3D Printing of High Viscosity Reinforced Silicone Elastomers

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.

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Direct Patterning and Spontaneous Self-Assembly of Graphene Oxide via Electrohydrodynamic Jet Printing for Energy Storage and Sensing

Micromachines ◽

10.3390/mi11010013 ◽

2019 ◽

Vol 11 (1) ◽

pp. 13 ◽

Cited By ~ 2

Author(s):

Bin Zhang ◽

Jaehyun Lee ◽

Mincheol Kim ◽

Naeeung Lee ◽

Hyungdong Lee ◽

...

Keyword(s):

Graphene Oxide ◽

Energy Storage ◽

Self Assembly ◽

High Performance ◽

Three Dimensional ◽

Chemical Properties ◽

Layer By Layer ◽

Energy Storage Devices ◽

Laminar Structure ◽

Jet Printing

The macroscopic assembly of two-dimensional materials into a laminar structure has received considerable attention because it improves both the mechanical and chemical properties of the original materials. However, conventional manufacturing methods have certain limitations in that they require a high temperature process, use toxic solvents, and are considerably time consuming. Here, we present a new system for the self-assembly of layer-by-layer (LBL) graphene oxide (GO) via an electrohydrodynamic (EHD) jet printing technique. During printing, the orientation of GO flakes can be controlled by the velocity distribution of liquid jet and electric field-induced alignment spontaneously. Closely-packed GO patterns with an ordered laminar structure can be rapidly realized using an interfacial assembly process on the substrates. The surface roughness and electrical conductivity of the LBL structure were significantly improved compared with conventional dispensing methods. We further applied this technique to fabricate a reduced graphene oxide (r-GO)-based supercapacitor and a three-dimensional (3D) metallic grid hybrid ammonia sensor. We present the EHD-assisted assembly of laminar r-GO structures as a new platform for preparing high-performance energy storage devices and sensors.

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A Review on the Fabrication and Reliability of Three-Dimensional Integration Technologies for Microelectronic Packaging: Through-Si-Via and Solder Bumping Process

Metals ◽

10.3390/met11101664 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1664

Author(s):

Do Hoon Cho ◽

Seong Min Seo ◽

Jang Baeg Kim ◽

Sri Harini Rajendran ◽

Jae Pil Jung

Keyword(s):

High Speed ◽

High Performance ◽

New Technologies ◽

Three Dimensional ◽

High Density ◽

Internal Stresses ◽

Deep Reactive Ion Etching ◽

Fifth Generation ◽

Precise Understanding ◽

Fabrication Defects

With the continuous miniaturization of electronic devices and the upcoming new technologies such as Artificial Intelligence (AI), Internet of Things (IoT), fifth-generation cellular networks (5G), etc., the electronics industry is achieving high-speed, high-performance, and high-density electronic packaging. Three-dimensional (3D) Si-chip stacking using through-Si-via (TSV) and solder bumping processes are the key interconnection technologies that satisfy the former requirements and receive the most attention from the electronic industries. This review mainly includes two directions to get a precise understanding, such as the TSV filling and solder bumping, and explores their reliability aspects. TSV filling addresses the DRIE (deep reactive ion etching) process, including the coating of functional layers on the TSV wall such as an insulating layer, adhesion layer, and seed layer, and TSV filling with molten solder. Solder bumping processes such as electroplating, solder ball bumping, paste printing, and solder injection on a Cu pillar are discussed. In the reliability part for TSV and solder bumping, the fabrication defects, internal stresses, intermetallic compounds, and shear strength are reviewed. These studies aimed to achieve a robust 3D integration technology effectively for future high-density electronics packaging.

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Layer-by-layer self-assembled GO-MoS2Co3O4 three-dimensional conducting network for high-performance supercapacitors

Journal of Energy Storage ◽

10.1016/j.est.2021.103195 ◽

2021 ◽

Vol 43 ◽

pp. 103195

Author(s):

Jie Xu ◽

Jing Liang ◽

Yongjin Zou ◽

Fen Xu ◽

Qiaohong Chen ◽

...

Keyword(s):

High Performance ◽

Three Dimensional ◽

Layer By Layer ◽

Self Assembled

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Graphene oxide/epoxy acrylate nanocomposite production via SLA and importance of graphene oxide surface modification for mechanical properties

Rapid Prototyping Journal ◽

10.1108/rpj-06-2020-0114 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Emrah Uysal ◽

Mustafa Çakir ◽

Bülent Ekici

Keyword(s):

Mechanical Properties ◽

Surface Modification ◽

Graphene Oxide ◽

Three Dimensional ◽

Oxide Nanoparticles ◽

Epoxy Acrylate ◽

Uv Curable ◽

Content Type ◽

Modified Graphene Oxide ◽

Modified Graphene

Purpose Traditional nanocomposite production methods such as in situ polymerization, melt blending and solvent technique, have some deficits. Some of these are non-homogeneous particle distribution, setup difficulties, time-consuming and costly. On the other hand, three-dimensional printing technology is a quite popular method. Especially, Stereolithography (SLA) printing offers some benefits such as fast printing, easy setup and smooth surface specialties. Furthermore, surface modification of Graphene Oxide (GO) and its effects on polymer nanocomposites are quite important. The purpose of this study is to examine the effect of surface modification of GO nanoparticles on the mechanical properties and morphology of epoxy acrylate (BisGMA/1,6 hexane diol diacrylate) matrix nanocomposites. Design/methodology/approach In this study, Ultraviolet (UV) curable end groups of synthesized resin were linked to functional groups of graphene oxide, which are synthesized by the Tour method, which is a kind of modified Hummer method. In addition, synthesized GO nanoparticle’s surfaces were modified by 3-(methacryloyloxy) propyl trimethoxysilane. Significant weight percentages of GO were added into the epoxy acrylate resin. Different Wt.% of modified graphene oxide/acrylate resins was used to print test specimens with SLA type three-dimensional printer. Findings Surface modification has a significant effect on tensile strength for graphene oxide nanoparticles contained composites. In addition, a specific trend was not observed for tensile test results of non-modified graphene oxide. The tendency of impact and hardness test finding were similar for both surfaces modified and non-modified nanoparticles. Finally, the distribution of particles was homogeneous. Originality/value This paper is unique because of the inclusion of both surface modifications of graphene oxide nanoparticles and SLA production of nanocomposites with its own production of three-dimensional printer and photocurable polymer resin.

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Structure, Mechanical Performance, and Dimensional Stability of Radiata Pine (Pinus radiata D. Don) Scrimbers

Advances in Polymer Technology ◽

10.1155/2019/5209624 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8

Author(s):

Jinguang Wei ◽

Fei Rao ◽

Yuxiang Huang ◽

Yahui Zhang ◽

Yue Qi ◽

...

Keyword(s):

Mechanical Properties ◽

Pinus Radiata ◽

Dimensional Stability ◽

High Performance ◽

Water Resistance ◽

Mechanical Performance ◽

Three Dimensional ◽

Radiata Pine ◽

Specific Strength ◽

Shearing Strength

Natural wood has certain advantages such as good processability and high specific strength and thus has been used for millennium as a structural material. But the mechanical performance and water resistance, particularly for fast-growing species, are unsatisfactory for high-end applications. In this study, the “new-type” scrimber technology was introduced to radiata pine (Pinus radiata D. Don) scrimbers. The structure, mechanical properties, and dimensional stability of the scrimber panels were investigated. Results showed that OWFMs as basic units of scrimber had been very even in size and superior permeability. The scrimbers exhibited a three-dimensional porous structure, and the porosity had a decrease with increasing density. Both OWFMs and densification contributed to the high performance in terms of mechanical properties and water resistance. The flexural, compressive, and short-beam shearing strength were significantly enhanced with increasing density. As the density was 0.80 g cm−3, the flexural strength (MOR) was approximately 120 MPa, much larger than many selected wood-based panels. Moreover, the water resistance and dimensional stability also were closely related to the density. At the density of 1.39 g cm−3, the water absorption rate and thinness swelling rate of the panels in boiled water were only 19% and 5.7%, respectively.

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Three-Dimensional Graphite Filled Poly(Vinylidene Fluoride) Composites with Enhanced Strength and Thermal Conductivity

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.842.63 ◽

2020 ◽

Vol 842 ◽

pp. 63-68

Author(s):

Xiao Zhang ◽

Jian Zheng ◽

Yong Qiang Du ◽

Chun Ming Zhang

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Energetic Materials ◽

High Performance ◽

Vinylidene Fluoride ◽

3D Structure ◽

Three Dimensional ◽

3D Network ◽

Poly Vinylidene Fluoride ◽

Polymer Bonded Explosives

Three-dimensional (3D) network structure has been recognized as an efficient approach to enhance the mechanical and thermal conductive properties of polymeric composites. However, it has not been applied in energetic materials. In this work, a fluoropolymer based composite with vertically oriented and interconnected 3D graphite network was fabricated for polymer bonded explosives (PBXs). Here, the graphite and graphene oxide platelets were mixed, and self-assembled via rapid freezing and using crystallized ice as the template. The 3D structure was finally obtained by freezing-dry, and infiltrating with polymer. With the increasing of filler fraction and cooling rate, the thermal conductivity of the polymer composite was significantly improved to 2.15 W m-1 K-1 by 919% than that of pure polymer. Moreover, the mechanical properties, such as tensile strength and elastic modulus, were enhanced by 117% and 563%, respectively, when the highly ordered structure was embedded in the polymer. We attribute the increased thermal and mechanical properties to this 3D network, which is beneficial to the effective heat conduction and force transfer. This study supports a desirable way to fabricate the strong and thermal conductive fluoropolymer composites used for the high-performance polymer bonded explosives (PBXs).

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Enhancing the Capillary Force of Binder-Jetting Printing Ti6Al4V and Mechanical Properties under High Temperature Sintering by Mixing Fine Powder

Metals ◽

10.3390/met10101354 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1354

Author(s):

Yang Tang ◽

Zheguan Huang ◽

Jianming Yang ◽

Yonglin Xie

Keyword(s):

Mechanical Properties ◽

Capillary Force ◽

High Performance ◽

Three Dimensional ◽

Fine Powder ◽

Green Body ◽

Mixed Powder ◽

Powder Bed ◽

Polymer Binders

Binder jet 3D printing (BJ3DP) is an additive manufacturing technology that selectively deposits binder on powder to form a three-dimensional green body followed by sintering process. The low strength of green body and metallurgical issues limit the manufacture of Ti6Al4V parts with high-performance and that are lightweight. In this study, thermal-bubble inkjet technology was used to print Ti6Al4V parts via jetting low-concentration in-situ polymer binders. In addition, a method for mixing fine powder was used to enhance the capillary force of the powder bed and mechanical properties of the parts. The results show that the capillary force was enhanced from 8.35 kPa for pure powder to 16.27 kPa for mixed powder by mixing fine powder. The compression strength of green body was enhanced from 1.5 MPa to 3.21 MPa. After sintering, the sample with mixed powder sintered at 1420 °C for 2 h had achieved a maximum density of 95.2%, microhardness of 316 HV, and yield stress of 589 MPa. The relative density of 95.2% of Ti6Al4V parts fabricated by BJ3DP technology in our study is significantly higher than the value reported in the existing literature. Finally, the porous structure with a size of 550 μm was fabricated. Results presented demonstrate that BJ3DP can produce Ti6Al4V parts with excellent properties.

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Investigation of a Short Carbon Fibre-Reinforced Polyamide and Comparison of Two Manufacturing Processes: Fused Deposition Modelling (FDM) and Polymer Injection Moulding (PIM)

Materials ◽

10.3390/ma13030672 ◽

2020 ◽

Vol 13 (3) ◽

pp. 672 ◽

Cited By ~ 7

Author(s):

Elena Verdejo de Toro ◽

Juana Coello Sobrino ◽

Alberto Martínez Martínez ◽

Valentín Miguel Eguía ◽

Jorge Ayllón Pérez

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

3D Printing ◽

Injection Moulding ◽

New Technologies ◽

Mechanical Response ◽

Fused Deposition Modelling ◽

Layer By Layer ◽

Polymer Injection ◽

Fused Deposition

New technologies are offering progressively more effective alternatives to traditional ones. Additive Manufacturing (AM) is gaining importance in fields related to design, manufacturing, engineering and medicine, especially in applications which require complex geometries. Fused Deposition Modelling (FDM) is framed within AM as a technology in which, due to their layer-by-layer deposition, thermoplastic polymers are used for manufacturing parts with a high degree of accuracy and minimum material waste during the process. The traditional technology corresponding to FDM is Polymer Injection Moulding, in which polymeric pellets are injected by pressure into a mould using the required geometry. The increasing use of PA6 in Additive Manufacturing makes it necessary to study the possibility of replacing certain parts manufactured by injection moulding with those created using FDM. In this work, PA6 was selected due to its higher mechanical properties in comparison with PA12. Moreover, its higher melting point has been a limitation for 3D printing technology, and a further study of composites made of PA6 using 3D printing processes is needed. Nevertheless, analysis of the mechanical response of standardised samples and the influence of the manufacturing process on the polyamide’s mechanical properties needs to be carried out. In this work, a comparative study between the two processes was conducted, and conclusions were drawn from an engineering perspective.

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Experimental Investigation on Mechanical Properties of Part Fabricated by Wire Arc Additive Manufacturing Process

Journal of Engineering Research ◽

10.36909/jer.icmmm.15809 ◽

2021 ◽

Author(s):

Vivek Kumar P ◽

◽

Soundrapandian E ◽

Jenin Joseph A ◽

Kanagarajan E ◽

...

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Manufacturing Process ◽

Three Dimensional ◽

Casting Process ◽

Significant Rise ◽

Layer By Layer ◽

Cnc Machine ◽

Hardness Tester ◽

Wire Arc Additive Manufacturing

Additive manufacturing process is a method of layer by layer joining of materials to create components from three-dimensional (3D) model data. After their introduction in the automotive sector a decade ago, it has seen a significant rise in research and growth. The Additive manufacturing is classified into different types based upon the energy source use in the fabrication process. In our project, we used self-build CNC machine that runs MACH3 software, as well as the MACH3 controller is used to control the welding torch motion for material addition through three axis movement (X, Y and Z). In the project we used ER70 S-6 weld wire for the fabrication and examined its microstructure and mechanical properties. Different layers of the specimen had different microstructures, according to microstructural studies of the product. Rockwell hardness tester used for testing hardness of the product. According to the observation of the part fabricated components using the Wire Arc Additive Manufacturing process outperformed the mechanical properties of mild steel casting process. The product fabricated by Wire Arc Additive Manufacturing process properties is superior to conventional casting process.

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