| 1. |
- Doubenskaia, Maria, et al.
(author)
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Parametric analysis of SLM using comprehensive optical monitoring
- 2016
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In: Rapid prototyping journal. - : Emerald Group Publishing Limited. - 1355-2546 .- 1758-7670. ; 22:1, s. 40-50
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Journal article (peer-reviewed)abstract
- Purpose - This paper aims to propose methods for on-line monitoring and process quality assurance of Selective Laser Melting (SLM) technology as a competitive advantage to enhance its implementation into modern manufacturing industry.Design/methodology/approach - Monitoring of thermal emission from the laser impact zone was carried out by an originally developed pyrometer and a charge-coupled device (CCD) camera which were integrated with the optical system of the PHENIX PM-100 machine. Experiments are performed with variation of the basic process parameters such as powder layer thickness (0-120 mu m), hatch distance (60-1,000 mu m) and fabrication strategy (the so-called "one-zone" and "two-zone").Findings - The pyrometer signal from the laser impact zone and the 2D temperature mapping from HAZ are rather sensible to variation of high-temperature phenomena during powder consolidation imposed by variation of the operational parameters.Research limitations/implications - Pyrometer measurements are in arbitrary units. This limitation is due to the difficulty to integrate diagnostic tools into the optical system of a commercial SLM machine.Practical implications - Enhancement of SLM process stability and efficiency through comprehensive optical diagnostics and on-line control.Originality/value - High-temperature phenomena in SLM were monitored coaxially with the laser beam for variation of several operational parameters.
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| 2. |
- Ek, Rebecca, 1985-, et al.
(author)
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The Effect of EBM Process Parameters upon Surface Roughness
- 2016
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In: Rapid prototyping journal. - 1355-2546 .- 1758-7670. ; 22:3, s. 495-503
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Journal article (peer-reviewed)abstract
- Purpose-The surface roughness of products manufactured using the additive manufacturing (AM) technology of electron beam melting (EBM) has a special characteristic. Different product applications can demand rougher or finer surface structure, so the purpose of this study is to investigate the process parameters of EBM to find out how they affect surface roughness. Design/methodology/approach-EBM uses metal powder to manufacture metal parts. A design of experiment plan was used to describe the effects of the process parameters on the average surface roughness of vertical surfaces. Findings-The most important electron beam setting for surface roughness, accorDing to this study, is a combination of speed and current in the contours. The second most important parameter is contour offset. The interaction between the number of contours and contour offset also appears to be important, as it shows a much higher probability of being active than any other interaction. The results show that the line offset is not important when using contours. Research limitations/implications-This study examined contour offset, number of contours, speed in combination with current and line offset, which are process parameters controlling the electron beam. Practical implications-The surface properties could have an impact on the product's performance. A reduction in surface processing will not only save time and money but also reduce the environmental impact. Originality/value-Surface properties are important for many products. New themes containing process parameters have to be developed when introducing new materials to EBM manufacturing. During this process, it is very important to understand how the electron beam affects the melt pool.
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| 3. |
- Eutionnat-Diffo, Prisca, 1992-, et al.
(author)
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Optimization of adhesion of poly lactic acid 3D printed onto polyethylene terephthalate wovenfabrics through modelling using textile properties
- 2019
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In: Rapid prototyping journal. - 1355-2546 .- 1758-7670.
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Journal article (peer-reviewed)abstract
- PurposeThis paper aims to evaluate and simulate the impact of the build platform temperature of the three-dimensional (3D) printer, the structure and heat transfer of textiles on the adhesion and durability after washing properties of 3D printed polymer onto textile materials using thin layers of conductive and non-conductive extruded poly lactic acid monofilaments (PLA) deposited on polyethylene terephthalate (PET) woven fabrics through fused deposition modeling (FDM) process.Design/methodology/approachPrior to FDM process, thermal conductivity, surface roughness and mean pore size of PET woven fabrics were assessed using the “hot disk,” the profilometer and the capillary flow porometry methods, respectively. After the FDM process, the adhesion and durability after the washing process properties of the materials were determined and optimized based on reliable statistical models connecting those properties to the textile substrate properties such as surface roughness, mean pore size and thermal conductivity.FindingsThe main findings point out that higher roughness coefficient and mean pore size and lower thermal conductivity of polyester woven textile materials improve the adhesion properties and the build platform presents a quadratic effect. Additionally, the adhesion strength decreases by half after the washing process and rougher and more porous textile structures demonstrate better durability. These results are explained by the surface topography of textile materials that define the anchorage areas between the printed layer and the textiles.Originality/valueThis study is for great importance in the development of smart textiles using FDM process as it presents unique and reliable models used to optimize adhesion resistance of 3D printed PLA primary layer onto PET textiles.
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| 4. |
- Farré-Lladós, Josep, et al.
(author)
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The use of Rapid Prototyping techniques (RPT) to manufacture micro channels suitable for high operation pressures and µPIV
- 2016
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In: Rapid prototyping journal. - 1355-2546 .- 1758-7670. ; 22:1, s. 67-76
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Journal article (peer-reviewed)abstract
- Purpose– This paper aims to present a new methodology to manufacture micro-channels suitable for high operating pressures and micro particle image velocimetry (μPIV) measurements using a rapid-prototyping high-resolution 3D printer. This methodology can fabricate channels down to 250 μm and withstand pressures of up to 5 ± 0.2 MPa. The manufacturing times are much shorter than in soft lithography processes. Design/methodology/approach– The novel manufacturing method developed takes advantage of the recently improved resolution in 3D printers to manufacture an rapid prototyping technique part that contains the hose connections and a micro-channel useful for microfluidics. A method to assemble one wall of the micro-channel using UV curable glue with a glass slide is presented – an operation required to prepare the channel for μPIV measurements. Once built, the micro-channel has been evaluated when working under pressure and the grease flow behavior in it has been measured using μPIV. Furthermore, the minimum achievable channels have been defined using a confocal microscopy study. Findings– This technique is much faster than previous micro-manufacturing techniques where different steps were needed to obtain the micro-machined parts. However, due to current 3D printers ' resolutions (around 50 μm) and according to the experimental results, channels smaller than 250-μm2 cross-section should not be used to characterize fluid flow behaviors, as inaccuracies in the channel boundaries can deeply affect the fluid flow behavior. Practical implications– The present methodology is developed due to the need to validate micro-channels using μPIV to lubricate critical components (bearings and gears) in wind turbines. Originality/value– This novel micro-manufacturing technique overcomes current techniques, as it requires less manufacturing steps and therefore it is faster and with less associated costs to manufacture micro-channels down to 250-μm2 cross-section that can withstand pressures higher than 5 MPa that can be used to characterize microfluidic flow behavior using μPIV.
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| 5. |
- Goulas, Athanasios, et al.
(author)
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3D printing with moondust
- 2016
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In: Rapid prototyping journal. - Bingley : Emerald Group Publishing Limited. - 1355-2546 .- 1758-7670. ; 22:6, s. 864-870
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Journal article (peer-reviewed)abstract
- Purpose - The purpose of this paper is to investigate the effect of the main process parameters of laser melting (LM) type additive manufacturing (AM) on multi-layered structures manufactured from JSC-1A Lunar regolith (Moondust) simulant powder. Design/methodology/approach - Laser diffraction technology was used to analyse and confirm the simulant powder material particle sizes and distribution. Geometrical shapes were then manufactured on a Realizer SLM™ 100 using the simulant powder. The laser-processed samples were analysed via scanning electron microscopy to evaluate surface and internal morphologies, X-ray fluorescence spectroscopy to analyse the chemical composition after processing, and the samples were mechanically investigated via Vickers micro-hardness testing. Findings - A combination of process parameters resulting in an energy density value of 1.011 J/mm2 allowed the successful production of components directly from Lunar regolith simulant. An internal relative porosity of 40.8 per cent, material hardness of 670 ±11 HV and a dimensional accuracy of 99.8 per cent were observed in the fabricated samples. Originality/value - This research paper is investigating the novel application of a powder bed fusion AM process category as a potential on-site manufacturing approach for manufacturing structures/components out of Lunar regolith (Moondust). It was shown that this AM process category has the capability to directly manufacture multi-layered parts out of Lunar regolith, which has potential applicability to future moon colonization. © Emerald Group Publishing Limited.
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| 6. |
- Kantaros, Antreas, et al.
(author)
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3D printing technology in musical instrument research : reviewing the potential
- 2018
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In: Rapid Prototyping Journal. - 1355-2546. ; 24:9, s. 1511-1523
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Journal article (peer-reviewed)abstract
- Purpose: This paper aims to discuss additive manufacturing (AM) in the context of applications for musical instruments. It examines the main AM technologies used in musical instruments, goes through a history of musical applications of AM and raises the questions about the application of AM to create completely new wind instruments that would be impossible to produce with conventional manufacturing. Design/methodology/approach: A literature research is presented which covers a historical application of AM to musical instruments and hypothesizes on some potential new applications. Findings: AM has found extensive application to create conventional musical instruments with unique aesthetics designs. It’s true potential to create entirely new sounds, however, remains largely untapped. Research limitations/implications: More research is needed to truly assess the potential of additive manufacturing to create entirely new sounds for musical instrument. Practical implications: The application of AM in music could herald an entirely new class of musical instruments with unique sounds. Originality/value: This study highlights musical instruments as an unusual application of AM. It highlights the potential of AM to create entirely new sounds, which could create a whole new class of musical instruments.
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| 7. |
- Li, Ji, et al.
(author)
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Enabling internal electronic circuitry within additively manufactured metal structures – The effect and importance of inter-laminar topography
- 2018
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In: Rapid Prototyping Journal. - Bingley : Emerald Group Publishing Limited. - 1355-2546 .- 1758-7670. ; 24:1, s. 204-213
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Journal article (peer-reviewed)abstract
- Purpose – This paper aims to explore the potential of ultrasonic additive manufacturing (UAM) to incorporate the direct printing of electrical materials and arrangements (conductors and insulators) at the interlaminar interface of parts during manufacture to allow the integration of functional and optimal electrical circuitries inside dense metallic objects without detrimental effect on the overall mechanical integrity. This holds promise to release transformative device functionality and applications of smart metallic devices and products. Design/methodology/approach – To ensure the proper electrical insulation between the printed conductors and metal matrices, an insulation layer with sufficient thickness is required to accommodate the rough interlaminar surface which is inherent to the UAM process. This in turn increases the total thickness of printed circuitries and thereby adversely affects the integrity of the UAM part. A specific solution is proposed to optimise the rough interlaminar surface through deforming the UAM substrates via sonotrode rolling or UAM processing. Findings – The surface roughness (Sa) could be reduced from 4.5 to 4.1 mm by sonotrode rolling and from 4.5 to 0.8 mm by ultrasonic deformation. Peel testing demonstrated that sonotrode-rolled substrates could maintain their mechanical strength, while the performance of UAM-deformed substrates degraded under same welding conditions (approximately 12 per cent reduction compared with undeformed substrates). This was attributed to the work hardening of deformation process which was identified via dual-beam focussed ion beam–scanning electron microscope investigation. Originality/value – The sonotrode rolling was identified as a viable methodology in allowing printed electrical circuitries in UAM. It enabled a decrease in the thickness of printed electrical circuitries by ca. 25 per cent.
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| 8. |
- Näsström, Jonas, et al.
(author)
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Measuring the effects of a laser beam on melt pool fluctuation in arc additive manufacturing
- 2019
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In: Rapid prototyping journal. - : Emerald Group Publishing Limited. - 1355-2546 .- 1758-7670. ; 25:3, s. 488-495
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Journal article (peer-reviewed)abstract
- PurposeThe steadily growing popularity of additive manufacturing (AM) increases the demand for understanding fundamental behaviors of these processes. High-speed imaging (HSI) can be a useful tool to observe these behaviors, but many studies only present qualitative analysis. The purpose of this paper is to propose an algorithm-assisted method as an intermediate to rapidly quantify data from HSI. Here, the method is used to study melt pool surface profile movement in a cold metal transfer-based (CMT-based) AM process, and how it changes when the process is augmented with a laser beam.Design/methodology/approachSingle-track wide walls are generated in multiple layers using only CMT, CMT with leading and with trailing laser beam while observing the processes using HSI. The studied features are manually traced in multiple HSI frames. Algorithms are then used for sorting measurement points and generating feature curves for easier comparison.FindingsUsing this method, it is found that the fluctuation of the melt surface in the chosen CMT AM process can be reduced by more than 35 per cent with the addition of a laser beam trailing behind the arc. This indicates that arc and laser can be a viable combination for AM.Originality/valueThe suggested quantification method was used successfully for the laser-arc hybrid process and can also be applied for studies of many other AM processes where HSI is implemented. This can help fortify and expand the understanding of many phenomena in AM that were previously too difficult to measure.
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| 9. |
- Weiss, Benjamin, et al.
(author)
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A process for estimating minimum feature size in selective laser sintering
- 2018
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In: Rapid Prototyping Journal. - 1355-2546. ; 24:2, s. 436-440
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Journal article (peer-reviewed)abstract
- Purpose: Manufacturer specifications for the resolution of an additive manufacturing (AM) machine can be ten times smaller (more optimistic) than the actual size of manufacturable features. Existing methods used to establish a manufacturable design rule-set are conservative piecewise-constant approximations. This paper aims to evaluate the effectiveness of a first-order model for producing improved design rule-sets for feature manufacturability, accounting for process variation. Design/methodology/approach: A framework is presented which uses an interpolation method and a statistical model to estimate the minimum size for a wide range of features from a set of iterative experiments. Findings: For an SLS process, using this approach improves the accuracy and reliability of minimum feature size estimates for a wider variety of features than assessed by most existing test artifacts. Research limitations/implications: More research is needed to provide better interpolation models, broaden applicability and account for additional geometric and process parameters which significantly impact the results. This research focuses on manufacturability and does not address dimensional accuracy of the features produced. Practical implications: An application to the design of thin channels in a prosthetic hand shows the utility of the results in a real-world scenario. Originality/value: This study is among the first to investigate statistical variation of “pass/fail” features in AM process characterization, propose a means of estimating minimum feature sizes for shapes not directly tested and incorporate a more efficient iterative experimental protocol.
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| 10. |
- Wiberg, Anton, et al.
(author)
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Design for additive manufacturing : a review of available design methods and software
- 2019
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In: Rapid prototyping journal. - : Emerald Group Publishing Limited. - 1355-2546 .- 1758-7670. ; 25:6, s. 1080-1094
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Research review (peer-reviewed)abstract
- PurposeThis paper aims to review recent research in design for additive manufacturing (DfAM), including additive manufacturing (AM) terminology, trends, methods, classification of DfAM methods and software. The focus is on the design engineer’s role in the DfAM process and includes which design methods and tools exist to aid the design process. This includes methods, guidelines and software to achieve design optimization and in further steps to increase the level of design automation for metal AM techniques. The research has a special interest in structural optimization and the coupling between topology optimization and AM.Design/methodology/approachThe method used in the review consists of six rounds in which literature was sequentially collected, sorted and removed. Full presentation of the method used could be found in the paper.FindingsExisting DfAM research has been divided into three main groups – component, part and process design – and based on the review of existing DfAM methods, a proposal for a DfAM process has been compiled. Design support suitable for use by design engineers is linked to each step in the compiled DfAM process. Finally, the review suggests a possible new DfAM process that allows a higher degree of design automation than today’s process. Furthermore, research areas that need to be further developed to achieve this framework are pointed out.Originality/valueThe review maps existing research in design for additive manufacturing and compiles a proposed design method. For each step in the proposed method, existing methods and software are coupled. This type of overall methodology with connecting methods and software did not exist before. The work also contributes with a discussion regarding future design process and automation.
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