Advances in Nanoparticle Sintering Simulation: Multiple Layer Sintering and Sintering Subject to a Heat Gradient

2021 ◽  
Author(s):  
Obehi Dibua ◽  
Chee S. Foong ◽  
Michael Cullinan
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Sintering Behavior ◽  
Manufacturing Processes ◽  
Isothermal Heating ◽  
Temperature Changes ◽  
Powder Bed ◽  
Field Modelling ◽  
Current State ◽  
Temperature Heating

Abstract Nanoparticles are being used in Additive Manufacturing to improve on the minimum feature sizes that the processes are able to achieve. In order to accurately control this process, it is important to understand the underlying characteristics that define the sintering of nanoparticles. This is done by modelling the process. A nanoparticle simulation has been introduced to model the sintering between the nanoparticles in a powder bed. These simulations make use of Phase Field Modelling to track the diffusion between the particles in the system. However, the current state of the simulations only consider the sintering of single layers of powder beds subject to isothermal heating. For the simulation to be able to simulate an actual Additive Manufacturing process where a 3D part is built, the model has to consider the characteristics of multiple layers of nanoparticles in beds undergoing sintering. Additionally, during Additive Manufacturing processes like Selective Laser Sintering, where the bed is not undergoing an even temperature heating, a nanoparticle sintering simulation for this process must be able to account for these temperature changes. This paper presents advancements in simulating nanoparticle sintering to be able to model the sintering behavior between multiple layers of nanoparticles as well as the effects of a temperature gradient on the sintering of nanoparticles.

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 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.

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.

Additive Manufacturing Processes for Infrastructure Construction: A Review

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Abhinav Bhardwaj ◽  
Scott Z. Jones ◽  
Negar Kalantar ◽  
Zhijian Pei ◽  
John Vickers ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Construction Industry ◽  
Manufacturing Sector ◽  
Manufacturing Processes ◽  
Current State ◽  
Industry Applications ◽  
Am Processes

Additive manufacturing (AM) has had an enormous impact on the manufacturing sector. Its role has evolved from printing prototypes to manufacturing functional parts for a variety of applications in the automotive, aerospace, and medical industries. Recently, AM processes have also been applied in the infrastructure construction industry. Applications of AM processes could bring in significant improvements in infrastructure construction, specifically in the areas of productivity and safety. It is desirable to have a review on the current state of emerging AM processes for infrastructure construction and existing gaps in this field. This paper reviews the AM processes in infrastructure construction. It discusses the process principle, application examples, and gaps for each of the AM processes.

scholarly journals Review of Tailoring Methods for Joints with Additively Manufactured Adherends and Adhesives

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3949
Author(s):  
Mattia Frascio ◽  
Eduardo André de Sousa Marques ◽  
Ricardo João Camilo Carbas ◽  
Lucas Filipe Martins da Silva ◽  
Margherita Monti ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Review Paper ◽  
State Of The Art ◽  
Manufacturing Processes ◽  
Bonded Joints ◽  
Design For Additive Manufacturing ◽  
Polymeric Additive ◽  
Current State ◽  
Bonded Joint ◽  
Current Modelling

This review aims to assess the current modelling and experimental achievements in the design for additive manufacturing of bonded joints, providing a summary of the current state of the art. To limit its scope, the document is focused only on polymeric additive manufacturing processes. As a result, this review paper contains a structured collection of the tailoring methods adopted for additively manufactured adherends and adhesives with the aim of maximizing bonded joint performance. The intent is, setting the state of the art, to produce an overview useful to identify the new opportunities provided by recent progresses in the design for additive manufacturing, additive manufacturing processes and materials’ developments.

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.

Design and Modeling of a Microscale Selective Laser Sintering System

2016 ◽  
Author(s):  
Nilabh Roy ◽  
Anil Yuksel ◽  
Michael Cullinan
Keyword(s):  
Heat Transfer ◽  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Feature Size ◽  
Powder Bed ◽  
Metal Additive Manufacturing ◽  
Wave Nature ◽  
Field Radiation ◽  
Metal Additive

The development of micro and nanoscale additive manufacturing methods in metals and ceramics is important for many applications in the aerospace, medical device, and electronics industries. Unfortunately, most commercially available metal additive manufacturing tools have feature-size resolutions of greater than 100 μm, which is too large to precisely control the microstructure of the parts they produce. A few research-grade metal additive manufacturing tools do exist, but their build rate is generally too slow for commercial applications. Therefore, this paper presents a new microscale selective laser sintering (μ-SLS) that can be used to improve the minimum feature-size resolution of metal additively manufactured parts by up to two orders of magnitude, while still maintaining the throughput of traditional additive manufacturing processes. In order to achieve this goal, several innovative design features like the use of (1) ultra-fast lasers, (2) a micro-mirror based optical system, (3) nanoscale powders, and (4) a precision spreader mechanism, have been implemented. The micro-SLS system is capable of achieving build rates of approximately 1 cm3/hr while achieving a feature-size resolution of approximately 1 μm. This paper will also present new molecular scale models that have been developed for the micro-SLS to quantify and certify the micro-SLS build process. Modeling of the micro-SLS process is challenging, because most macroscale models of the SLS process contain assumptions that are no longer valid when the size of the particles that are being sintered is smaller than the wavelength of the laser being used to sinter them. Therefore, in modeling the micro-SLS process we must account for the wave nature of light and can no longer rely on the ray tracing models commonly used to model the SLS process. Also, heat transfer in the micro-SLS process is dominated by near-field radiation due to the diffraction of the light off the nanoparticles in the powder bed and the ultrafast lasers that are used in the micro-SLS system. This means that the assumptions of heat transfer by conduction and far-field radiation in the macroscale SLS systems are no longer valid for the micro-SLS system. Finally, the agglomeration of nanoparticles in the powder bed must be accurately modeled in order to precisely predict the formation of defects in the final parts produced. Overall, the goal of this modeling effort is to be able to predict the quality of a part produced using any given processing conditions, in order to produce parts that are “born certified” and do not need to be tested post fabrication.

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