Multi-Objective Build Orientation Optimization for Powder Bed Fusion by Laser

2017 ◽  
Author(s):  
Salah Eddine Brika ◽  
Justin Mezzetta ◽  
Mathieu Brochu ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Integrated Approach ◽  
Powder Bed Fusion ◽  
Support Structure ◽  
Powder Bed ◽  
Build Orientation ◽  
Multi Objective ◽  
Build Time ◽  
Process Factors

This paper proposes an integrated approach to determine optimal build orientation for Powder bed fusion by laser (PBF-L), by simultaneously optimizing mechanical properties, surface roughness, the amount of support structure and build time-cost. Experimental data analysis has been used to establish the objective functions for different mechanical properties and surface roughness. Geometry analysis of the part has been used to estimate the needed support structure and thus evaluate the build time and cost. Normalized weights are assigned to different objectives depending on their relative importance allowing solving the multi-objective optimization problem using a genetic optimization algorithm. A study case is presented to demonstrate the capabilities of the developed system. The major achievements of this work are the consideration of multiple objectives, the establishment of objective function considering different load direction and heat treatments. A user-friendly graphical user interface was developed allowing to control different optimization process factors and providing different visualization and evaluation tools.

Multi-Objective Build Orientation Optimization for Powder Bed Fusion by Laser

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Salah Eddine Brika ◽  
Yaoyao Fiona Zhao ◽  
Mathieu Brochu ◽  
Justin Mezzetta
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Integrated Approach ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Build Orientation ◽  
Multi Objective ◽  
Build Time ◽  
Process Factors ◽  
Experimental Data Analysis

This paper proposes an integrated approach to determine optimal build orientation for powder bed fusion by laser (PBF-L), by simultaneously optimizing mechanical properties, surface roughness, the amount of support structure (SUPP), and build time and cost. Experimental data analysis has been used to establish the objective functions for different mechanical properties and surface roughness. Geometry analysis of the part has been used to estimate the needed SUPP and thus evaluate the build time and cost. Normalized weights are assigned to different objectives depending on their relative importance allowing solving the multi-objective optimization problem using a genetic optimization algorithm. A study case is presented to demonstrate the capabilities of the developed system. The major achievements of this work are the consideration of multiple objectives and the establishment of objective function considering different load direction and heat treatments. A user-friendly graphical user interface was developed allowing to control different optimization process factors and providing different visualization and evaluation tools.

scholarly journals Influences of Process Parameters on the Microstructure and Mechanical Properties of CoCrFeNiTi Based High-Entropy Alloy in a Laser Powder Bed Fusion Process

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 549
Author(s):  
Takafumi Ikeda ◽  
Makiko Yonehara ◽  
Toshi-Taka Ikeshoji ◽  
Tohru Nobuki ◽  
Minoru Hatate ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Process Parameters ◽  
Laser Power ◽  
Powder Bed Fusion ◽  
Process Map ◽  
Powder Bed ◽  
High Entropy ◽  
Scan Speed ◽  
Fabrication Condition

Recently, high-entropy alloys (HEAs) have attracted much attention because of their superior properties, such as high strength and corrosion resistance. This study aimed to investigate the influences of process parameters on the microstructure and mechanical properties of CoCrFe NiTiMo HEAs using a laser-based powder bed fusion (LPBF) process. In terms of laser power and scan speed, a process map was constructed by evaluating the density and surface roughness of the as-built specimen to optimize the process parameters of the products. The mechanical properties of the as-built specimens fabricated at the optimum fabrication condition derived from the process map were evaluated. Consequently, the optimum laser power and scan speed could be obtained using the process map evaluated by density and surface roughness. The as-built specimen fabricated at the optimum fabrication condition presented a relative density of more than 99.8%. The microstructure of the as-built specimen exhibited anisotropy along the build direction. The tensile strength and elongation of the as-built specimen were around 1150 MPa and more than 20%, respectively.

Effects of Build Orientation on Mechanical Properties of Curved-Surface AlSi10Mg Alloy Fabricated by Powder Bed Fusion Additive Manufacturing

2020 ◽  
Author(s):  
Yue Zhou ◽  
Fuda Ning
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Lattice Structure ◽  
Curved Surface ◽  
Thin Wall ◽  
Variable Cross ◽  
Curved Surfaces ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Build Orientation

Abstract AlSi10Mg alloy has been widely used in the aerospace and automotive industries due to its superior physical and mechanical properties. Most AlSi10Mg components possess complicated-geometrical characteristics, such as planar thin wall, lattice structure, curved surface, etc. In recent years, laser-based powder bed fusion (PBF) has emerged as a promising additive manufacturing technique to produce complex AlSi10Mg alloy parts with a high resolution. PBF of curved-surface components exhibit varied heat transfer conditions, challenging post-fabrication processes, and intricate force conditions during mechanical testing owing to their structural inflections and variable cross-sections. Thus, the mechanical properties of the as-built AlSi10Mg parts with curved surfaces should be comprehensively understood to facilitate the adoption of PBF-built curved-surface AlSi10Mg parts in practical engineering applications. This paper systematically investigated the effects of build orientation on the tensile property and microhardness of the PBF-built AlSi10Mg parts with curved surfaces. The results showed that both bending stress and stretching stress contributed to the overall tensile stress of the curved-surface tensile specimens, and the failure always occurred at the peak/valley locations of the sine curved surface due to the largest bending moment. Meanwhile, the ultimate tensile strength increased with the build orientation varying from 60° to 90°. In addition, the curvatures C2 and C4 presented the lowest microhardness while C1 and C5 showed the highest one.

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

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.

scholarly journals Surface Roughness Characterisation and Analysis of the Electron Beam Melting (EBM) Process

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2211 ◽  
Author(s):  
Manuela Galati ◽  
Paolo Minetola ◽  
Giovanni Rizza
Keyword(s):  
Surface Roughness ◽  
Electron Beam ◽  
Cross Section ◽  
Mass Production ◽  
Electron Beam Melting ◽  
Heat Distribution ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Key Factor ◽  
Process Factors

Electron Beam Melting (EBM) is a metal powder bed fusion (PBF) process in which the heat source is an electron beam. Differently from other metal PBF processes, today, EBM is used for mass production. As-built EBM parts are clearly recognisable by their surface roughness, which is, in some cases, one of the major limitations of the EBM process. The aim of this work is to investigate the effects of the orientation and the slope of the EBM surfaces on the surface roughness. Additionally, the machine repeatability is studied by measuring the roughness of surfaces built at different positions on the start plate. To these aims, a specific artefact was designed. Replicas of the artefact were produced using an Arcam A2X machine and Ti6Al4V powder. Descriptive and inferential statistical methods were applied to investigate whether the surface morphology was affected by process factors. The results show significant differences between the upward and downward surfaces. The upward surfaces appear less rough than the downward ones, for which a lower standard deviation was obtained in the results. The roughness of the upward surfaces is linearly influenced by the sloping angle, while the heat distribution on the cross-section was found to be a key factor in explaining the roughness of the downward surfaces.

scholarly journals On the Relevance of Volumetric Energy Density in the Investigation of Inconel 718 Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538 ◽  
Author(s):  
Fabrizia Caiazzo ◽  
Vittorio Alfieri ◽  
Giuseppe Casalino
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Process Parameters ◽  
Vickers Hardness ◽  
Powder Bed Fusion ◽  
Processing Conditions ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Fractional Density ◽  
Experimental Variation

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.

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