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Article
Publication date: 2 February 2021

Ali Alperen Bakır, Resul Atik and Sezer Özerinç

This paper aims to provide an overview of the recent findings of the mechanical properties of parts manufactured by fused deposition modeling (FDM). FDM has become a…

Abstract

Purpose

This paper aims to provide an overview of the recent findings of the mechanical properties of parts manufactured by fused deposition modeling (FDM). FDM has become a widely used technique for the manufacturing of thermoplastic parts. The mechanical performance of these parts under service conditions is difficult to predict due to the large number of process parameters involved. The review summarizes the current knowledge about the process-property relationships for FDM-based three-dimensional printing.

Design/methodology/approach

The review first discusses the effect of material selection, including pure thermoplastics and polymer-matrix composites. Second, process parameters such as nozzle temperature, raster orientation and infill ratio are discussed. Mechanisms that these parameters affect the specimen morphology are explained, and the effect of each parameter on the strength of printed parts are systematically presented.

Findings

Mechanical properties of FDM-produced parts strongly depend on process parameters and are usually lower than injection-molded counterparts. There is a need to understand the effect of each parameter and any synergistic effects involved better.

Practical implications

Through the optimization of process parameters, FDM has the potential to produce parts with strength values matching those produced by conventional methods. Further work in the field will make the FDM process more suitable for the manufacturing of load-bearing components.

Originality/value

This paper presents a critical assessment of the current knowledge about the mechanical properties of FDM-produced parts and suggests future research directions.

Details

Rapid Prototyping Journal, vol. 27 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 24 August 2021

Sunthorn Chaitat, Nattapon Chantarapanich and Sujin Wanchat

This paper aims to investigate effect of infill density, fabricated built orientation and dose of gamma radiation to mechanical tensile and compressive properties of…

Abstract

Purpose

This paper aims to investigate effect of infill density, fabricated built orientation and dose of gamma radiation to mechanical tensile and compressive properties of polylactic acid (PLA) part fabricated by fused deposit modelling (FDM) technique for medical applications.

Design/methodology/approach

PLA specimens for tensile and compressive tests were fabricated using FDM machine. The specimens geometry and test method were referred to ASTM D638 and ASTM D695, respectively. Three orientations under consideration were flat, edge and upright, whereas the infill density ranged from 0 to 100%. The gamma radiation dose used to expose to specimens was 25 kGy. The collected data included stress and strain, which was used to find mechanical properties, i.e. yield strength, ultimate tensile strength (UTS), fracture strength, elongation at yield, elongation at UTS and elongation at break. The t-test was used to access the difference in mechanical properties.

Findings

Compressive mechanical properties is greater than tensile mechanical properties. Increasing number of layer parallel to loading direction and infill density, it enhances the material property. Upright presents the lowest mechanical property in tensile test, but greatest in compressive test. Upright orientation should not be used for part subjecting to tensile load. FDM is more proper for part subjecting to compressive load. FDM part requires undergoing gamma ray for sterilisation, the infill density no less than 70 and 60% should be selected for part subjecting to tensile and compressive load, respectively.

Originality/value

This study investigated all mechanical properties in both tension and compression as well as exposure to gamma radiation. The results can be applied in selection of FDM parameters for medical device manufacturing.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 6 July 2020

Johanna J. Schwartz, Joshua Hamel, Thomas Ekstrom, Leticia Ndagang and Andrew J. Boydston

Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of…

Abstract

Purpose

Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications. Successfully manufacturing objects using ME three-dimensional printers can often require numerous iterations to attain predictable performance because the exact mechanical behavior of parts fabricated via additive processes are difficult to predict. One of that factors that contributes to this difficulty is the wide variety of ME feed stock materials currently available in the marketplace. These build materials are often sold based on their base polymer material such as acrylonitrile butadiene styrene or polylactic acid (PLA), but are produced by numerous different commercial suppliers in a wide variety of colors using typically undisclosed additive feed stocks and base polymer formulations. This paper aims to present the results from an experimental study concerned with quantifying how these sources of polymer variability can affect the mechanical behavior of three-dimensional printed objects. Specifically, the set of experiments conducted in this study focused on following: several different colors of PLA filament from a single commercial supplier to explore the effect of color additives and three filaments of the same color but produced by three different suppliers to account for potential variations in polymer formulation.

Design/methodology/approach

A set of five common mechanical and material characterization tests were performed on 11 commercially available PLA filaments in an effort to gain insight into the variations in mechanical response that stem from variances in filament manufacturer, feed stock polymer, additives and processing. Three black PLA filaments were purchased from three different commercial suppliers to consider the variations introduced by use of different feed stock polymers and filament processing by different manufacturers. An additional eight PLA filaments in varying colors were purchased from one of the three suppliers to focus on how color additives lead to property variations. Some tests were performed on unprocessed filament samples, while others were performed on objects three-dimensional printed from the various filaments. This study looked specifically at four mechanical properties (Young’s modulus, storage modulus, yield strength and toughness) as a function of numerous material properties (e.g. additive loading, molecular weight, molecular weight dispersity, enthalpy of melting and crystallinity).

Findings

For the 11 filaments tested the following mean values and standard deviations were observed for the material properties considered: pa = 1.3 ± 0.9% (percent additives), Mw = 98.6 ± 16.4 kDa (molecular weight), Ð = 1.33 ± 0.1 (molecular weight dispersity), Hm = 37.4 ± 7.2 J/g (enthalpy of melting) and = 19.6 ± 2.1% (crystallinity). The corresponding mean values and standard deviations for the resulting mechanical behaviors were: E = 2,790 ± 145 MPa (Young’s modulus), E’ = 1,050 ± 125 MPa (storage modulus), Sy = 49.6 ± 4.93 MPa (yield strength) and Ut = 1.87 ± 0.354 MJ/m^3 (toughness). These variations were observed in filaments that were all manufactured from the same base polymer (e.g. PLA) and are only different in terms of the additives used by the manufacturers to produce different colors or different three-dimensional printing performance. Unfortunately, while the observed variations were significant, no definitive strong correlations were found between these observed variations in the mechanical behavior of the filaments studied and the considered material properties.

Research limitations/implications

These variations in mechanical behavior and material properties could not be ascribed to any specific factor, but rather show that the mechanical of three-dimensional printed parts are potentially affected by variations in base polymer properties, additive usage and filament processing choices in complex ways that can be difficult to predict.

Practical implications

These results emphasize the need to take processing and thereby even filament color, into account when using ME printers, they emphasize the need for designers to use AM with caution when the mechanical behavior of a printed part is critical and they highlight the need for continued research in this important area. While all filaments used were marked as PLA, the feedstock materials, additives and processing conditions created significant differences in the mechanical behavior of the printed objects evaluated, but these differences could not be accurately and reliably predicted as function of the observed material properties that were the focus of this study.

Originality/value

The testing methods used in the study can be used by engineers and creators alike to better analyze the material properties of their filament printed objects, to increase success in print and mechanical design. Furthermore, the results clearly show that as AM continues to evolve and grow as a manufacturing method, standardization of feedstock processing conditions and additives would enable more reliable and repeatable printed objects and would better assist designers in effectively implementing AM methods.

Details

Rapid Prototyping Journal, vol. 26 no. 7
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 December 2004

George K. Stylios

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…

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Abstract

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 16 no. 6
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 16 January 2017

Hengky Eng, Saeed Maleksaeedi, Suzhu Yu, Yu Ying Clarrisa Choong, Florencia Edith Wiria, Ruihua Eugene Kheng, Jun Wei, Pei-Chen Su and Huijun Phoebe Tham

Polymeric parts produced by 3D stereolithography (SL) process have poorer mechanical properties as compared to their counterparts fabricated via conventional methods, such…

Abstract

Purpose

Polymeric parts produced by 3D stereolithography (SL) process have poorer mechanical properties as compared to their counterparts fabricated via conventional methods, such as injection or compression molding. Adding nanofillers in the photopolymer resin for SL could help improve mechanical properties. This study aims to achieve enhancement in mechanical properties of parts fabricated by SL, for functional applications, by using well-dispersed nanofillers in the photopolymers, together with suitable post-processing.

Design/methodology/approach

Carbon nanotubes (CNTs) have high strength and Young’s modulus, making them attractive nanofillers. However, dispersion of CNTs in photopolymer is a critical challenge, as they tend to agglomerate easily. Achieving good dispersion is crucial to improve the mechanical properties; thus, suitable dispersion mechanisms and processes are examined. Solvent exchange process was found to improve the dispersion of multiwalled carbon nanotubes in the photopolymer. The UV-absorbing nature of CNTs was also discovered to affect the curing properties. With suitable post processing, coupled with thermal curing, the mechanical properties of SL parts made from CNTs-filled resin improved significantly.

Findings

With the addition of 0.25 wt.% CNTs into the photopolymer, tensile stress and elongation of the 3D printed parts increased by 70 and 46 per cent, respectively. With the significant improvement, the achieved tensile strength is comparable to parts manufactured by conventional methods.

Practical implications

This allows functional parts to be manufactured using SL.

Originality/value

In this paper, an improved procedure to incorporate CNTs into the photopolymer was developed. Furthermore, because of strong UV-absorption nature of CNTs, curing properties of photopolymer and SL parts with and without CNT fillers were studied. Optimized curing parameters were determined and additional post-processing step for thermal curing was discovered as an essential step in order to further enhance the mechanical properties of SL composite parts.

Details

Rapid Prototyping Journal, vol. 23 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 11 September 2019

Swapnil Vyavahare, Soham Teraiya, Deepak Panghal and Shailendra Kumar

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique…

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1565

Abstract

Purpose

Fused deposition modelling (FDM) is the most economical additive manufacturing technique. The purpose of this paper is to describe a detailed review of this technique. Total 211 research papers published during the past 26 years, that is, from the year 1994 to 2019 are critically reviewed. Based on the literature review, research gaps are identified and the scope for future work is discussed.

Design/methodology/approach

Literature review in the domain of FDM is categorized into five sections – (i) process parameter optimization, (ii) environmental factors affecting the quality of printed parts, (iii) post-production finishing techniques to improve quality of parts, (iv) numerical simulation of process and (iv) recent advances in FDM. Summary of major research work in FDM is presented in tabular form.

Findings

Based on literature review, research gaps are identified and scope of future work in FDM along with roadmap is discussed.

Research limitations/implications

In the present paper, literature related to chemical, electric and magnetic properties of FDM parts made up of various filament feedstock materials is not reviewed.

Originality/value

This is a comprehensive literature review in the domain of FDM focused on identifying the direction for future work to enhance the acceptability of FDM printed parts in industries.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 21 March 2016

Jonathan Torres, Matthew Cole, Allen Owji, Zachary DeMastry and Ali P. Gordon

This paper aims to present the influences of several production variables on the mechanical properties of specimens manufactured using fused deposition modeling (FDM) with…

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1685

Abstract

Purpose

This paper aims to present the influences of several production variables on the mechanical properties of specimens manufactured using fused deposition modeling (FDM) with polylactic acid (PLA) as a media and relate the practical and experimental implications of these as related to stiffness, strength, ductility and generalized loading.

Design/methodology/approach

A two-factor-level Taguchi test matrix was defined to allow streamlined mechanical testing of several different fabrication settings using a reduced array of experiments. Specimens were manufactured and tested according to ASTM E8/D638 and E399/D5045 standards for tensile and fracture testing. After initial analysis of mechanical properties derived from mechanical tests, analysis of variance was used to infer optimized production variables for general use and for application/load-specific instances.

Findings

Production variables are determined to yield optimized mechanical properties under tensile and fracture-type loading as related to orientation of loading and fabrication.

Practical implications

The relation of production variables and their interactions and the manner in which they influence mechanical properties provide insight to the feasibility of using FDM for rapid manufacturing of components for experimental, commercial or consumer-level use.

Originality/value

This paper is the first report of research on the characterization of the mechanical properties of PLA coupons manufactured using FDM by the Taguchi method. The investigation is relevant both in commercial and consumer-level aspects, given both the currently increasing utilization of 3D printers for component production and the viability of PLA as a renewable, biocompatible material for use in structural applications.

Details

Rapid Prototyping Journal, vol. 22 no. 2
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 June 2014

Grazielle de Oliveira Setti, Marcelo Fernandes de Oliveira, Izaque Alves Maia, Jorge Vicente Lopes da Silva, Raluca Savu and Ednan Joanni

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by…

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1141

Abstract

Purpose

The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by selective laser sintering (SLS) to assess a possible correlation between them.

Design/methodology/approach

Fabrication of Nylon 12 (Duraform PA®) samples using different laser power levels and their characterization by tensile testing, roughness and Raman scattering measurements.

Findings

Among the surface methods investigated, the results from Raman spectroscopy are the best ones, but methods dependent on surface analysis are not really suitable as indicators of the mechanical properties. The correlation coefficients for linear fitting obtained when the normalized results of mechanical properties are plotted against the surface properties are too low. Furthermore, the ambiguity between surface and mechanical data makes it impossible to use these surface properties for prediction purposes in the industrial environment.

Originality/value

Quantitative evaluation and correlation between mechanical properties and surface properties of SLS-made samples.

Details

Rapid Prototyping Journal, vol. 20 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 20 June 2019

Androniki Tsiamaki and Nicolaos Anifantis

The purpose of this paper is to simulate and investigate the thermomechanical properties of graphene-reinforced nanocomposites.

Abstract

Purpose

The purpose of this paper is to simulate and investigate the thermomechanical properties of graphene-reinforced nanocomposites.

Design/methodology/approach

The analysis proposed consists of two stages. In the first stage, the temperature-dependent mechanical properties of graphene are estimated while in the second stage, using the previously derived properties, the temperature-dependent properties of graphene-reinforced PMMA nanocomposites are investigated. In the first stage of the analysis, graphene is modeled discretely using molecular mechanics theory where the interatomic interactions are simulated by spring elements of temperature-dependent stiffness. The graphene sheets are composed of either one or more (up to five) monolayer graphene sheets connected via van der Waals interactions. However, in the second analysis stage, graphene is modeled equivalently as continuum medium and is positioned between two layers of PMMA. Also, the interphase between two materials is modeled as a medium with mechanical properties defined and bounded by the two materials.

Findings

The mechanical properties including Young’s modulus, shear modulus and Poisson’s ratio due to temperature changes are estimated. The numerical results show that the temperature rise and the multiplicity of graphene layers considered lead to a decrease of the mechanical properties.

Originality/value

The present analysis proposes an easy and accurate method for the estimation of the temperature-dependent mechanical properties of graphene-reinforced nanocomposites.

Details

International Journal of Structural Integrity, vol. 11 no. 5
Type: Research Article
ISSN: 1757-9864

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Article
Publication date: 5 October 2020

Mozhgan Sayanjali, Amir Masood Rezadoust and Foroud Abbassi Sourki

This paper aims to focus on the development of the three-dimensional (3D) printing filaments based on acrylonitrile butadiene styrene (ABS) copolymer and…

Abstract

Purpose

This paper aims to focus on the development of the three-dimensional (3D) printing filaments based on acrylonitrile butadiene styrene (ABS) copolymer and styrene-ethylene/butylene-styrene (SEBS) block copolymer, with tailored viscoelastic properties and controlled flow during the 3D printing process.

Design/methodology/approach

In this investigation, ABS was blended with various amounts of SEBS via a melt mixing process. Then the ABS/SEBS filaments were prepared by a single-screw extruder and printed by the FDM method. The rheological properties were determined using an MCR 501 from Anton-Paar. The melt flow behavior of ABS/SEBS filaments was determined. The morphology of the filaments was studied by scanning electron microscope and the mechanical (tensile and impact) properties, surface roughness and void content of printed samples were investigated.

Findings

The rheological results can accurately interpret what drives the morphology and mechanical properties’ changes in the blends. The impact strength, toughness, elongation-at-break and anisotropy in mechanical properties of ABS samples were improved concurrently by adding 40 Wt.% of SEBS. The optimal tensile properties of blend containing 40 Wt.% SEBS samples were obtained at −45°/+45° raster angle, 0.05 mm layer thickness and XYZ build orientation. Optimized samples showed an 890% increase in elongation compared to neat ABS. Also, the impact strength of ABS samples showed a 60% improvement by adding 40 Wt.% SEBS.

Originality/value

The paper simultaneously evaluates the effects of material composition and 3D printing parameters (layer thickness, raster angle and build orientation) on the rheology, morphology, mechanical properties and surface roughness. Also, a mechanical properties comparison between printed samples and their compression-molded counterpart was conducted.

Details

Rapid Prototyping Journal, vol. 26 no. 10
Type: Research Article
ISSN: 1355-2546

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