Three-Dimensional Simulation of Multiple-Line Laser Sintering of a Two-Component Metal Powder Layer on Top of Sintered Layers

2005 ◽  
Author(s):  
Tiebing Chen ◽  
Yuwen Zhang
Keyword(s):  
Laser Beam ◽  
Metal Powder ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Powder Layer ◽  
Metal Powders ◽  
Gaussian Laser Beam ◽  
Laser Beam Intensity ◽  
Multiple Line ◽  
Two Component

Multiple line laser scan sintering of a two-component metal powder layer on top of the sintered layers with a moving circular Gaussian laser beam is modeled numerically. The overlap between the adjacent scan lines to achieve enhanced bonding is taken into account. The binding between the newly sintered layer and existing sintered layers underneath through melting is also considered. The governing equation is formulated by a temperature-transforming model with partial shrinkage induced by melting considered. The liquid flow of the molten low melting point metal powders, which is driven by capillary and gravity forces, is formulated by Darcy’s law. The effects of the dominant processing parameters, including the moving laser beam intensity, scanning speed and number of the existing sintered layers underneath, on the shape of the heat affected zone (HAZ) are investigated. A parametric study is performed and the best combination of the processing parameters is recommended.

Three-Dimensional Modeling of Laser Sintering of a Two-Component Metal Powder Layer on Top of Sintered Layers

2006 ◽  
Vol 129 (3) ◽  
pp. 575-582 ◽  
Author(s):  
Tiebing Chen ◽  
Yuwen Zhang
Keyword(s):  
Metal Powder ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Powder Layer ◽  
Metal Powders ◽  
Three Dimensional Model ◽  
Scanning Velocity ◽  
Laser Beam Intensity ◽  
Two Component

A three-dimensional model of selective laser sintering of a two-component loose metal powder layer on top of previously sintered layers by a single-line laser scanning is presented. A temperature-transforming model is employed to model melting and resolidification accompanied by partial shrinkage during laser sintering. The heat losses at the top surface due to natural convection and radiation are taken into account. The liquid flow of the molten low-melting-point metal powders, which is driven by capillary and gravity forces, is also considered and formulated by using Darcy’s law. The effects of the dominant processing parameters, such as laser-beam intensity, scanning velocity, and number of the existing sintered layers underneath, are investigated.

Analysis and modeling of direct selective laser sintering of two-component metal powders

2005 ◽  
Author(s):  
◽  
Tiebing Chen
Keyword(s):  
Laser Beam ◽  
Selective Laser Sintering ◽  
Finite Thickness ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Powder Layer ◽  
Metal Powders ◽  
Gaussian Laser Beam ◽  
Scanning Velocity ◽  
Two Component

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Direct Selective Laser Sintering (SLS) is an emerging technology of Solid Freeform Fabrication (SFF) that 3-D parts are built from the metal-based powder bed with CAD data. A one-dimensional analytical model of melting in a two-component powder layer with finite thickness subjected to a constant heat flux heating and a two-dimensional numerical model of SLS of a two-component powder layer with a moving laser beam scanning were developed consecutively. Three-dimensional modeling of laser sintering of a two-component metal powder mixture under a moving Gaussian laser beam was investigated numerically at last. The effects of the moving heat source intensity, the scanning velocity, the thickness of the powder layer and the number of existing sintered layers underneath on the sintering depth, the configuration of the heat affected zone (HAZ) and the temperature distribution are discussed.

Three-Dimensional Modeling of Selective Laser Sintering of Two-Component Metal Powder Layers

2005 ◽  
Vol 128 (1) ◽  
pp. 299-306 ◽  
Author(s):  
Tiebing Chen ◽  
Yuwen Zhang
Keyword(s):  
Metal Powder ◽  
Continuous Wave ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Powder Layer ◽  
Metal Powders ◽  
Gaussian Laser Beam ◽  
Scanning Velocity ◽  
Three Dimensional Modeling

Laser sintering of a metal powder mixture that contains two kinds of metal powders with significantly different melting points under a moving Gaussian laser beam is investigated numerically. The continuous-wave laser-induced melting accompanied by shrinkage and resolidification of the metal powder layer are modeled using a temperature-transforming model. The liquid flow of the melted low-melting-point metal driven by capillary and gravity forces is also included in the physical model. The numerical results are validated by experimental results, and a detailed parametric study is performed. The effects of the moving heat source intensity, the scanning velocity, and the thickness of the powder layer on the sintering depth, the configuration of the heat affected zone, and the temperature distribution are discussed.

Partial Melting and Resolidification of Single-Component Metal Powder With a Moving Laser Beam

2005 ◽  
Author(s):  
Bin Xiao ◽  
Yuwen Zhang
Keyword(s):  
Melting Point ◽  
Laser Beam ◽  
Partial Melting ◽  
Metal Powder ◽  
Liquid Pool ◽  
Single Component ◽  
Solid Core ◽  
Metal Powders ◽  
Scanning Velocity ◽  
Laser Beam Intensity

Partial melting and resolidification of single-component metal powders with a moving laser beam is investigated numerically. Since laser processing of metal powder is a very rapid process, the liquid layer and solid core of a partially molten powder particle may not at thermal equilibrium and have different temperatures: the temperature of the liquid part is higher than the melting point, and the temperature of the solid core is below the melting point. Therefore, the local temperature of regions with partial molten particles is within a range of temperature adjacent to the melting point, instead of at the melting point. The partial melting of the metal powder is also accompanied by shrinkage that drives out the gas in the powder bed and the powder structure is supported by the solid core of the partially melted powder particles. Melting with shrinkage and resolidification are described using a temperature transforming model. The convection driven by capillary and gravity forces in the melting liquid pool is formulated by using Darcy’s law. The effects of laser beam intensity and scanning velocity on the shape and size of the heat affected zone and molten pool are investigated.

Melting and Resolidification of a Two-Component Metal Powder Layer Heated by a Moving Gaussian Heat Source

2003 ◽  
Author(s):  
Tiebing Chen ◽  
Yuwen Zhang
Keyword(s):  
Steady State ◽  
Heat Source ◽  
Coordinate System ◽  
Metal Powder ◽  
Powder Layer ◽  
Moving Heat Source ◽  
Metal Powders ◽  
Melting Points ◽  
Scanning Velocity ◽  
Two Component

Melting and resolidification of a subcooled mixed metal powder layer that contains a mixture of two metal powders with significantly different melting points heated by a moving Gaussian heat source is investigated numerically. The phase change is modeled using a temperature-transforming model and shrinkage induced by melting is also taken into account. The problem appears to be steady-state since it is formulated in a coordinate system moving with the Gaussian heat source and the size of the powder is much larger than that of the heat source. The results show that the powder layer thickness, moving heat source intensity and scanning velocity have significant effects on the sintering depth.

Influence of Thermal Deformations in the Solid Laser Medium on the Emitted Radiation Parameters

2005 ◽  
Vol 219 (8) ◽  
pp. 823-827
Author(s):  
O Donţu ◽  
S Ganatsios ◽  
D Duminica
Keyword(s):  
Laser Beam ◽  
Radial Distribution ◽  
Thermal Deformation ◽  
Processing Parameters ◽  
Beam Intensity ◽  
Laser Medium ◽  
Laser Beam Intensity ◽  
Active Laser ◽  
Thermal Deformations ◽  
Active Laser Medium

The paper presents some remarks about the way in which the thermal deformation in the solid active laser medium influences the radial distribution of the emitted laser beam intensity, implicitly the processing parameters.

scholarly journals Uncertainties Induced by Processing Parameter Variation in Selective Laser Melting of Ti6Al4V Revealed by In-Situ X-ray Imaging

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 530
Author(s):  
Zachary A. Young ◽  
Meelap M. Coday ◽  
Qilin Guo ◽  
Minglei Qu ◽  
S. Mohammad H. Hojjatzadeh ◽  
...  
Keyword(s):  
Laser Beam ◽  
Selective Laser Melting ◽  
Small Deviation ◽  
Processing Parameters ◽  
Powder Layer ◽  
Beam Size ◽  
Processing Parameter ◽  
Laser Melting ◽  
Melt Pool

Selective laser melting (SLM) additive manufacturing (AM) exhibits uncertainties, where variations in build quality are present despite utilizing the same optimized processing parameters. In this work, we identify the sources of uncertainty in SLM process by in-situ characterization of SLM dynamics induced by small variations in processing parameters. We show that variations in the laser beam size, laser power, laser scan speed, and powder layer thickness result in significant variations in the depression zone, melt pool, and spatter behavior. On average, a small deviation of only ~5% from the optimized/reference laser processing parameter resulted in a ~10% or greater change in the depression zone and melt pool geometries. For spatter dynamics, small variation (10 μm, 11%) of the laser beam size could lead to over 40% change in the overall volume of the spatter generated. The responses of the SLM dynamics to small variations of processing parameters revealed in this work are useful for understanding the process uncertainties in the SLM process.

Effect of processing parameters on forming defects during selective laser melting of AlSi10Mg powder

2020 ◽  
Vol 26 (5) ◽  
pp. 871-879 ◽  
Author(s):  
Haihua Wu ◽  
Junfeng Li ◽  
Zhengying Wei ◽  
Pei Wei
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Argon Pressure ◽  
Powder Layer ◽  
Laser Melting ◽  
Content Type ◽  
Scan Speed ◽  
Forming Defects

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%.

Laser-Beam Fusion of Predeposited Metal Powder for Layered Manufacturing: Modeling, Simulation, and Experiment

1998 ◽  
Author(s):  
Vladimir Yevko ◽  
Gene Zak ◽  
Chul B. Park ◽  
Tom W. Coyle ◽  
Beno Benhabib
Keyword(s):  
Laser Beam ◽  
Metal Powder ◽  
Process Parameters ◽  
Powder Layer ◽  
Geometrical Properties ◽  
Metal Parts ◽  
Process Simulations ◽  
Simulation And Experiment ◽  
Laser Beam Scanning ◽  
Good Agreement

Abstract Current commercial Rapid Prototyping (RP) 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 create functional fully-dense metal parts without hard tooling. A possible solution to this problem is direct layered Rapid Manufacturing (RM) of such parts, for example, via laser-beam fusion of the metal powder. The RM process proposed herein is based on this approach. It involves selective laser-beam 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 proposed RM process, 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.

Effects of the Processing Parameters on the Forming Quality of Stainless Steel Parts by Selective Laser Melting

2011 ◽  
Vol 189-193 ◽  
pp. 3668-3671 ◽  
Author(s):  
Qing Song Wei ◽  
Xiao Zhao ◽  
Li Wang ◽  
Rui Di Li ◽  
Jie Liu ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Selective Laser Melting ◽  
Molten Pool ◽  
Laser Power ◽  
Single Layer ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Powder Layer ◽  
Laser Melting

Selective Laser Melting (SLM) can produce high-performance metal parts with complex structures. However, it’s difficult to control the processing parameters, because many factors involves. From the perspective of the molten pool, the study focuses on the effects of processing parameters, including scanning speed, laser power, scanning space, layer thickness, and scanning strategies, on the surface quality, the balling effect, the density of SLM parts, by conducting experiments of single track, single layer and block forming. The results show that the quality of the molten pool is affected by laser power and scanning speed. Scanning drove in the strategy of “jumping and turning”，a smooth surface and a less balling effect will be obtained. The thicker the powder layer is, the lower density will be obtained. The optimal parameters from series of experiments are: laser power of 98W; scanning speed of 90mm/s; scanning space of 0.07mm; layer thickness of 0.1mm; and scanning strategy of “jumping and turning”.

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