Predictive simulation of process windows for powder bed fusion additive manufacturing: Influence of the powder size distribution

Metal powders suitable for use in powder bed additive manufacturing processes should ideally be spherical, dense, chemically pure and of a specified particle size distribution. Ti6Al4V is commonly used in the aerospace, medical and automotive industries due to its high strength-to-weight ratio and excellent corrosion resistance properties. Interstitial impurities in titanium alloys have an impact upon mechanical properties, particularly oxygen, nitrogen, hydrogen and carbon. The plasma spheroidisation process can be used to spheroidise metal powder consisting of irregularly shaped particles. In this study, the plasma spheroidisation of metal powder was performed on Ti6Al4V powder consisting of irregularly shaped particles. The properties of the powder relevant for powder bed fusion that were determined included the particle size distribution, morphology, particle porosity and chemical composition. Conclusions were drawn regarding the viability of using this process to produce powder suitable for additive manufacturing.

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Application of Electrostatic Adhesion Method in Metal-Powder-Based Additive Manufacturing Layer-Forming Process

Volume 2: Advanced Manufacturing ◽

10.1115/imece2018-88741 ◽

2018 ◽

Author(s):

Teng-Yueh Tsao ◽

Jen-Yuan (James) Chang

Keyword(s):

Additive Manufacturing ◽

Size Distribution ◽

Layer Thickness ◽

Dielectric Layer ◽

Powder Layer ◽

Powder Size ◽

Electrostatic Model ◽

Electrostatic Deposition ◽

Powder Size Distribution ◽

Electrostatic Adhesion

Similar to direct energy deposition (DED) technology, electrostatic adhesion method can also be employed to deposit powder on targeted areas without direct contact. In this paper, feasibility of utilizing the electrostatic adhesion method (EAM) in material deposition step of metal-power-based additive manufacturing is assessed through theoretical models and experimental verifications. A dielectric layer is proposed to be pre-coated on targeted areas to keep the powders being electrostatically attracted and charged without dropping before laser scanning process. Through this study, it is found that the net force of a single metallic particle on top of the deposited powder layer with a different thickness of the dielectric layer can be determined, leading to the suggestion of suitable coating thickness corresponding with desired particle radius. Results showed that the deposition layer thickness can be predicted with the knowing coated dielectric layer thickness and the powder size distribution. With the proposed electrostatic deposition method, a thinner layer compared to DED technology can be deposited, while maintaining its ability to deposit powder layer over a larger area. Through experiments, the developed electrostatic model is validated with results indicating that the deposition layer thickness can be predicted and controlled with the knowing coated dielectric layer thickness and the powder size distribution.

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Predictive Simulation of Process Windows for Powder Bed Fusion Additive Manufacturing: Influence of the Powder Bulk Density

Materials ◽

10.3390/ma10101117 ◽

2017 ◽

Vol 10 (10) ◽

pp. 1117 ◽

Cited By ~ 29

Author(s):

Alexander Rausch ◽

Vera Küng ◽

Christoph Pobel ◽

Matthias Markl ◽

Carolin Körner

Keyword(s):

Additive Manufacturing ◽

Bulk Density ◽

Powder Bed Fusion ◽

Powder Bed ◽

Predictive Simulation

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Physics‐based modeling and predictive simulation of powder bed fusion additive manufacturing across length scales

GAMM-Mitteilungen ◽

10.1002/gamm.202100014 ◽

2021 ◽

Author(s):

Christoph Meier ◽

Sebastian L. Fuchs ◽

Nils Much ◽

Jonas Nitzler ◽

Ryan W. Penny ◽

...

Keyword(s):

Additive Manufacturing ◽

Powder Bed Fusion ◽

Length Scales ◽

Powder Bed ◽

Predictive Simulation

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Powder Reuse Cycles in Electron Beam Powder Bed Fusion—Variation of Powder Characteristics

Materials ◽

10.3390/ma14164602 ◽

2021 ◽

Vol 14 (16) ◽

pp. 4602

Author(s):

Gitanjali Shanbhag ◽

Mihaela Vlasea

Keyword(s):

Electron Beam ◽

Nitrogen Content ◽

Size Distribution ◽

Angle Of Repose ◽

Powder Size ◽

Powder Bed Fusion ◽

Powder Bed ◽

Flow Energy ◽

Hausner Ratio ◽

Powder Characteristics

A path to lowering the economic barrier associated with the high cost of metal additively manufactured components is to reduce the waste via powder reuse (powder cycled back into the process) and recycling (powder chemically, physically, or thermally processed to recover the original properties) strategies. In electron beam powder bed fusion, there is a possibility of reusing 95–98% of the powder that is not melted. However, there is a lack of systematic studies focusing on quantifying the variation of powder properties induced by number of reuse cycles. This work compares the influence of multiple reuse cycles, as well as powder blends created from reused powder, on various powder characteristics such as the morphology, size distribution, flow properties, packing properties, and chemical composition (oxygen and nitrogen content). It was found that there is an increase in measured response in powder size distribution, tapped density, Hausner ratio, Carr index, basic flow energy, specific energy, dynamic angle of repose, oxygen, and nitrogen content, while the bulk density remained largely unchanged.

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Effect of powder size and processing parameters on surface, density and mechanical properties of 316L elaborated by Laser Powder Bed Fusion

10.25518/esaform21.1563 ◽

2021 ◽

Author(s):

Sabrine Ziri ◽

Anis Hor ◽

Catherine Mabru

Keyword(s):

Mechanical Properties ◽

Surface Roughness ◽

Size Distribution ◽

Research Work ◽

Processing Parameters ◽

Powder Size ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Stainless Steel 316L ◽

Powder Bed

Despite the attractive capabilities of additive manufacturing (AM) technology, the industrialization of these processes remains very low. This is attributed to the complexes physical phenomena involved in the AM process and the layered structure of the produced parts. Intense research work is still needed for the prediction and optimization of AM parts mechanical properties. In this study, the influence of particle size distribution (PSD) of stainless steel 316L (SS 316L) powders on AM parts properties was investigated. Four PSD were used to produce test parts and compare the resulting porosity, surface roughness and macro-hardness. The SS 316L specimens were fabricated by Laser Powder Bed Fusion process (LPBF) on a SLM 125HL machine using variations in laser power and scan velocity. Computed scan tomography (CT) was used to characterize the defects. Lack of fusion and keyhole defects were detected. Defects were detected even in nearly dense parts. The powder size distribution was found to affect the porosity. Results from CT tests were used to identify the minimum achievable porosities for each powder, through the appropriate selection of process parameters. The macro-hardness and surface roughness were found to vary with the powder properties.

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