Generalized models for unidirectional anisotropic properties of 3D printed polymers

2020 ◽  
Vol 26 (8) ◽  
pp. 1453-1462
Author(s):  
Jared W. Nelson ◽  
Dylan Atkins ◽  
Matthew L. Gottstine ◽  
Jack Yang ◽  
Gordana Garapic ◽  
...  
Keyword(s):  
Yield Strength ◽  
Exponential Decay ◽  
Design Methodology ◽  
Tensile Tests ◽  
Content Type ◽  
Fused Deposition ◽  
Loading Direction ◽  
3D Printed ◽  
Minimum Yield

Purpose The purpose of this paper is to empirically determine general models and methods for yield strength and modulus at different print orientations adequate for design purposes associated with typical fused deposition modeled (FDM) components/parts. Emphasis was placed on characterizing the impacts of anisotropy and resulting trends independent of material toward developing a method that matched the level of engineering required for current limited structural capabilities of FDM. Design/methodology/approach Tensile tests were performed with a range of unidirectional filament orientations of three different materials allowing for determination of the generalized models, which are then compared to previous findings of others. Findings Though anisotropic trends were similar to previous findings, minimum yield strength was found to be associated with filaments 75° from the loading direction resulting in a sinusoidal generalization. Modulus was found to be best approximated with an exponential decay. Resulting models allow for determination of yield strength and modulus in any orientation of FDM-printed material based on minimal testing. Originality/value This study is the widest range of angles and materials to be tested and analyzed for unidirectional FDM allowing for new trends to be identified. In line with the level of engineering required for most FDM components/parts, the resulting generalized models allow for determination of yield strength and modulus with less computation and minimal testing.

Optimal assembling of 3D printed features by modulation of interfacial behaviour

2019 ◽  
Vol 25 (1) ◽  
pp. 13-21
Author(s):  
Justin Favero ◽  
Sofiane Belhabib ◽  
Sofiane Guessasma ◽  
Hedi Nouri
Keyword(s):  
Design Methodology ◽  
Acrylonitrile Butadiene Styrene ◽  
Interfacial Phenomena ◽  
Fused Deposition Modelling ◽  
Content Type ◽  
Fused Deposition ◽  
Interfacial Behaviour ◽  
3D Printed ◽  
Practical Implications ◽  
Butadiene Styrene

Purpose Assembling items to achieve bigger parts seems to be the solution to counterbalance the dimension limits of 3D printing. This work aims to propose an approach to achieve optimal assembling. Design/methodology/approach Acrylonitrile butadiene styrene polymer samples were printed using fused deposition modelling (FDM). These samples were assembled and the precise contribution of interfacial shearing and tension was measured using simple tensile experiments. Findings The results achieved show the correlation between the printing orientation and the assembling angle. It could be proved that rupture by an interfacial decohesion mechanism of glued parts can be avoided by simple adaptation of the assembling junction. Practical implications Design of large parts using FDM is no more a limitation if assembling configurations are adapted based on the knowledge gained about the interfacial phenomena occurring at the junction position. Originality/value The unbalanced contribution of shearing and tension at the interface defines new assembling profiles that exclude flat junctions.

Analysis of the influence of polylactic acid (PLA) colour on FDM 3D printing temperature and part finishing

2018 ◽  
Vol 24 (8) ◽  
pp. 1305-1316 ◽  
Author(s):  
Juliana Breda Soares ◽  
João Finamor ◽  
Fabio Pinto Silva ◽  
Liane Roldo ◽  
Luis Henrique Cândido
Keyword(s):  
Polylactic Acid ◽  
Three Dimensional ◽  
Mechanical Analysis ◽  
Fused Deposition Modelling ◽  
Process Conditions ◽  
Content Type ◽  
3D Print ◽  
Fused Deposition ◽  
3D Printed

Purpose This paper aims to analyse the effect of different polylactic acid (PLA) colours used on fused deposition modelling (FDM), considering the product finishing quality produced with the same process conditions. Design/methodology/approach The methodology adopted was to design a virtual modelling object and three-dimensional (3D) print it with FDM with different PLA colours (natural, green and black), using the same parameters. 3D scanning and scanning electron microscopy was used to analyse the model finishing of each sample. Fourier-transform infrared spectroscopy analysis, thermogravimetric analysis and dynamic mechanical analysis were used to characterize the material and verify if the colour affected its thermal behaviour. Findings Findings showed that different PLA colours lead to distinct 3D printed finishings under the same process conditions. Thermal analysis showed a reason for the printing finishing difference. The degradation temperatures and the glass temperatures vary depending on the PLA colour. This affects the FDM working temperature. Originality/value This study will contribute to improving the finishing quality of 3D printed products by collaborating to the determination of its process conditions.

Additive manufacturing infill optimization for automotive 3D-printed ABS components

2020 ◽  
Vol 26 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Matt Schmitt ◽  
Raj Mattias Mehta ◽  
Il Yong Kim
Keyword(s):  
High Stress ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Published Data ◽  
Failure Strength ◽  
Content Type ◽  
Fused Deposition ◽  
3D Printed ◽  
Bend Tests ◽  
Point Bend

Purpose Lightweighting of components in the automotive industry is a prevailing trend influenced by both consumer demand and government regulations. As the viability of additively manufactured designs continues to increase, traditionally manufactured components are continually being replaced with 3D-printed parts. The purpose of this paper is to present experimental results and design considerations for 3D-printed acrylonitrile butadiene styrene (ABS) components with non-solid infill sections, addressing a large gap in the literature. Information published in this paper will guide engineers when designing fused deposition modeling (FDM) ABS parts with infill regions. Design/methodology/approach Uniaxial tensile tests and three-point bend tests were performed on 12 different build configurations of 20 samples. FDM with ABS was used as the manufacturing method for the samples. Failure strength and elastic modulus were normalized on print time and specimen mass to quantify variance between configurations. Optimal infill configurations were selected and used in two automotive case study examples. Findings Results obtained from the uniaxial tensile tests and three-point bend tests distinctly showed that component strength is highly influenced by the infill choice selected. Normalized results indicate that solid, double dense and triangular infill, all with eight contour layers, are optimal configurations for component regions experiencing high stress, moderate stress and low stress, respectively. Implementation of the optimal infill configurations in automotive examples yielded equivalent failure strength without normalization and significantly improved failure strength on a print time and mass normalized index. Originality/value To the best of the authors’ knowledge, this is the first paper to experimentally determine and quantify optimal infill configurations for FDM ABS printed parts. Published data in this paper are also of value to engineers requiring quantitative material properties for common infill configurations.

scholarly journals 3D Printed Clamps for In Vitro Tensile Tests of Human Gracilis and the Superficial Third of Quadriceps Tendons

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Biomechanical Properties ◽  
Testing Procedure ◽  
Laboratory Equipment ◽  
Fused Deposition ◽  
Custom Made ◽  
3D Printed

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.

Locating complex eigenvalues for analytical eddy-current models used to detect flaws

2019 ◽  
Vol 38 (6) ◽  
pp. 1800-1809
Author(s):  
Grzegorz Tytko ◽  
Łukasz Dawidowski
Keyword(s):  
Eddy Current ◽  
Design Methodology ◽  
Complex Function ◽  
Precise Determination ◽  
Argument Principle ◽  
Content Type ◽  
Conductive Material ◽  
Complex Roots ◽  
Complex Eigenvalues

Purpose Discrete eigenvalues occur in eddy current problems in which the solution domain was truncated on its edge. In case of conductive material with a hole, the eigenvalues are complex numbers. Their computation consists of finding complex roots of a complex function that satisfies the electromagnetic interface conditions. The purpose of this paper is to present a method of computing complex eigenvalues that are roots of such a function. Design/methodology/approach The proposed approach involves precise determination of regions in which the roots are found and applying sets of initial points, as well as the Cauchy argument principle to calculate them. Findings The elaborated algorithm was implemented in Matlab and the obtained results were verified using Newton’s method and the fsolve procedure. Both in the case of magnetic and nonmagnetic materials, such a solution was the only one that did not skip any of the eigenvalues, obtaining the results in the shortest time. Originality/value The paper presents a new effective method of locating complex eigenvalues for analytical solutions of eddy current problems containing a conductive material with a hole.

Deposition-induced effects of isotactic polypropylene and polycarbonate composites during fused deposition modeling

2017 ◽  
Vol 23 (5) ◽  
pp. 869-880 ◽  
Author(s):  
Ying-Guo Zhou ◽  
Bei Su ◽  
Lih-sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Fused Deposition Modeling ◽  
Content Type ◽  
Fused Deposition ◽  
Close Relationship ◽  
Molded Parts ◽  
Deposition Modeling ◽  
Injection Molded ◽  
First Time

Purpose Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites. Design/methodology/approach For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces. Findings The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing. Originality/value This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

Shear band propagation in honeycombs: numerical and experimental

2018 ◽  
Vol 24 (2) ◽  
pp. 477-484
Author(s):  
Hossein Goodarzi Hosseinabadi ◽  
Reza Bagheri ◽  
Volker Altstädt
Keyword(s):  
Finite Element ◽  
Shear Band ◽  
Energy Absorption ◽  
Image Correlation ◽  
Correlation Technique ◽  
Deformation Localization ◽  
Content Type ◽  
Fused Deposition ◽  
Absorption Potential ◽  
3D Printed

Purpose Hexagonal honeycombs with meso-metric cell size show excellent load bearing and energy absorption potential, which make them attractive in many applications. However, owing to their bend-dominated structure, honeycombs are susceptible to deformation localization. The purpose of this study is to provide insight about shear band propagation in struts of 3D-printed honeycombs and its relation to the achieved macroscopic mechanical behavior. Design/methodology/approach Hexagonal honeycombs and unit cell models are 3D-printed by fused deposition modeling (FDM). The samples are exposed to compression loading and digital image correlation technique and finite element analyses are incorporated. Findings It is found that the strain contours, which are obtained by finite element, are in agreement with experimental measurements made by DIC. In addition, three stages of shear band propagation in struts of 3D-printed honeycombs are illustrated. Then the correlation between shear band propagation stages and the achieved macroscopic mechanical responses is discussed in detail. Originality/value For the first time, a hierarchical activation of different modes of shear band propagation in struts of a 3D-printed honeycomb is reported. This information can be of use for designing a new generation of honeycombs with tailor-made localization and energy absorption potential.

Experimental investigations into abrasive flow machining (AFM) of 3D printed ABS and PLA parts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nitin Dixit ◽  
Varun Sharma ◽  
Pradeep Kumar
Keyword(s):  
Surface Roughness ◽  
Biomedical Applications ◽  
Fused Deposition Modeling ◽  
Experimental Investigations ◽  
Future Research ◽  
Content Type ◽  
Abrasive Flow Machining ◽  
Fused Deposition ◽  
Cylindrical Parts ◽  
3D Printed

Purpose The surface roughness of additively manufactured parts is usually found to be high. This limits their use in industrial and biomedical applications. Therefore, these parts required post-processing to improve their surface quality. The purpose of this study is to finish three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) parts using abrasive flow machining (AFM). Design/methodology/approach A hydrogel-based abrasive media has been developed to finish 3D printed parts. The developed abrasive media has been characterized for its rheology and thermal stability using sweep tests, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The ABS and PLA cylindrical parts have been prepared using fused deposition modeling (FDM) and finished using AFM. The experiments were designed using Taguchi (L9 OA) method. The effect of process parameters such as extrusion pressure (EP), layer thickness (LT) and abrasive concentration (AC) was investigated on the amount of material removed (MR) and percentage improvement in surface roughness (%ΔRa). Findings The developed abrasive media was found to be effective for finishing FDM printed parts using AFM. The microscope images of unfinished and finished showed a significant improvement in surface topography of additively manufactures parts after AFM. The results reveal that AC is the most significant parameter during the finishing of ABS parts. However, EP and AC are the most significant parameters for MR and %ΔRa, respectively, during the finishing of PLA parts. Practical implications The FDM technology has applications in the biomedical, electronics, aeronautics and defense sectors. PLA has good biodegradable and biocompatible properties, so widely used in biomedical applications. The ventilator splitters fabricated using FDM have a profile similar to the shape used in the present study. Research limitations/implications The present study is focused on finishing FDM printed cylindrical parts using AFM. Future research may be done on the AFM of complex shapes and freeform surfaces printed using different additive manufacturing (AM) techniques. Originality/value An abrasive media consists of xanthan gum, locust bean gum and fumed silica has been developed and characterized. An experimental study has been performed by combining printing parameters of FDM and finishing parameters of AFM. A comparative analysis in MR and %ΔRa has been reported between 3D printed ABS and PLA parts.

Use of polymer concrete for large-scale 3D printing

2021 ◽  
Vol 27 (3) ◽  
pp. 465-474
Author(s):  
Martin Krčma ◽  
David Škaroupka ◽  
Petr Vosynek ◽  
Tomáš Zikmund ◽  
Jozef Kaiser ◽  
...  
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Mechanical Performance ◽  
Construction Material ◽  
Polymer Concrete ◽  
Fused Deposition Modelling ◽  
Cast State ◽  
Content Type ◽  
Fused Deposition ◽  
3D Printed

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropylene and glass sand, is printed by the fused deposition modelling process. The process of material and parameter selection is described. The mechanical properties of the filled material were compared to its cast state. Samples were made from castings and two different orientations of 3D-printed parts. Three-point flex tests were carried out, and the area of the break was examined. Computed tomography of the samples was carried out. Findings The influence of the 3D printing process on the material was evaluated. The mechanical performance of the longitudinal samples was close to the cast state. There was a difference in the failure mode between the states, with cast parts exhibiting a tougher behaviour, with fractures propagating in a stair-like manner. The 3D-printed samples exhibited high degrees of porosity. Originality/value The results suggest that the novel material is a good fit for 3D printing, with little to no degradation caused by the process. Layer adhesion was shown to be excellent, with negligible effect on the finished part for the longitudinal orientation. That means, if large-scale testing of buildability is successful, the material is a good fit for additive manufacturing of building components and other large-scale structures.

Causality in qualitative market and social research

2019 ◽  
Vol 22 (3) ◽  
pp. 405-413
Author(s):  
Clive Roland Boddy
Keyword(s):  
Qualitative Research ◽  
Design Methodology ◽  
Social Research ◽  
Pragmatic Approach ◽  
Social Phenomena ◽  
Content Type ◽  
The Past ◽  
The Moment ◽  
Practical Implications

Purpose Academic qualitative researchers have been criticized for rejecting the idea that their research can establish causality while market and social researchers, with their realist and pragmatic approach to research, take for granted that it can. This paper aims to explore the ability of qualitative research to determine cause and effect in terms of market and social phenomena. Design/methodology/approach The literature on causality in qualitative research is reviewed and discussed. The discussion is further informed by the author’s own experience of undertaking commercial and academic market and social qualitative research over the past 33 years. Findings In qualitative market and social research, the determination of causality is often needed but rarely discussed. This paper explores this occurrence and brings to the fore, via discussion and the use of example, the ways in which causality can be determined by qualitative research. Practical implications A determination of what events bring about predictable changes in social and market environments can be established via qualitative research particularly at a probabilistic level of causality. This implies that policymakers should give a greater emphasis to qualitative findings than then sometimes do at the moment. Originality/value Causality in market and social research is rarely discussed by practitioners but is nevertheless a premise of much of the qualitative research that is undertaken. This paper is therefore distinctive in that it examines whether this premise is justifiable.

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