scholarly journals Experimental and numerical study of process parameters effects towards part quality and porosity during powder bed additive manufacturing processes.

2020 ◽  
Author(s):  
Subin Shrestha
Keyword(s):  
Additive Manufacturing ◽  
Process Parameters ◽  
Numerical Study ◽  
Manufacturing Processes ◽  
Powder Bed ◽  
Part Quality

Analysis of defect generation in Ti–6Al–4V parts made using powder bed fusion additive manufacturing processes

2014 ◽  
Vol 1-4 ◽  
pp. 87-98 ◽  
Author(s):  
Haijun Gong ◽  
Khalid Rafi ◽  
Hengfeng Gu ◽  
Thomas Starr ◽  
Brent Stucker
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Processes ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Defect Generation

scholarly journals Virtual Development of Process Parameters for Bulk Metallic Glass Formation in Laser-Based Powder Bed Fusion

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 450
Author(s):  
Johan Lindwall ◽  
Andreas Lundbäck ◽  
Jithin James Marattukalam ◽  
Anders Ericsson
Keyword(s):  
Additive Manufacturing ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Process Parameters ◽  
Glass Formation ◽  
Laser Power ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Scanning Strategies ◽  
Hatch Spacing

The development of process parameters and scanning strategies for bulk metallic glass formation during additive manufacturing is time-consuming and costly. It typically involves trials with varying settings and destructive testing to evaluate the final phase structure of the experimental samples. In this study, we present an alternative method by modelling to predict the influence of the process parameters on the crystalline phase evolution during laser-based powder bed fusion (PBF-LB). The methodology is demonstrated by performing simulations, varying the following parameters: laser power, hatch spacing and hatch length. The results are compared in terms of crystalline volume fraction, crystal number density and mean crystal radius after scanning five consecutive layers. The result from the simulation shows an identical trend for the predicted crystalline phase fraction compared to the experimental estimates. It is shown that a low laser power, large hatch spacing and long hatch lengths are beneficial for glass formation during PBF-LB. The absolute values show an offset though, over-predicted by the numerical model. The method can indicate favourable parameter settings and be a complementary tool in the development of scanning strategies and processing parameters for additive manufacturing of bulk metallic glass.

scholarly journals Laser powder bed fusion additive manufacturing of copper wicking structures: fabrication and capillary characterization

2021 ◽  
Author(s):  
Adnen Mezghani
Keyword(s):  
Additive Manufacturing ◽  
Performance Analysis ◽  
Heat Pipes ◽  
Manufacturing Processes ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Published Report ◽  
Secondary Manufacturing ◽  
Design Freedom

PurposeAn integral component in heat pipes (HPs) and vapor chambers (VCs) is a porous wicking structure. Traditional methods for manufacturing wicking structures within HPs and VCs involve secondary manufacturing processes and are generally limited to simple geometries. This work aims to leverage the unprecedented level of design freedom of laser powder bed fusion (LPBF) additive manufacturing (AM) to produce integrated wicking structures for HPs and VCs.Design/methodology/approachCopper wicking structures are fabricated through LPBF via partial sintering and via the formation of square, hexagonal and rectangular arrangements of micro-pins and micro-grooves, produced in multiple build directions. Wicks are characterized by conducting capillary performance analysis through the measurement of porosity, permeability and capillary rate-of-rise.FindingsCopper wicking structures were successfully fabricated with capillary performance, K/reff, ranging from 0.186–1.74 µm. The rectangular-arrangement micro-pin wick presented the highest performance.Originality/valueThis work represents the first published report on LPBF AM of copper wicking structures for HPs/VCs applications and represents foundational knowledge for fabricating complete assemblies of copper VCs and HPs through LPBF AM.

Hybride Fertigung mittels Laser-Strahlschmelzen/Hybrid manufacturing by laser-based powder bed fusion

2021 ◽  
Vol 111 (06) ◽  
pp. 363-367
Author(s):  
Lukas Langer ◽  
Matthias Schmitt ◽  
Georg Schlick ◽  
Johannes Schilp
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Processes ◽  
Complex Geometries ◽  
Hybrid Manufacturing ◽  
Powder Bed Fusion ◽  
Process Chain ◽  
Manufacturing Costs ◽  
Additive Fertigung ◽  
Powder Bed

Die additive Fertigung ermöglicht komplexe Geometrien und individualisierte Bauteile. Die hohen Material- und Fertigungskosten können ein Hindernis für einen wirtschaftlichen Einsatz sein. In der hybriden additiven Fertigung werden die Vorteile konventioneller sowie additiver Fertigungsverfahren kombiniert. Für eine weitere Steigerung der Wirtschaftlichkeit und Effizienz werden nichtwertschöpfende Schritte der Prozesskette identifiziert und Automatisierungsansätze entwickelt.   Additive manufacturing enables complex geometries and individualized components. However, high material and manufacturing costs can be a hindrance for economical use. Hybrid additive manufacturing combines the advantages of conventional with additive manufacturing processes. For a further increase in profitability and efficiency, non-value-adding steps in the process chain are identified and automation approaches developed.

scholarly journals An Overview of Additive Manufacturing Technologies—A Review to Technical Synthesis in Numerical Study of Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3895 ◽  
Author(s):  
Abbas Razavykia ◽  
Eugenio Brusa ◽  
Cristiana Delprete ◽  
Reza Yavari
Keyword(s):  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Powder Bed Fusion ◽  
Laser Melting ◽  
Powder Bed ◽  
Part Quality ◽  
Melt Pool ◽  
Wide Range ◽  
Am Processes

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM processes principles. Selective Laser Melting (SLM) is a widespread Powder Bed Fusion (PBF) AM process that due to its superior advantages, such as capability to print complex and highly customized components, which leads to an increasing attention paid by industries and academia. Temperature distribution and melt pool dynamics have paramount importance to be well simulated and correlated by part quality in terms of surface finish, induced residual stress and microstructure evolution during SLM. Summarizing numerical simulations of SLM in this survey is pointed out as one important research perspective as well as exploring the contribution of adopted approaches and practices. This review survey has been organized to give an overview of AM processes such as extrusion, photopolymerization, material jetting, laminated object manufacturing, and powder bed fusion. And in particular is targeted to discuss the conducted numerical simulation of SLM to illustrate a uniform picture of existing nonproprietary approaches to predict the heat transfer, melt pool behavior, microstructure and residual stresses analysis.

Review on Powder-Bed Laser Additive Manufacturing of Inconel 718 Parts

2015 ◽  
Author(s):  
Xiaoqing Wang ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Literature Review ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Manufacturing Processes ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Powder Bed ◽  
General Aspects

This study presents a thorough literature review on the powder-bed laser additive manufacturing processes such as selective laser melting (SLM) of Inconel 718 parts. The paper first introduces the general aspects of powder-bed laser additive manufacturing and then discusses the unique characteristics and advantages of SLM. Moreover, the bulk of this study includes extensive discussions of microstructures and mechanical properties, together with the application ranges, of Inconel 718 parts fabricated by SLM.

Thermal Modeling in Metal Additive Manufacturing Using Graph Theory

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
M. Reza Yavari ◽  
Kevin D. Cole ◽  
Prahalada Rao
Keyword(s):  
Finite Element ◽  
Graph Theory ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Process Parameters ◽  
Green’S Functions ◽  
Theory Approach ◽  
Finite Element Analyses ◽  
Part Quality ◽  
Am Processes

The goal of this work is to predict the effect of part geometry and process parameters on the instantaneous spatiotemporal distribution of temperature, also called the thermal field or temperature history, in metal parts as they are being built layer-by-layer using additive manufacturing (AM) processes. In pursuit of this goal, the objective of this work is to develop and verify a graph theory-based approach for predicting the temperature distribution in metal AM parts. This objective is consequential to overcome the current poor process consistency and part quality in AM. One of the main reasons for poor part quality in metal AM processes is ascribed to the nature of temperature distribution in the part. For instance, steep thermal gradients created in the part during printing leads to defects, such as warping and thermal stress-induced cracking. Existing nonproprietary approaches to predict the temperature distribution in AM parts predominantly use mesh-based finite element analyses that are computationally tortuous—the simulation of a few layers typically requires several hours, if not days. Hence, to alleviate these challenges in metal AM processes, there is a need for efficient computational models to predict the temperature distribution, and thereby guide part design and selection of process parameters instead of expensive empirical testing. Compared with finite element analyses techniques, the proposed mesh-free graph theory-based approach facilitates prediction of the temperature distribution within a few minutes on a desktop computer. To explore these assertions, we conducted the following two studies: (1) comparing the heat diffusion trends predicted using the graph theory approach with finite element analysis, and analytical heat transfer calculations based on Green’s functions for an elementary cuboid geometry which is subjected to an impulse heat input in a certain part of its volume and (2) simulating the laser powder bed fusion metal AM of three-part geometries with (a) Goldak’s moving heat source finite element method, (b) the proposed graph theory approach, and (c) further comparing the thermal trends predicted from the last two approaches with a commercial solution. From the first study, we report that the thermal trends approximated by the graph theory approach are found to be accurate within 5% of the Green’s functions-based analytical solution (in terms of the symmetric mean absolute percentage error). Results from the second study show that the thermal trends predicted for the AM parts using graph theory approach agree with finite element analyses, and the computational time for predicting the temperature distribution was significantly reduced with graph theory. For instance, for one of the AM part geometries studied, the temperature trends were predicted in less than 18 min within 10% error using the graph theory approach compared with over 180 min with finite element analyses. Although this paper is restricted to theoretical development and verification of the graph theory approach, our forthcoming research will focus on experimental validation through in-process thermal measurements.

Simulation of metallic powder bed additive manufacturing processes with the finite element method: A critical review

2016 ◽  
Vol 231 (1) ◽  
pp. 96-117 ◽  
Author(s):  
Babis Schoinochoritis ◽  
Dimitrios Chantzis ◽  
Konstantinos Salonitis
Keyword(s):  
Finite Element ◽  
Additive Manufacturing ◽  
Experimental Validation ◽  
Metallic Powder ◽  
Manufacturing Processes ◽  
Powder Bed ◽  
Modeling Methodology ◽  
Melt Pool ◽  
Element Simulation ◽  
Melt Pool Characteristics

This article provides a literature review of finite element simulation studies for metallic powder bed additive manufacturing processes. The various approaches in the numerical modeling of the processes and the selection of materials properties are presented in detail. Simulation results are categorized according to three major findings’ groups (i.e. temperature field, residual stresses and melt pool characteristics). Moreover, the means used for the experimental validation of the simulation findings are described. Looking deeper into the studies reviewed, a number of future directions are identified in the context of transforming simulation into a powerful tool for the industrial application of additive manufacturing. Smart modeling approaches should be developed, materials and their properties should be further characterized and standardized, commercial packages specialized in additive manufacturing simulation have to be developed and simulation needs to become part of the modern digital production chains. Finally, the reviewed studies are organized in a table and characterized according to the process and material studied, the modeling methodology and the experimental validation method used in each of them. The key findings of the reviewed studies are also summarized.

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