HEAT TRANSFER, PHASE CHANGE, AND COALESCENCE OF PARTICLES DURING SELECTIVE LASER SINTERING OF METAL POWDERS

2012 ◽  
Vol 4 (5) ◽  
pp. 411-423
Author(s):  
Ram Dayal ◽  
Tatiana Gambaryan-Roisman ◽  
Eberhard Abele
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Transfer Phase ◽  
Metal Powders

Evolution of Direct Selective Laser Sintering of Metals

2011 ◽  
Vol 383-390 ◽  
pp. 6252-6257
Author(s):  
Francesco Cardaropoli ◽  
Fabrizia Caiazzo ◽  
Vincenzo Sergi
Keyword(s):  
Complex Geometry ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Layer By Layer ◽  
Metal Powders ◽  
Additive Process ◽  
Operator Experience ◽  
Critical Phases ◽  
Time Required

Direct Metal Selective Laser Sintering (DMSLS) is a layer-by-layer additive process for metal powders, which allows quick production of complex geometry parts. The aim of this study is to analyse the improvement of DMSLS with “EOSINT M270”, the new laser sintering machine developed by EOS. Tests were made on sintered parts of Direct Metal 20 (DM20), a bronze based powder with a mean grain dimension of 20 μm. Different properties and accuracy were evaluated for samples manufactured with three different exposure strategies. Besides mechanical properties, the manufacturing process was also examined in order to evaluate its characteristics. The quality of laser sintered parts is too affected by operator experience and skill. Furthermore, critical phases are not automatic and this causes an extension of time required for the production. Due to these limitations, DMSLS can be used for Rapid Manufacturing, but it is especially suitable to few sample series.

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.

Selective laser sintering and cladding of single‐component metal powders

2004 ◽  
Vol 10 (2) ◽  
pp. 88-97 ◽  
Author(s):  
Nikolay K. Tolochko ◽  
Sergei E. Mozzharov ◽  
Igor A. Yadroitsev ◽  
Tahar Laoui ◽  
Ludo Froyen ◽  
...  
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Single Component ◽  
Metal Powders

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.

scholarly journals Mechanisms of selective laser sintering and heat transfer in Ti powder

2003 ◽  
Vol 9 (5) ◽  
pp. 314-326 ◽  
Author(s):  
Nikolay K. Tolochko ◽  
Maxim K. Arshinov ◽  
Andrey V. Gusarov ◽  
Victor I. Titov ◽  
Tahar Laoui ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Ti Powder
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