and slurry recycling efficiency, were studied. In addition, post-processing optimizations of the prototype, characterizations, and the microhardness of sintered samples were studied to determine their properties and compare them with traditional methods. The effectiveness of slurry reusability was demonstrated by printing with original and recycled slurry to produce consistent densification of final parts. Post-processing was optimized to achieve a relative sinter density of 99.02% and microhardness of 12.59 GPa. This method provides new opportunities to realize dense complex ceramic features with final properties comparable to those produced by subtractive machining and traditional SL. Furthermore, slurry recycling helps to reduce the overall cost and material consumption.

scholarly journals Optimized Zirconia 3D Printing Using Digital Light Processing with Continuous Film Supply and Recyclable Slurry System

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3446
Author(s):  
Waqas Ahmed Sarwar ◽  
Jin-Ho Kang ◽  
Hyung-In Yoon
Keyword(s):  
Relative Density ◽  
Computer Aided Design ◽  
Tape Casting ◽  
High Viscosity ◽  
Solid Content ◽  
Layer By Layer ◽  
Continuous Film ◽  
Digital Light Processing ◽  
Material Recycling ◽  
Cad Models

Stereolithography (SL) can fabricate complex ceramic parts layer by layer using computer-aided design (CAD) models. The traditional SL system utilizes a vat filled with ceramic slurry with a high solid content, which for ceramics contributes to several limitations and operational difficulties, and further renders it nonrecyclable mainly due to the presence of printed residue and its high viscosity. In this study, we utilized a continuous film supply (CFS) system integrated with a tape-casting type digital light processing (DLP) printer to fabricate zirconia prototypes with a solid content of 45 volume percent (vol.%). Various printing and postprocessing parameters were studied for optimization, to achieve a relative density of 99.02% ± 0.08% with a microhardness of 12.59 ± 0.47 GPa. Slurry reusability was also demonstrated by printing with recycled slurry to produce consistent relative density values in the range of 98.86% ± 0.02% to 98.94% ± 0.03%. This method provides new opportunities for material recycling and the fabrication of dense complex ceramic products, reducing the consumption of the material.

Preparation and Characterization of Different Composition Mg-Cu Tapes

2010 ◽  
Vol 434-435 ◽  
pp. 518-521
Author(s):  
Jun Li ◽  
Guo Qiang Luo ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
High Stability ◽  
Tape Casting ◽  
Casting Process ◽  
Solid Loading ◽  
Post Processing ◽  
Processing Stage ◽  
Graded Materials ◽  
Sufficient Strength ◽  
Different Thickness

Tape casting was used for the preparation of Mg-Cu systems density graded materials. A series of tapes with uniform compositions ranging from 100wt% Cu to 100wt% Mg were fabricated with sufficient strength to be handled during the post-processing stage. The effect of the tape casting process parameters on the properties of the tape were studied, such as the composition of the Mg-Cu and the solid loading. The rheology of the slurry of different Mg-Cu composition for tape casting was characterized by viscosity. The tapes characterized by microstructure, thickness and bulk density were outlined. The results demonstrated that the different Mg-Cu composition slurry with well-dispersed, high stability, certain solid loading from 45 ~70 wt% were obtained. The viscosity of the slurry and the density of the green tapes were increased with the increasing of the content of Mg. The thickness of tapes of compositions ranging from 100wt% Cu to 100wt% Mg with certain strength could be achieved 68-110μm and the density of the tapes was 0.74-2.42g/cm3. For 100wt% Cu tapes, when the solid loading was 68wt%, the high density tape was produced. The tapes with different thickness, density and different Mg-Cu compositions were obtained.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

scholarly journals Folding photopolymerized origami sheets by post-curing

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaodong He ◽  
Christopher-Denny Matte ◽  
Tsz-Ho Kwok
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Principal Stress ◽  
Second Step ◽  
Post Processing ◽  
Element Analysis ◽  
Digital Light Processing ◽  
Processing Step ◽  
Lower Maximum

AbstractThe paper presents a novel manufacturing approach to fabricate origami based on 3D printing utilizing digital light processing. Specifically, we propose to leave part of the model uncured during the printing step, and then cure it in the post-processing step to set the shape in a folded configuration. While the cured regions in the first step try to regain their unfolded shape, the regions cured in the second step attempt to keep their folded shape. As a result, the final shape is obtained when both regions’ stresses reach equilibrium. Finite element analysis is performed in ANSYS to obtain the stress distribution on common hinge designs, demonstrating that the square-hinge has a lower maximum principal stress than elliptical and triangle hinges. Based on the square-hinge and rectangular cavity, two variables—the hinge width and the cavity height—are selected as principal variables to construct an empirical model with the final folding angle. In the end, experimental verification shows that the developed method is valid and reliable to realize the proposed deformation and 3D development of 2D hinges.

scholarly journals Metallization of Thermoplastic Polymers and Composites 3D Printed by Fused Filament Fabrication

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Paolo Tralli ◽  
Stefano Turri ◽  
Marinella Levi ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Test Sample ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Post Processing ◽  
Thermoplastic Polymers ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
3D Printed ◽  
Manufacturing Technologies

Fused filament fabrication allows the direct manufacturing of customized and complex products although the layer-by-layer appearance of this process strongly affects the surface quality of the final parts. In recent years, an increasing number of post-processing treatments has been developed for the most used materials. Contrarily to other additive manufacturing technologies, metallization is not a common surface treatment for this process despite the increasing range of high-performing 3D printable materials. The objective of this work is to explore the use of physical vapor deposition sputtering for the chromium metallization of thermoplastic polymers and composites obtained by fused filament fabrication. The thermal and mechanical properties of five materials were firstly evaluated by means of differential scanning calorimetry and tensile tests. Meanwhile, a specific finishing torture test sample was designed and 3D printed to perform the metallization process and evaluate the finishing on different geometrical features. Furthermore, the roughness of the samples was measured before and after the metallization, and a cost analysis was performed to assess the cost-efficiency. To sum up, the metallization of five samples made with different materials was successfully achieved. Although some 3D printing defects worsened after the post-processing treatment, good homogeneity on the finest details was reached. These promising results may encourage further experimentations as well as the development of new applications, i.e., for the automotive and furniture fields.

The role of robotics in additive manufacturing: review of the AM processes and introduction of an intelligent system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
J. Norberto Pires ◽  
Amin S. Azar ◽  
Filipe Nogueira ◽  
Carlos Ye Zhu ◽  
Ricardo Branco ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Intelligent System ◽  
Material Selection ◽  
High Strength Steels ◽  
Industrial Applications ◽  
Layer By Layer ◽  
Content Type ◽  
Functional Components

Purpose Additive manufacturing (AM) is a rapidly evolving manufacturing process, which refers to a set of technologies that add materials layer-by-layer to create functional components. AM technologies have received an enormous attention from both academia and industry, and they are being successfully used in various applications, such as rapid prototyping, tooling, direct manufacturing and repair, among others. AM does not necessarily imply building parts, as it also refers to innovation in materials, system and part designs, novel combination of properties and interplay between systems and materials. The most exciting features of AM are related to the development of radically new systems and materials that can be used in advanced products with the aim of reducing costs, manufacturing difficulties, weight, waste and energy consumption. It is essential to develop an advanced production system that assists the user through the process, from the computer-aided design model to functional components. The challenges faced in the research and development and operational phase of producing those parts include requiring the capacity to simulate and observe the building process and, more importantly, being able to introduce the production changes in a real-time fashion. This paper aims to review the role of robotics in various AM technologies to underline its importance, followed by an introduction of a novel and intelligent system for directed energy deposition (DED) technology. Design/methodology/approach AM presents intrinsic advantages when compared to the conventional processes. Nevertheless, its industrial integration remains as a challenge due to equipment and process complexities. DED technologies are among the most sophisticated concepts that have the potential of transforming the current material processing practices. Findings The objective of this paper is identifying the fundamental features of an intelligent DED platform, capable of handling the science and operational aspects of the advanced AM applications. Consequently, we introduce and discuss a novel robotic AM system, designed for processing metals and alloys such as aluminium alloys, high-strength steels, stainless steels, titanium alloys, magnesium alloys, nickel-based superalloys and other metallic alloys for various applications. A few demonstrators are presented and briefly discussed, to present the usefulness of the introduced system and underlying concept. The main design objective of the presented intelligent robotic AM system is to implement a design-and-produce strategy. This means that the system should allow the user to focus on the knowledge-based tasks, e.g. the tasks of designing the part, material selection, simulating the deposition process and anticipating the metallurgical properties of the final part, as the rest would be handled automatically. Research limitations/implications This paper reviews a few AM technologies, where robotics is a central part of the process, such as vat photopolymerization, material jetting, binder jetting, material extrusion, powder bed fusion, DED and sheet lamination. This paper aims to influence the development of robot-based AM systems for industrial applications such as part production, automotive, medical, aerospace and defence sectors. Originality/value The presented intelligent system is an original development that is designed and built by the co-authors J. Norberto Pires, Amin S. Azar and Trayana Tankova.

Constraints and limitations of concrete 3D printing in architecture

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chien-Ho Ko
Keyword(s):  
3D Printing ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Research Approach ◽  
Layer By Layer ◽  
Content Type ◽  
Improve Design ◽  
Study Results ◽  
Computer Aided ◽  
Property Control

Purpose Additive manufacturing of concrete (AMoC) is an emerging technology for constructing buildings. However, due to the nature of the concrete property and constructing buildings in layers, constraints and limitations are encountered while applying AMoC in architecture. This paper aims to analyze the constraints and limitations that may be encountered while using AMoC in architecture. Design/methodology/approach A descriptive research approach is used to conduct this study. First, basic notions of AMoC are introduced. Then, challenges of AMoC, including hardware, material property, control and design, are addressed. Finally, strategies that may be used to overcome the challenges are discussed. Findings Factors influencing the success of AMoC include hardware, material, control methods, manufacturing process and design. Considering these issues in the early design phase is crucial to achieving a successful computer-aided design (CAD)/computer-aided manufacturing (CAM) integration to bring CAD and CAM benefits into the architecture industry. Originality/value In three-dimensional (3D) printing, objects are constructed layer by layer. Printing results are thus affected by the additive method (such as toolpath) and material properties (such as tensile strength and slump). Although previous studies attempt to improve AMoC, most of them focus on the manufacturing process. However, a successful application of AMoC in architecture needs to consider the possible constraints and limitations of concrete 3D printing. So far, research on the potential challenges of applying AMoC in architecture from a building lifecycle perspective is still limited. The study results of this study could be used to improve design and construction while applying AMoC in architecture.

An oriented feature extraction and recognition approach for concave-convex mixed interacting features in cast-then-machined parts

2018 ◽  
Vol 233 (4) ◽  
pp. 1269-1288 ◽  
Author(s):  
Haichao Wang ◽  
Jie Zhang ◽  
Xiaolong Zhang ◽  
Changwei Ren ◽  
Xiaoxi Wang ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Computer Aided Design ◽  
Feature Recognition ◽  
Freeform Surface ◽  
Layer By Layer ◽  
Computer Aided Process Planning ◽  
Computer Aided ◽  
Machined Parts ◽  
Aided Design ◽  
Interacting Features

Feature recognition is an important technology of computer-aided design/computer-aided engineering/computer-aided process planning/computer-aided manufacturing integration in cast-then-machined part manufacturing. Graph-based approach is one of the most popular feature recognition methods; however, it cannot still solve concave-convex mixed interacting feature recognition problem, which is a common problem in feature recognition of cast-then-machined parts. In this study, an oriented feature extraction and recognition approach is proposed for concave-convex mixed interacting features. The method first extracts predefined features directionally according to the rules generated from attributed adjacency graphs–based feature library and peels off them from part model layer by layer. Sub-features in an interacting feature are associated via hints and organized as a feature tree. The time cost is reduced to less than [Formula: see text] by eliminating subgraph isomorphism and matching operations. Oriented feature extraction and recognition approach recognizes non-freeform-surface features directionally regardless of the part structure. Hence, its application scope can be extended to multiple kinds of non-freeform-surface parts by customizing. Based on our findings, implementations on prismatic, plate, fork, axlebox, linkage, and cast-then-machined parts prove that the proposed approach is applicable on non-freeform-surface parts and effectively recognize concave-convex mixed interacting feature in various mechanical parts.

scholarly journals The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2304 ◽  
Author(s):  
Janusz Kluczyński ◽  
Lucjan Śnieżek ◽  
Krzysztof Grzelak ◽  
Janusz Mierzyński
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Final Analysis ◽  
Machine Building ◽  
Layer By Layer ◽  
Laser Melting ◽  
Measurement Results ◽  
Computer Aided ◽  
Exposure Energy ◽  
Aided Design

Selective laser melting (SLM) is an additive manufacturing technique. It allows elements with very complex geometry to be produced using metallic powders. A geometry of manufacturing elements is based only on 3D computer-aided design (CAD) data. The metal powder is melted selectively layer by layer using an ytterbium laser. This paper contains the results of porosity and microhardness analysis made on specimens manufactured during a specially prepared process. Final analysis helped to discover connections between changing hatching distance, exposure speed and porosity. There were no significant differences in microhardness and porosity measurement results in the planes perpendicular and parallel to the machine building platform surface.

Carbon Nanotube Reinforced Fused Deposition Modeling Using Microwave Irradiation

2016 ◽  
Author(s):  
Meng Zhang ◽  
Xiaoxu Song ◽  
Weston Grove ◽  
Emmett Hull ◽  
Z. J. Pei ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Additive Manufacturing ◽  
Microwave Irradiation ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Layer By Layer ◽  
Sem Images ◽  
Fused Deposition ◽  
Deposition Modeling

Additive manufacturing (AM) is a class of manufacturing processes where material is deposited in a layer-by-layer fashion to fabricate a three-dimensional part directly from a computer-aided design model. With a current market share of 44%, thermoplastic-based additive manufacturing such as fused deposition modeling (FDM) is a prevailing technology. A key challenge for AM parts (especially for parts made by FDM) in engineering applications is the weak inter-layer adhesion. The lack of bonding between filaments usually results in delamination and mechanical failure. To address this challenge, this study embedded carbon nanotubes into acrylonitrile butadiene styrene (ABS) thermoplastics via a filament extrusion process. The vigorous response of carbon nanotubes to microwave irradiation, leading to the release of a large amount of heat, is used to melt the ABS thermoplastic matrix adjacent to carbon nanotubes within a very short time period. This treatment is found to enhance the inter-layer adhesion without bulk heating to deform the 3D printed parts. Tensile and flexural tests were performed to evaluation the effects of microwave irradiation on mechanical properties of the specimens made by FDM. Scanning electron microscopic (SEM) images were taken to characterize the fracture surfaces of tensile test specimens. The actual carbon nanotube contents in the filaments were measured by conducting thermogravimetric analysis (TGA). The effects of microwave irradiation on the electrical resistivity of the filament were also reported.

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