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1 – 10 of over 36000Grazielle 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 selective laser…
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.
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Modupeola Dada, Patricia Popoola and Ntombi Mathe
This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current potential…
Abstract
Purpose
This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current potential alternatives to nickel superalloys for gas turbine applications. Understandings of the laser surface modification techniques of the HEA are discussed whilst future recommendations and remedies to manufacturing challenges via laser are outlined.
Design/methodology/approach
Materials used for high-pressure gas turbine engine applications must be able to withstand severe environmentally induced degradation, mechanical, thermal loads and general extreme conditions caused by hot corrosive gases, high-temperature oxidation and stress. Over the years, Nickel-based superalloys with elevated temperature rupture and creep resistance, excellent lifetime expectancy and solution strengthening L12 and γ´ precipitate used for turbine engine applications. However, the superalloy’s density, low creep strength, poor thermal conductivity, difficulty in machining and low fatigue resistance demands the innovation of new advanced materials.
Findings
HEAs is one of the most frequently investigated advanced materials, attributed to their configurational complexity and properties reported to exceed conventional materials. Thus, owing to their characteristic feature of the high entropy effect, several other materials have emerged to become potential solutions for several functional and structural applications in the aerospace industry. In a previous study, research contributions show that defects are associated with conventional manufacturing processes of HEAs; therefore, this study investigates new advances in the laser-based manufacturing and surface modification techniques of HEA.
Research limitations/implications
The AlxCoCrCuFeNi HEA system, particularly the Al0.5CoCrCuFeNi HEA has been extensively studied, attributed to its mechanical and physical properties exceeding that of pure metals for aerospace turbine engine applications and the advances in the fabrication and surface modification processes of the alloy was outlined to show the latest developments focusing only on laser-based manufacturing processing due to its many advantages.
Originality/value
It is evident that high entropy materials are a potential innovative alternative to conventional superalloys for turbine engine applications via laser additive manufacturing.
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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…
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.
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Kura Alemayehu Beyene and Soliyana Gebeyaw
Friction is considered to be one property of cloth that has considerable importance in the fields of both technological and subjective assessment for surface properties of textile…
Abstract
Purpose
Friction is considered to be one property of cloth that has considerable importance in the fields of both technological and subjective assessment for surface properties of textile fabrics. The purpose of this study is to investigate the affective aspects of yarn and fabric structural parameters on the behavior of surface friction of plain woven fabrics.
Design/methodology/approach
In this study, nine varieties of half-bleached cotton plain-woven fabrics with three weft yarn count (tex) and three weft thread density (ppc) are produced and will be examined for their frictional characteristics. The surface frictional properties of plain-woven fabrics were measured by using Kawabata (KES-Fb4) testing instrument. The ANOVA analysis is used to determine how yarn (count) and fabric (density) structural parameters does influence the surface friction properties of the fabrics. Also, the interaction effects between the factors (count and density) on the response variable (surface friction) of plain-woven fabrics.
Findings
The findings of this study revealed that the effects of weft yarn count and pick-density have statistically significant on the frictional behavior of the fabric surface properties at a 95% confidence interval. Thus, weft yarn count has a positive correlation with both coefficient of friction (MIU) and mean deviation of coefficient of friction (MMD) on frictional behavior of the fabric surface properties. On the other hand, pick density has a negative correlation with both MIU and MMD on frictional behavior of the fabric surface properties. The weft count, pick density and their interactions (Count X Density) have multicollinearity in the experiment term because the variance inflation factor values were greater than one.
Originality/value
The findings of this study can be routinely used across the textile industries and laboratories to provide a fundamental understanding regarding the surface frictional properties of the woven fabric for different end applications concerning the yarn structural parameters and fabric structural parameters. And the relationship of count and density with surface friction of plain woven fabrics.
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Mahyar Khorasani, Ian Gibson, Amir Hossein Ghasemi, Elahe Hadavi and Bernard Rolfe
The purpose of this study is, to compare laser-based additive manufacturing and subtractive methods. Laser-based manufacturing is a widely used, noncontact, advanced manufacturing…
Abstract
Purpose
The purpose of this study is, to compare laser-based additive manufacturing and subtractive methods. Laser-based manufacturing is a widely used, noncontact, advanced manufacturing technique, which can be applied to a very wide range of materials, with particular emphasis on metals. In this paper, the governing principles of both laser-based subtractive of metals (LB-SM) and laser-based powder bed fusion (LB-PBF) of metallic materials are discussed and evaluated in terms of performance and capabilities. Using the principles of both laser-based methods, some new potential hybrid additive manufacturing options are discussed.
Design methodology approach
Production characteristics, such as surface quality, dimensional accuracy, material range, mechanical properties and applications, are reviewed and discussed. The process parameters for both LB-PBF and LB-SM were identified, and different factors that caused defects in both processes are explored. Advantages, disadvantages and limitations are explained and analyzed to shed light on the process selection for both additive and subtractive processes.
Findings
The performance of subtractive and additive processes is highly related to the material properties, such as diffusivity, reflectivity, thermal conductivity as well as laser parameters. LB-PBF has more influential factors affecting the quality of produced parts and is a more complex process. Both LB-SM and LB-PBF are flexible manufacturing methods that can be applied to a wide range of materials; however, they both suffer from low energy efficiency and production rate. These may be useful when producing highly innovative parts detailed, hollow products, such as medical implants.
Originality value
This paper reviews the literature for both LB-PBF and LB-SM; nevertheless, the main contributions of this paper are twofold. To the best of the authors’ knowledge, this paper is one of the first to discuss the effect of the production process (both additive and subtractive) on the quality of the produced components. Also, some options for the hybrid capability of both LB-PBF and LB-SM are suggested to produce complex components with the desired macro- and microscale features.
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A.B. Spierings, N. Herres and G. Levy
A recent study confirmed that the particle size distribution of a metallic powder material has a major influence on the density of a part produced by selective laser melting…
Abstract
Purpose
A recent study confirmed that the particle size distribution of a metallic powder material has a major influence on the density of a part produced by selective laser melting (SLM). Although it is possible to get high density values with different powder types, the processing parameters have to be adjusted accordingly, affecting the process productivity. However, the particle size distribution does not only affect the density but also the surface quality and the mechanical properties of the parts. The purpose of this paper is to investigate the effect of three different powder granulations on the resulting part density, surface quality and mechanical properties of the materials produced.
Design/methodology/approach
The scan surface quality and mechanical properties of three different particle size distributions and two layer thicknesses of 30 and 45 μm were compared. The scan velocities for the different powder types have been adjusted in order to guarantee a part density≥99.5 per cent.
Findings
By using an optimised powder material, a low surface roughness can be obtained. A subsequent blasting process can further improve the surface roughness for all powder materials used in this study, although this does not change the ranking of the powders with respect to the resulting surface quality. Furthermore, optimised powder granulations lead generally to improved mechanical properties.
Practical implications
The results of this study indicate that the particle size distribution influences the quality of AM metallic parts, produced by SLM. Therefore, it is recommended that any standardisation initiative like ASTM F42 should develop guidelines for powder materials for AM processes. Furthermore, during production, the granulation changes due to spatters. Appropriate quality systems have to be developed.
Originality/value
The paper clearly shows that the particle size distribution plays an important role regarding density, surface quality and resulting mechanical properties.
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Examines the fifthteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…
Abstract
Examines the fifthteenth 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.
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Examines the fourteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…
Abstract
Examines the fourteenth 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
Keywords
Examines the fifteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…
Abstract
Examines the fifteenth 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.
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Abdul Wahab Hashmi, Harlal Singh Mali and Anoj Meena
The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the…
Abstract
Purpose
The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.
Design/methodology/approach
There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.
Findings
In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.
Research limitations/implications
The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.
Originality/value
This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.
Graphical abstract of surface quality improvement methods
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