Properties and role of interfaces in multimaterial 3D printed composites

AbstractIn polyjet printing photopolymer droplets are deposited on a build tray, leveled off by a roller and cured by UV light. This technique is attractive to fabricate heterogeneous architectures combining compliant and stiff constituents. Considering the layer-by-layer nature, interfaces between different photopolymers can be formed either before or after UV curing. We analyzed the properties of interfaces in 3D printed composites combining experiments with computer simulations. To investigate photopolymer blending, we characterized the mechanical properties of the so-called digital materials, obtained by mixing compliant and stiff voxels according to different volume fractions. We then used nanoindentation to measure the spatial variation in mechanical properties across bimaterial interfaces at the micrometer level. Finally, to characterize the impact of finite-size interfaces, we fabricated and tested composites having compliant and stiff layers alternating along different directions. We found that interfaces formed by deposition after curing were sharp whereas those formed before curing showed blending of the two materials over a length scale bigger than individual droplet size. We found structural and functional differences of the layered composites depending on the printing orientation and corresponding interface characteristics, which influenced deformation mechanisms. With the wide dissemination of 3D printing techniques, our results should be considered in the development of architectured materials with tailored interfaces between building blocks.

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Parameters Affecting the Mechanical Properties of Three-Dimensional (3D) Printed Carbon Fiber-Reinforced Polylactide Composites

Polymers ◽

10.3390/polym12112456 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2456

Author(s):

Demei Lee ◽

Guan-Yu Wu

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

3D Printing ◽

Three Dimensional ◽

Fused Deposition Modelling ◽

Layer By Layer ◽

Fused Deposition ◽

Bed Temperature ◽

3D Printed ◽

The Impact

Three-dimensional (3D) printing is a manufacturing technology which creates three-dimensional objects layer-by-layer or drop-by-drop with minimal material waste. Despite the fact that 3D printing is a versatile and adaptable process and has advantages in establishing complex and net-shaped structures over conventional manufacturing methods, the challenge remains in identifying the optimal parameters for the 3D printing process. This study investigated the influence of processing parameters on the mechanical properties of Fused Deposition Modelling (FDM)-printed carbon fiber-filled polylactide (CFR-PLA) composites by employing an orthogonal array model. After printing, the tensile and impact strengths of the printed composites were measured, and the effects of different parameters on these strengths were examined. The experimental results indicate that 3D-printed CFR-PLA showed a rougher surface morphology than virgin PLA. For the variables selected in this analysis, bed temperature was identified as the most influential parameter on the tensile strength of CFR-PLA-printed parts, while bed temperature and print orientation were the key parameters affecting the impact strengths of printed composites. The 45° orientation printed parts also showed superior mechanical strengths than the 90° printed parts.

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The Impact of Slicing Softwares on the Mechanical Properties of 3D Printed Parts

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b3668.079220 ◽

2020 ◽

Vol 9 (2) ◽

pp. 487-494

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Tensile Strength ◽

Ultimate Tensile Strength ◽

3D Printer ◽

Stl File ◽

3D Printed ◽

Intersection Curves ◽

The Impact

“Slicing tool” or “Slicing Software” computes the intersection curves of models and slicing planes. They improve the quality of the model being printed when given in the form of STL file. Upon analyzing a specimen that has been printed using two different slicing tools, there was a drastic variation on account of the mechanical properties of the specimen. The ultimate tensile strength and the surface roughness of the material vary from one tool to another. This paper reports an investigation and analysis of the variation in the ultimate tensile strength and the surface roughness of the specimen, given that the 3D printer and the model being printed is the same, with a variation of usage of slicing software. This analysis includes ReplicatorG, Flashprint as the two different slicing tools that are used for slicing of the model. The variation in the ultimate tensile strength and the surface roughness are measured and represented statistically through graphs. An appropriate decisive conclusion was drawn on the basis of the observations and analysis of the experiment on relevance to the behavior and mechanical properties of the specimen.

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Comparison of Dental Stone Models and Their 3D Printed Acrylic Replicas for the Accuracy and Mechanical Properties

Materials ◽

10.3390/ma13184066 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4066

Author(s):

Marta Czajkowska ◽

Ewa Walejewska ◽

Łukasz Zadrożny ◽

Monika Wieczorek ◽

Wojciech Święszkowski ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Impact Strength ◽

Physical Properties ◽

Diagnostic Tool ◽

Medical Records ◽

Diagnostic Value ◽

Dental Models ◽

3D Printed ◽

The Impact

This study was conducted to test possibilities of application of 3D printed dental models (DMs) in terms of their accuracy and physical properties. In this work, stone models of mandibles were cast from alginate impressions of 10 patients and scanned in order to obtain 3D printed acrylic replicas. The diagnostic value was tested as matching of model scans on three levels: peak of cusps, occlusal surface, and all teeth surfaces. The mechanical properties of acrylic and stone samples, specifically the impact strength, shore D hardness, and flexural and compressive strength were investigated according to ISO standards. The matching of models’ surfaces was the highest on the level of peaks of cusps (average lack of deviations, 0.21 mm) and the lowest on the level of all teeth surfaces (average lack of deviations, 0.64 mm). Acrylic samples subjected to mechanical testing, as expected, showed higher mechanical properties as compared to the specimens made of dental stone. In the present study we demonstrated that 3D printed acrylic models could be ideal representatives in the case of use as a diagnostic tool and as a part of medical records. The acrylic samples exhibited not only higher mechanical properties, but also showed better accuracy comparing to dental stone.

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EFFECT RESEARCH OF SURFACE DEFORMATION IMPACT AND THERMAL TREATMENT AT MULTI-LAYER WELD DEPOSITION UPON MECHANICAL PROPERTIES AND POROSITY OF ALUMINUM ALLOY 1580

Bulletin of Bryansk state technical university ◽

10.30987/1999-8775-2020-6-22-30 ◽

2020 ◽

Vol 2020 (6) ◽

pp. 22-30

Author(s):

Maksim Kartashev ◽

Dmitriy Panov ◽

Maksim Mindibaev ◽

Gleb Permyakov ◽

Dmitriy Trushnikov

Keyword(s):

Mechanical Properties ◽

Aluminum Alloy ◽

Thermal Treatment ◽

Surface Deformation ◽

Mode Selection ◽

High Strength ◽

Layer By Layer ◽

Deformation Effect ◽

The Impact ◽

Layer Deformation

The experimental research of mechanical properties and porosity of samples made of experimental high-strength magnesium-scandium aluminum alloy 1580 obtained through the method of multi-layer weld deposition including the application of deformation strengthening and also the further thermal treatment is carried out. There is investigated the impact of layer-by-layer deformation strengthening with the further thermal treatment upon mechanical properties and porosity of the samples of experimental high-strength aluminum alloy 1580 having magnesium-scandium during multi-layer weld deposition. There are shown the values of mechanical properties and porosity of samples subject to modes of deformation strengthening and thermal treatment. A possibility of the impact of deformation effect and thermal treatment upon porosity and mechanical properties of products made of aluminum alloys containing magnesium-scandium obtained during multi-layer SMT weld deposition is checked up. According to the results of the investigation there are drawn conclusions: it is determined that for porosity decrease in metal deposited there are required higher values of efforts of the deformation impact and a weld deposition mode selection excluding product over-heating influencing porosity of metal deposited; thermal treatment impact upon porosity of the metal deposited is not defined; the samples obtained with the use of deformation impact and long annealing with the duration more than six hours have higher mechanical properties.

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Influence of nozzle temperature and volumetric filling on the mechanical properties of 3D-printed PEEK

Materials Testing ◽

10.1515/mt-2020-620404 ◽

2020 ◽

Vol 62 (4) ◽

pp. 351-356

Author(s):

Danny Vogel ◽

Volker Weißmann ◽

Leo Rührmund ◽

Harald Hansmann ◽

Rainer Bader

Keyword(s):

Mechanical Properties ◽

Fused Deposition Modeling ◽

Bending Strength ◽

Layer By Layer ◽

Bending Properties ◽

Filling Degree ◽

Fused Deposition ◽

3D Printed ◽

Injection Molded ◽

Nozzle Temperature

Abstract Fused deposition modeling is a layer-by-layer 3D printing technology used to additively manufacture polymers. A major benefit of 3D-printed polymers is the option of tailoring their mechanical properties by varying the process parameters. In addition, the present study investigates the influence of the filling degree (50 % or 100 %) and the nozzle temperature during manufacturing on the mechanical properties of 3D-printed poly-ether-ether-ketone (PEEK) material. PEEK samples were built either compact (filling degree 100 %) or closed-cell porous (filling degree 50 %), using three different nozzle temperatures (390 °C, 430 °C and 470 °C). In static bending tests, the bending properties were evaluated and compared with injection molded PEEK samples. Bending strength and modulus increased up to 21.1 %, when the nozzle temperature was increased and up to 40.8 % when the volumetric filling was altered. The results indicate that nozzle temperature and volumetric filling can be altered to tailor the bending properties of 3D-printed PEEK for particular applications. However, the mechanical properties of the 3D-printed samples determined in the current study could not achieve those of the properties of the injection molded PEEK.

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Cationic UV-Curing of Epoxidized Biobased Resins

Polymers ◽

10.3390/polym13010089 ◽

2020 ◽

Vol 13 (1) ◽

pp. 89

Author(s):

Camilla Noè ◽

Minna Hakkarainen ◽

Marco Sangermano

Keyword(s):

Mechanical Properties ◽

Organic Compound ◽

Epoxy Resins ◽

Chemical Resistance ◽

State Of The Art ◽

Uv Curing ◽

Building Blocks ◽

Uv Curable ◽

Curing Conditions ◽

Volatile Organic

Epoxy resins are among the most important building blocks for fabrication of thermosets for many different applications thanks to their superior thermo-mechanical properties and chemical resistance. The recent concerns on the environmental problems and the progressive depletion of petroleum feedstocks have drawn the research interest in finding biobased alternatives. Many curing techniques can be used to obtain the final crosslinked thermoset networks. The UV-curing technology can be considered the most environmentally friendly because of the absence of volatile organic compound (VOC) emissions and mild curing conditions. This review provides an overview of the state of the art of bio-based cationic UV-curable epoxy resins. Particular focus has been given to the sources of the bio-based epoxy monomers and the applications of the obtained products.

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The Impact of Defects on Tensile Strength and Modulus of 3D Printed Parts Manufactured by Fused deposition Modeling

10.32920/ryerson.14653614.v1 ◽

2021 ◽

Author(s):

Mobina Movahedi

Keyword(s):

Tensile Strength ◽

3D Printing ◽

Fused Deposition Modeling ◽

Research Work ◽

Layer By Layer ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed ◽

The Impact ◽

Printing Direction

Additive manufacturing (AM), 3D printing, is defined as a process of depositing materials layer by layer to create three-dimensional printed models, as opposed to subtractive manufacturing methodologies. It has the potential of revolutionizing field of manufacturing, which allows us to create more complex geometries with lower cost and faster speed in comparison to injection molding, compression forming, and forging. Therefore, 3D printing can shorten the design manufacturing cycle, reduce the production cost, and increase the competitiveness. Due to the improvements of processes and advancements of modeling and design, Fused Deposition Modeling (FDM) technologies, a common 3D printing technique, have been involved in wide various applications in the past three decades and numerous studies have been gathered. This research work studies directional properties of FDM 3D printed thermoplastic parts per ASTM D638. Tensile strength and modulus of the coupons along and perpendicular to the printing direction are evaluated. It is observed that FDM 3D printing introduces anisotropic behavior to the manufactured part, e.g. tensile strength of 57.7 and 30.8 MPa for loading along and perpendicular to the printing direction, respectively. FDM 3D printers are not ideal and introduce defects into the manufactured parts, e.g. in the form of missing material, gap. This study investigates the impact of gaps on tensile strength and modulus of 3D printed parts. A maximum reduction of 20% in strength is found for a gap (missing bead) along the loading direction.

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The Impact of Defects on Tensile Strength and Modulus of 3D Printed Parts Manufactured by Fused deposition Modeling

10.32920/ryerson.14653614 ◽

2021 ◽

Author(s):

Mobina Movahedi

Keyword(s):

Tensile Strength ◽

3D Printing ◽

Fused Deposition Modeling ◽

Research Work ◽

Layer By Layer ◽

Fused Deposition ◽

Deposition Modeling ◽

3D Printed ◽

The Impact ◽

Printing Direction

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Advances in cationic photopolymerization

Pure and Applied Chemistry ◽

10.1351/pac-con-12-04-11 ◽

2012 ◽

Vol 84 (10) ◽

pp. 2089-2101 ◽

Cited By ~ 52

Author(s):

Marco Sangermano

Keyword(s):

Mechanical Properties ◽

Uv Light ◽

Uv Curing ◽

Vinyl Ethers ◽

Good Adhesion ◽

High Interest ◽

Onium Salts ◽

Cationic Photopolymerization

This review discusses cationic UV-curing processes of vinyl ethers, propenyl ethers, and epoxy monomers. Cationic photopolymerization based on photogeneration of acid from onium salts induced by UV light and consecutive polymerization initiated by photogenerated acid was first proposed at the end of the 1970s. The process engendered high interest both in academia and in industry. Cationic photoinduction presents some advantages over comparable radical-mediated processes, particularly the absence of inhibition by oxygen, low shrinkage, and good adhesion, and mechanical properties of the UV-cured materials. Moreover, the monomers employed are generally less toxic and irritant than acrylates and methacrylates, which are widely used in radical photopolymerization. In this overview, particular emphasis is given to our recent contributions to the field of cationic photopolymerization for different classes of monomers.

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The Effect of Binder Loading on the Pore Size of 3D Printed PMMA

Materials ◽

10.3390/ma14051190 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1190

Author(s):

Simon Riechmann ◽

Odo Wunnicke ◽

Arno Kwade

Keyword(s):

Mechanical Properties ◽

Pore Size ◽

Capillary Flow ◽

Tensile Tests ◽

Layer By Layer ◽

Powder Bed ◽

Close Relationship ◽

3D Printed ◽

Binder Jetting ◽

Pmma Powder

Binder jetting is known to produce porous objects by depositing the binder selectively layer by layer on a powder bed. In this study, the pore size of printed parts and the correlating mechanical properties are investigated on a commercially available PMMA powder binder system. Pore sizes are measured via capillary flow porometry and mechanical properties via tensile tests. Porometry indicates that the pore size stays at a constant level of 22 µm at 5 to 10 wt% binder loading before decreasing to 6 µm at loadings of 30 wt% or higher. The results were compared with the mechanical testing and related to the agglomerate strength model of Rumpf. The highlights of the article are the application of a binder jetted part as a filter and the identification of a close relationship between porosity and mechanical strength, similar to phenomena in agglomeration science.

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