Single Track Formation during Selective Laser Melting of Ti-6Al-4V Alloy

Selective laser melting (SLM) is an additive manufacturing technology that allows to produce functional parts with extremely complex shape from metal powder feedstock. 240 single tracks with the length of 10 mm were fabricated using different SLM process parameters: laser power output, powder layer thickness, point distance and exposure time. Obtained single tracks were measured using optical microscopy. An influence of SLM process parameters on geometrical characteristics of obtained single tracks was investigated.

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Effect of Process Parameters and Layer Thickness on the Quality and Performance of Ti-6Al-4V Fabricated by Selective Laser Melting

Coatings ◽

10.3390/coatings11111323 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1323

Author(s):

Yanlong Jing ◽

Peng Wang ◽

Xiaoling Yan

Keyword(s):

Surface Quality ◽

Selective Laser Melting ◽

Exposure Time ◽

Process Parameters ◽

Laser Power ◽

Single Track ◽

Laser Melting ◽

Powder Bed ◽

Point Distance

To improve the quality of thick powder bed and realize the matching of thick powder bed and thin powder bed in the later stage, the influence of process parameters for the single-track, multi-layer fabrication, relative density, surface quality, defect, remelting, and boundary optimization performance of different layer thicknesses of Ti-6Al-4V fabricated by selective laser melting were investigated. It is more conducive to the stable forming of single-track when the point distance is half the diameter of the laser beam, and the exposure time is appropriately extended. The thin powder bed needs the corresponding point distance and exposure time under the laser power of 280–380 W to obtain high-density specimens. The thick powder bed needs to be able to ensure the formation of high-quality specimens under the smaller point distance and longer exposure time under higher laser power of 380 W. Both thick powder bed and thin powder bed will cause un-melted defects between molten pools, spheroidization defects caused by splashing, and microporous defects. The remelting process can significantly improve the surface quality of the formed specimen, but the surface quality of the thick powder bed is worse than that of the thin powder bed. The boundary quality of thick powder bed is worse than that of thin powder bed, and the boundary shape has a greater influence on the quality of the SLM forming boundary. Different strategies should be adopted to form the boundary of different shapes. Increasing the boundary count and increasing the laser power are more conducive to the improvement of boundary quality.

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Thermo-Fluid Modeling of Selective Laser Melting: Single-Track Formation Incorporating Metallic Powder

Journal of Materials Engineering and Performance ◽

10.1007/s11665-018-3574-5 ◽

2018 ◽

Vol 28 (2) ◽

pp. 611-619 ◽

Cited By ~ 7

Author(s):

Subin Shrestha ◽

Santosh Rauniyar ◽

Kevin Chou

Keyword(s):

Selective Laser Melting ◽

Metallic Powder ◽

Single Track ◽

Laser Melting ◽

Fluid Modeling ◽

Track Formation

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Numerical Simulation of Moving Heat Flux during Selective Laser Melting of AlSi25 Alloy Powder

Metals ◽

10.3390/met10070877 ◽

2020 ◽

Vol 10 (7) ◽

pp. 877

Author(s):

Cong Ma ◽

Xianshun Wei ◽

Biao Yan ◽

Pengfei Yan

Keyword(s):

Numerical Simulation ◽

Selective Laser Melting ◽

Process Parameters ◽

Molten Pool ◽

Laser Power ◽

Scanning Speed ◽

Powder Layer ◽

Maximum Temperature ◽

Three Dimensional Model ◽

Laser Melting

A single-layer three-dimensional model was created to simulate multi-channel scanning of AlSi25 powder in selective laser melting (SLM) by the finite element method. Thermal behaviors of laser power and scanning speed in the procedure of SLM AlSi25 powder were studied. With the increase of laser power, the maximum temperature, size and cooling rate of the molten pool increase, while the scanning speed decreases. For an expected SLM process, a perfect molten pool can be generated using process parameters of laser power of 180 W and a scanning speed of 200 mm/s. The pool is greater than the width of the scanning interval, the depth of the molten pool is close to scan powder layer thickness, the temperature of the molten pool is higher than the melting point temperature of the powder and the parameters of the width and depth are the highest. To confirm the accuracy of the simulation results of forecasting excellent process parameters, the SLM experiment of forming AlSi25 powder was carried out. The surface morphology of the printed sample is intact without holes and defects, and a satisfactory metallurgical bond between adjacent scanning channels and adjacent scanning layers was achieved. Therefore, the development of numerical simulation in this paper provides an effective method to obtain the best process parameters, which can be used as a choice to further improve SLM process parameters. In the future, metallographic technology can also be implemented to obtain the width-to-depth ratio of the SLM sample molten pool, enhancing the connection between experiment and theory.

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Effects of the powder morphology, size distribution, and characteristics on the single track formation in selective laser melting of H13 steel

Journal of Advanced Mechanical Design Systems and Manufacturing ◽

10.1299/jamdsm.2021jamdsm0035 ◽

2021 ◽

Vol 15 (3) ◽

pp. JAMDSM0035-JAMDSM0035

Author(s):

Mitsugu YAMAGUCHI ◽

Tatsuaki FURUMOTO ◽

Yuuya TANABE ◽

Shinnosuke YAMADA ◽

Mototsugu OSAKI ◽

...

Keyword(s):

Size Distribution ◽

Selective Laser Melting ◽

Single Track ◽

Laser Melting ◽

H13 Steel ◽

Powder Morphology ◽

Track Formation

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Quasicrystalline Composites by Additive Manufacturing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.818.72 ◽

2019 ◽

Vol 818 ◽

pp. 72-76 ◽

Cited By ~ 3

Author(s):

Konda Gokuldoss Prashanth ◽

Sergio Scudino

Keyword(s):

Mechanical Properties ◽

Additive Manufacturing ◽

Selective Laser Melting ◽

Process Parameters ◽

Complex Shape ◽

Powder Bed Fusion ◽

Laser Melting ◽

Powder Bed ◽

Novel Materials ◽

Tunable Properties

Laser based powder bed fusion (LBPF) or selective laser melting (SLM) is making a leap march towards fabricating novel materials with improved functionalities. An attempt has been made here to fabricate hard quasicrystalline composites via SLM, which demonstrates that the process parameters can be used to vary the phases in the composites. The mechanical properties of the composite depend on their constituents and hence can be varied by varying the process parameters. The results show that SLM not only produces parts with improved functionalities and complex shape but also leads to defined phases and tunable properties.

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Selective Laser Melting of Pre-Alloyed NiTi Powder: Single-Track Study and FE Modeling with Heat Source Calibration

Materials ◽

10.3390/ma14237486 ◽

2021 ◽

Vol 14 (23) ◽

pp. 7486

Author(s):

Stanislav V. Chernyshikhin ◽

Denis G. Firsov ◽

Igor V. Shishkovsky

Keyword(s):

Heat Source ◽

Thermal Behavior ◽

Selective Laser Melting ◽

Process Parameters ◽

Laser Power ◽

Scanning Speed ◽

Fe Modeling ◽

Single Track ◽

Laser Melting ◽

Melt Pool

Unique functional properties such as the low stiffness, superelasticity, and biocompatibility of nickel–titanium shape-memory alloys provide many applications for such materials. Selective laser melting of NiTi enables low-cost customization of devices and the manufacturing of highly complex geometries without subsequent machining. However, the technology requires optimization of process parameters in order to guarantee high mass density and to avoid deterioration of functional properties. In this work, the melt pool geometry, surface morphology, formation mode, and thermal behavior were studied. Multiple combinations of laser power and scanning speed were used for single-track preparation from pre-alloyed NiTi powder on a nitinol substrate. The experimental results show the influence of laser power and scanning speed on the depth, width, and depth-to-width aspect ratio. Additionally, a transient 3D FE model was employed to predict thermal behavior in the melt pool for different regimes. In this paper, the coefficients for a volumetric double-ellipsoid heat source were calibrated with bound optimization by a quadratic approximation algorithm, the design of experiments technique, and experimentally obtained data. The results of the simulation reveal the necessary conditions of transition from conduction to keyhole mode welding. Finally, by combining experimental and FE modeling results, the optimal SLM process parameters were evaluated as P = 77 W, V = 400 mm/s, h = 70 μm, and t = 50 μm, without printing of 3D samples.

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DoE Applied to Thermal Analysis and Simulation of Geometrical Stability of a Wind Turbine Blade Made by Selective Laser Melting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1161.65 ◽

2021 ◽

Vol 1161 ◽

pp. 65-74

Author(s):

Abbas Razavykia ◽

Eugenio Brusa ◽

Sina Ghodsieh ◽

Lorenzo Giorio

Keyword(s):

Wind Turbine ◽

Selective Laser Melting ◽

Turbine Blade ◽

Process Parameters ◽

Thermal Stresses ◽

Wind Turbine Blade ◽

Powder Layer ◽

Laser Melting ◽

Influence Of Process Parameters ◽

Wide Range

The Selective Laser Melting (SLM) is one of the most demanding additive manufacturing(AM) processes, although it assures some superior advantages in producing complex structural componentsand applies to a wide range of materials. The control of SLM parameters is crucial to guaranteethe quality of manufactured component. The steep thermal variation in part during the SLM processinduces some undesired effects, such as warping, residual thermal stresses and microcracks,as wellas geometrical instability. Effectively predicting the influence of process parameters upon the productquality of part made by SLM is extremely useful in the earliest steps of design, especially whena higher productivity is required. Particularly, thermal simulation is used to suitably calibrate someprocess parameters, to improve efficiency and reduce defects. Besides, such simulation is exploited toimprove the heat transfer between the bed and the first product layer, to reduce thermal stress and theoverall product deformation. This study exemplifies how numerical modeling of temperature distributionin a wind turbine blade made by SLM allows predicting the dimensional stability. The Design ofExperiments (DoE) and ANOVA analysis helped in studying effects on the product geometric stabilityand deformation, of some process parameters, as powder layer thickness, hatch space and laser scanspeed.

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