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Article
Publication date: 18 April 2017

Swee Leong Sing, Wai Yee Yeong, Florencia Edith Wiria, Bee Yen Tay, Ziqiang Zhao, Lin Zhao, Zhiling Tian and Shoufeng Yang

This paper aims to provide a review on the process of additive manufacturing of ceramic materials, focusing on partial and full melting of ceramic powder by a high-energy…

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Abstract

Purpose

This paper aims to provide a review on the process of additive manufacturing of ceramic materials, focusing on partial and full melting of ceramic powder by a high-energy laser beam without the use of binders.

Design/methodology/approach

Selective laser sintering or melting (SLS/SLM) techniques are first introduced, followed by analysis of results from silica (SiO2), zirconia (ZrO2) and ceramic-reinforced metal matrix composites processed by direct laser sintering and melting.

Findings

At the current state of technology, it is still a challenge to fabricate dense ceramic components directly using SLS/SLM. Critical challenges encountered during direct laser melting of ceramic will be discussed, including deposition of ceramic powder layer, interaction between laser and powder particles, dynamic melting and consolidation mechanism of the process and the presence of residual stresses in ceramics processed via SLS/SLM.

Originality/value

Despite the challenges, SLS/SLM still has the potential in fabrication of ceramics. Additional research is needed to understand and establish the optimal interaction between the laser beam and ceramic powder bed for full density part fabrication. Looking into the future, other melting-based techniques for ceramic and composites are presented, along with their potential applications.

Details

Rapid Prototyping Journal, vol. 23 no. 3
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 10 July 2020

Juan Daniel Trejos, Luis Arturo Reyes, Carlos Garza, Patricia Zambrano and Omar Lopez-Botello

An experimental and numerical study of thermal profiles of 316 L stainless steel during selective laser melting (SLM) was developed. This study aims to present a novel…

Abstract

Purpose

An experimental and numerical study of thermal profiles of 316 L stainless steel during selective laser melting (SLM) was developed. This study aims to present a novel approach to determine the significance and contribution of thermal numerical modeling enhancement factors of SLM.

Design/methodology/approach

Surface and volumetric heat models were proposed to compare the laser interaction with the powder bed and substrate, considering the powder size, absorptance and propagation of the laser energy through the effective depth of the metal layer. The approach consists in evaluating the contribution of the thermal conductivity anisotropic enhancement factors to establish the factors that minimized the error of the predicted results vs the experimental data.

Findings

The level of confidence of the carried-out analysis is of 97.8% for the width of the melt pool and of 99.8% for the depth of the melt pool. The enhancement factors of the y and z spatial coordinates influence the most in the predicted melt pool geometry.

Research limitations/implications

Nevertheless, the methodology presented in this study is not limited to 316 L stainless steel and can be applied to any metallic material used for SLM processes.

Practical implications

This study is focused on 316 L stainless steel, which is commonly used in SLM and is considered a durable material for high-temperature, high-corrosion and high-stress situations.

Social implications

The additive manufacturing (AM) technology is a relatively new technology becoming global. The AM technology may have health benefits when compared to the conventional industrial processes, as the workers avoid extended periods of exposure present in conventional manufacturing.

Originality/value

This study presents a novel approach to determine the significance and contribution of thermal numerical modeling enhancement factors of SLM. It was found that the volumetric heat model and anisotropic enhancement thermal approaches used in the present research, had a good agreement with experimental results.

Details

Rapid Prototyping Journal, vol. 26 no. 9
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 28 January 2020

Haihua Wu, Junfeng Li, Zhengying Wei and Pei Wei

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of…

Abstract

Purpose

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of ambient argon pressure and laser scanning speed on the particles splash during the AlSi10Mg powder bed laser melting.

Design/methodology/approach

Based on the discrete element method (DEM), a 3D model of random distribution of powder particles was established, and the 3D free surface of SLM forming process was dynamically tracked by the volume of fluid, where a Gaussian laser beam acts as the energy source melting the powder bed. Through the numerical simulation and process experimental research, the effect of the applied laser power and scanning speed on the operating laser melting temperature was studied.

Findings

The process stability has a fundamental role in the porosity formation, which is process-dependent. The effect of the processing conditions on the process stability and the resultant forming defects were clarified.

Research limitations/implications

The results shows that the pores were the main defects present in the SLM-processed AlSi10Mg sample, which decreases the densification level of the sample.

Practical implications

The optimal processing parameters (argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm ) applied during laser melting can improve the quality of selective laser melting of AlSi10Mg,

Social implications

It can provide a technological support for 3D printing.

Originality/value

Based on the analysis of the pore and balling formation mechanisms, the optimal processing parameters have been obtained, which were argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm. Then, a near-fully dense sample free of any apparent pores on the cross-sectional microstructure was produced by SLM, wherein the relative density of the as-built samples is larger than 97.5%.

Details

Rapid Prototyping Journal, vol. 26 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 18 January 2016

Maria Doubenskaia, Sergey Grigoriev, Ivan Zhirnov and Igor Smurov

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…

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 μm), hatch distance (60-1,000 μm) 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.

Details

Rapid Prototyping Journal, vol. 22 no. 1
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 27 September 2011

Reimund Neugebauer, Bernhard Müller, Mathias Gebauer and Thomas Töppel

The purpose of this paper is to show the innovative approach of manufacturing filigree and highly complex components by means of laser beam melting.

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Abstract

Purpose

The purpose of this paper is to show the innovative approach of manufacturing filigree and highly complex components by means of laser beam melting.

Design/methodology/approach

The paper describes the unique geometric freedom of the laser beam melting technology and its possibility of quick, tool‐less production of complex components allow the manufacturing of functionally superior components in a short time.

Findings

Principally concludes the following: additive manufacturing proved to give superior properties to the component compared to conventional manufacturing methods.

Originality/value

This study provides context for the development and manufacturing of an individual heat‐transfer component for an electric‐driven formula race car.

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Article
Publication date: 21 March 2016

A.R. Vinod, C.K. Srinivasa, R. Keshavamurthy and P.V. Shashikumar

This paper aims to focus on reducing lead-time and energy consumption for laser-based metal deposition of Inconel-625 superalloy and to investigate the effect of process…

Abstract

Purpose

This paper aims to focus on reducing lead-time and energy consumption for laser-based metal deposition of Inconel-625 superalloy and to investigate the effect of process parameters on microstructure, density, surface roughness, dimensional accuracy and microhardness.

Design/methodology/approach

Inconel material was deposited on steel substrate by varying process parameters such as laser power, laser scan speed and powder flow rate. The deposited parts were characterized for their density, surface roughness, dimensional accuracy and microhardness.

Findings

The study reveals that with increase in laser power, laser scan speed and powder flow rate, there was an increase in density, surface roughness values and microhardness of the deposits, while there was a decrease in dimensional accuracy, deposition time and energy consumption.

Practical implications

The results of this study can be useful in fabrication of Inconel components by laser-based metal deposition process, and the methodology can be expanded to other materials to reduce the lead-time and energy consumption effectively.

Originality/value

The present study gives an understanding of effect of process parameters on density, surface roughness, dimensional accuracy, microhardness, deposition time and energy consumption for laser-based metal deposition of Inconel-625.

Details

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

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Article
Publication date: 1 December 1998

V. Yevko, C.B. Park, G. Zak, T.W. Coyle and B. Benhabib

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to…

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Abstract

Current commercial rapid prototyping systems can be used for fabricating layered models for subsequent creation of fully‐dense metal parts using investment casting. Due to increased demand for shortened product development cycles however, there exists a demand to rapidly fabricate functional fully‐dense metal parts without hard tooling. A possible solution to this problem is direct layered rapid manufacturing of such parts, for example, via laserbeam fusion of the metal powder. The rapid manufacturing process discussed herein is based on this approach. It involves selective laserbeam scanning of a predeposited metal‐powder layer, forming fully‐dense claddings as the basic building block of individual layers. This paper specifically addresses only one of the fundamental issues of the rapid manufacturing process under investigation at the University of Toronto, namely the fabrication of single claddings. Our theoretical investigation of the influence of the process parameters on cladding’s geometrical properties employed thermal modeling and computer process simulation. Numerous experiments, involving fabrication of single claddings, were also carried out with varying process parameters. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.

Details

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

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Article
Publication date: 1 February 1997

Chris Williams

Looks at the various applications of the CO2 gas laser in industrial material processing. Describes how the CO2 laser beam interacts with particular materials and…

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1012

Abstract

Looks at the various applications of the CO2 gas laser in industrial material processing. Describes how the CO2 laser beam interacts with particular materials and highlights the laser system configuration, system characteristics and attributes. Details CO2 laser cutting, welding and surface modification and briefly touches on some emerging aerospace application areas.

Details

Aircraft Engineering and Aerospace Technology, vol. 69 no. 1
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 31 July 2009

Lino Costa and Rui Vilar

The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense…

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4211

Abstract

Purpose

The purpose of this paper is to review the state of the art of laser powder deposition (LPD), a solid freeform fabrication technique capable of fabricating fully dense functional items from a wide range of common engineering materials, such as aluminum alloys, steels, titanium alloys, nickel superalloys and refractory materials.

Design/methodology/approach

The main R&D efforts and the major issues related to LPD are revisited.

Findings

During recent years, a worldwide series of R&D efforts have been undertaken to develop and explore the capabilities of LPD and to tap into the possible cost and time savings and many potential applications that this technology offers.

Originality/value

These R&D efforts have produced a wealth of knowledge, the main points of which are highlighted herein.

Details

Rapid Prototyping Journal, vol. 15 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 17 October 2017

Sanjay Kumar and Aleksander Czekanski

WC-Co is a well-known material for conventional tooling but is not yet commercially available for additive manufacturing. Processing it by selective laser sintering (SLS…

Abstract

Purpose

WC-Co is a well-known material for conventional tooling but is not yet commercially available for additive manufacturing. Processing it by selective laser sintering (SLS) will pave the way for its commercialization and adoption.

Design/methodology/approach

It is intended to optimize process parameters (laser power, hatch spacing, scan speed) by fabricating a bigger part (minimum size of 10 mm diameter and 5 mm height). Microstructural analysis, EDX and hardness testing is used to study effects of process parameters. Optimized parameter is ascertained after fabricating 49 samples in preliminary experiment, 27 samples in pre-final experiment and 9 samples in final experiment.

Findings

Higher laser power gives rise to cracks and depletion of cobalt while higher scan speed increases porosity. Higher hatch spacing is responsible for delamination and displacement of parts. Optimized parameters are 270 W laser power, 500 mm/s scan speed, 0.04 mm layer thickness, 0.04 mm hatch spacing (resulting in energy density of 216 J/mm3) and 200°C powder bed temperature. A part comprising of small hole of 2 mm diameter, thin cylindrical pin of 0.5 mm diameter and thin wall of 2 mm width bent up to 30° angle to the base plate is fabricated. In order to calculate laser energy density, a new equation is introduced which takes into account both beam diameter and hatch spacing unlike old equation does. In order to calculate laser energy density, a new equation is formulated which takes into account both beam diameter and hatch spacing unlike old equation does. WC was not completely melted as intended giving rise to partial melting-type binding mechanism. This justified the name SLS for process in place of SLM (Selective Laser Melting).

Research limitations/implications

Using all possible combination of parameters plus heating the part bed to maximum shows limitation of state-of-the-art commercial powder bed fusion machine for shaping hardmetal consisting of high amount of WC (83 wt. per cent).

Practical implications

The research shows that microfeatures could be fabricated using WC-Co which will herald renewed interest in investigating hardmetals using SLS for manufacturing complex hard tools, molds and wear-resistance parts.

Originality/value

This is the first time micro features are successfully fabricated using WC-Co without post-processing (infiltration, machining) and without the help of additional binding material (such as Cu, Ni, Fe).

Details

Rapid Prototyping Journal, vol. 23 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

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