scholarly journals Analysis of Spatter Removal by Sieving during a Powder-Bed Fusion Manufacturing Campaign in Grade 23 Titanium Alloy

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 399
Author(s):  
Ryan Harkin ◽  
Hao Wu ◽  
Sagar Nikam ◽  
Justin Quinn ◽  
Shaun McFadden
Keyword(s):  
Computer Aided Design ◽  
Compositional Analysis ◽  
Mesh Size ◽  
Particle Morphology ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Powder Particles ◽  
Sieving Process

The Laser-based Powder Bed Fusion (L-PBF) process uses a laser beam to selectively melt powder particles deposited in a layer-wise fashion to manufacture components derived from Computer-Aided Design (CAD) information. During laser processing, material is ejected from the melt pool and is known as spatter. Spatter particles can have undesirable geometries for the L-PBF process, thereby compromising the quality of the powder for further reuse. An integral step in any powder replenishing and reuse procedure is the sieving process. The sieving process captures spatter particles within the exposed powder that have a diameter larger than a defined mesh size. This manuscript reports on Ti6Al4V (Grade 23) alloy powder that had been subjected to seven reuse iterations, focusing on the characterisation of powder particles that had been captured (i.e., removed) by the sieving processes. Characterisation included chemical composition focusing upon interstitial elements O, N and H (wt.%), particle morphology and particle size analysis. On review of the compositional analysis, the oxygen contents were 0.43 wt.% and 0.40 wt.% within the 63 µm and 50 µm sieve-captured powder, respectively. Additionally, it was found that a minimum of 79% and 63% of spatter particles were present within the captured powder removed by the 63 µm and 50 µm sieves, respectively.

scholarly journals Reuse of Grade 23 Ti6Al4V Powder during the Laser-Based Powder Bed Fusion Process

Metals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1700
Author(s):  
Ryan Harkin ◽  
Hao Wu ◽  
Sagar Nikam ◽  
Justin Quinn ◽  
Shaun McFadden
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Compositional Analysis ◽  
Powder Bed Fusion ◽  
Property Variation ◽  
Powder Bed ◽  
Melt Pool ◽  
Powder Particles ◽  
Powder Recycling

Titanium alloy powder used for laser-based powder bed fusion (L-PBF) process is costly. One of the solutions is the inclusion of a powder recycling strategy, allowing unused or exposed powder particles to be recuperated post manufacture, replenished and used for future builds. However, during a L-PBF process, powder particles are exposed to high levels of concentrated energy from the laser. Particularly those in close proximity to the melt pool, leading to the formation of spatter and agglomerated particles. These particles can settle onto the powder bed, which can then influence the particle size distribution and layer uniformity. This study analysed extra-low interstitial (ELI) Ti6Al4V (Grade 23) powder when subjected to nine recycle iterations, tracking powder property variation across the successive recycling stages. Characterisation included chemical composition focusing upon O, N, and H content, particle size distribution, morphology and tapped and bulk densities. On review of the compositional analysis, the oxygen content exceeded the 0.13% limit for the ELI grade after 8 recycles, resulting in the degradation from Grade 23 level.

Powder Bed Fusion of Biomedical Co-Cr-Mo and Ti-6Al-4V Alloys: Microstructure and Mechanical Properties

2019 ◽  
Vol 1151 ◽  
pp. 3-7 ◽  
Author(s):  
Eleonora Santecchia ◽  
Paolo Mengucci ◽  
Andrea Gatto ◽  
Elena Bassoli ◽  
Lucia Denti ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Tensile Tests ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
X Ray Diffraction ◽  
Powder Bed ◽  
Mechanical Parts ◽  
Aided Design ◽  
Microscopy Techniques ◽  
High Degree

Powder bed fusion (PBF) is an additive manufacturing technique, which allows to build complex functional mechanical parts layer-by-layer, starting from a computer-aided design (CAD) model. PBF is particularly attractive for biomedical applications, where a high degree of individualization is required. In this work, the microstructure of two biomedical alloys, namely Co-Cr-Mo and Ti-6Al-4V, were studied by X-ray diffraction and electron microscopy techniques. Hardness and tensile tests were performed on the sintered parts.

scholarly journals Preparation and Characterization of Betel Leaves (Piper betle Linn) Extract Nanoparticle with Ionic Gelation Method

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Dwi Saryanti ◽  
Dian Nugraheni ◽  
Nisa Sindi Astuti
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Leaf Extract ◽  
Particle Morphology ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Piper Betle ◽  
Ionic Gelation ◽  
Betel Leaf

Nanoparticles are used in drug delivery which can increase mass transfer so increase the absorption and effectiveness of the drug. Therefore, its prospect to improve antibacterial and antioxidants activities of betel leaves. The research aimed to preparation and characterization of betel leaf extract using ionic gelation technique. The formulation of nanoparticles from betel leaf extract with ionic gelation method using alginate and CaCl2 with a ratio of 2.5: 1. The characterization of the nanoparticles includes particle size analysis, zeta potential, particle morphology and determination of flavonoid content. Particle size analysis demonstrated that the betel leaf extract nanoparticles had a particle size of 243,03 ± 1,48 nm, zeta potential of -23,0 ± 0,35 mV and morphology of particle showed that a flat shape. The betle leaf exctract nanoparticle positively contained flavonoid with Rf 0.7 equivalent to quercetin. The betel leaf extract can be made nanoparticles with ionic gelation method using alginate and CaCl2.

Measured Data Alignments for Monitoring Metal Additive Manufacturing Processes Using Laser Powder Bed Fusion Methods

2020 ◽  
Author(s):  
Shaw C. Feng ◽  
Yan Lu ◽  
Albert T. Jones
Keyword(s):  
Coordinate System ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Ex Situ ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Alignment Procedure ◽  
3D Cad ◽  
Data Alignment ◽  
Cad Models

Abstract The number and types of measurement devices used for monitoring and controlling Laser-Based Powder Bed Fusion of Metals (PBF-LB/M) processes and inspecting the resulting AM metal parts have increased rapidly in recent years. The variety of the data collected by such devices has increased, and the veracity of the data has decreased simultaneously. Each measurement device generates data in a unique coordinate system and in a unique data type. Data alignment, however, is required before 1) monitoring and controlling PBF-LB/M processes, 2) predicting the material properties of the final part, and 3) qualifying the resulting AM parts can be done. Aligned means all data must be transformed into a single coordinate system. In this paper, we describe a new, general data-alignment procedure and an example based on PBF-LB/M processes. The specific data objects used in this example include in-situ photogrammetry, thermography, ex-situ X-ray computed tomography (XCT), coordinate metrology, and computer-aided design (CAD) models. We propose a data-alignment procedure to align the data from melt pool images, scan paths, layer images, XCT three-dimensional (3D) model, coordinate measurements, and the 3D CAD model.

A Combined Experimental-Numerical Method to Evaluate Powder Thermal Properties in Laser Powder Bed Fusion

2018 ◽  
Author(s):  
Bo Cheng ◽  
Brandon Lane ◽  
Justin Whiting ◽  
Kevin Chou
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Laser Flash ◽  
Powder Layer ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Powder Particles

Powder bed metal additive manufacturing (AM) utilizes a high-energy heat source scanning at the surface of a powder layer in a pre-defined area to be melted and solidified to fabricate parts layer by layer. It is known that powder bed metal AM is primarily a thermal process and further, heat conduction is the dominant heat transfer mode in the process. Hence, understanding the powder bed thermal conductivity is crucial to process temperature predictions, because powder thermal conductivity could be substantially different from its solid counterpart. On the other hand, measuring the powder thermal conductivity is a challenging task. The objective of this study is to investigate the powder thermal conductivity using a method that combines a thermal diffusivity measurement technique and a numerical heat transfer model. In the experimental aspect, disk-shaped samples, with powder inside, made by a laser powder bed fusion (LPBF) system, are measured using a laser flash system to obtain the thermal diffusivity and the normalized temperature history during testing. In parallel, a finite element model is developed to simulate the transient heat transfer of the laser flash process. The numerical model was first validated using reference material testing. Then, the model is extended to incorporate powder enclosed in an LPBF sample with thermal properties to be determined using an inverse method to approximate the simulation results to the thermal data from the experiments. In order to include the powder particles’ contribution in the measurement, an improved model geometry, which improves the contact condition between powder particles and the sample solid shell, has been tested. A multi-point optimization inverse heat transfer method is used to calculate the powder thermal conductivity. From this study, the thermal conductivity of a nickel alloy 625 powder in powder bed conditions is estimated to be 1.01 W/m·K at 500 °C.

Powder-Scale Meshfree Simulations of Powder Bed Fusion Based Additive Manufacturing Processes

2019 ◽  
Author(s):  
Zongyue Fan ◽  
Hao Wang ◽  
Bo Li
Keyword(s):  
Additive Manufacturing ◽  
Optimal Transportation ◽  
The Novel ◽  
Powder Bed Fusion ◽  
Computational Framework ◽  
Powder Bed ◽  
Materials Behaviors ◽  
Melt Pool ◽  
Powder Particles ◽  
Am Processes

Abstract We present a powder-scale meshfree direct numerical simulation (DNS) capability for the powder bed fusion (PBF) based additive manufacturing (AM) processes using the novel Hot Optimal Transportation Meshfree (HOTM) method. The HOTM method is an incremental Lagrangian meshfree computational framework for materials behaviors under extreme thermomechanical loading conditions, which combines the Optimal Transportation Meshfree (OTM) method and the variational thermomechanical constitutive updates. The realistic multi-layer powder bed geometry is modeled explicitly in the HOTM simulations based on experimental data. A phase-aware constitutive model is developed to predict the phase change and multiphase mixing during the PBF AM processes automatically. The governing equations including the linear momentum and energy conservation equations are solved for the multiphase flow simultaneously to predict the deformation, temperature and local state of the powder particles. The powder-scale DNS is employed to study the influence of various laser powers on the melt pool thermodynamics.

scholarly journals Particle Size Imbalance Index from Compositional Analysis to Evaluate Cereal Sustainability for Arid Soils in Eastern Algeria

Agriculture ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 296
Author(s):  
Siham Zaaboubi ◽  
Lotfi Khiari ◽  
Salah Abdesselam ◽  
Jacques Gallichand ◽  
Fassil Kebede ◽  
...  
Keyword(s):  
Particle Size ◽  
Management Practices ◽  
Compositional Analysis ◽  
Fine Sand ◽  
Particle Size Analysis ◽  
Coarse Sand ◽  
Richards Equation ◽  
Size Analysis ◽  
Fine Silt ◽  
Eastern Algeria

For homogeneous fertilization and crop management practices, this work hypothesized that texture could influence cereal yield, particularly in dry regions. Particle size analysis could help improve knowledge of the soil-plant relationship to obtain favorable conditions for better yield. The objective of this work is to develop a single granulometric index for durum wheat (Triticum durum) that is well correlated with yield. For this purpose, 350 independent samples of cereal soils from eastern Algeria were taken and the recorded yields were linked to these samples. The cutoff yield, which separates sub-populations with acceptable yield from those with less acceptable yield, was determined from the inflection point of the cumulative variance ratio functions related to yield by the Richards’ equation. The result obtained is 2.0 Mg.ha−1, with a theoretical critical chi-square value of 4.2, close to 4.6, which is the critical value of r2granulo as obtained by the Cate-Nelson procedure. The five-granulometric indices were found to be symmetrical around zero as follows: ±0.83 for clay (IC), ±1.73 for fine silt (IFL), ±0.31 for coarse silt (ICL), ±0.44 for fine sand (IFS), and ±1.30 for coarse sand (ICS). The two fractions that most influence the textural imbalance are fine silt (IFL) and coarse sand (ICS), with a contribution of 41% and 37%, respectively. The critical single imbalance index r g r a n u l o 2 can be used for determining cereal suitability for soils in the arid region of eastern Algeria. The lower the   r g r a n u l o 2 is, the better the soil for cereal crops.

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