Studying Gas-Phase Flows in the Laser Exposure Zone during Selective Laser Melting

2020 ◽  
Vol 989 ◽  
pp. 806-810
Author(s):  
Pavel Anatolyevich Podrabinnik ◽  
C.E. Protasov ◽  
A.V. Gusarov
Keyword(s):  
Selective Laser Melting ◽  
High Speed ◽  
Ccd Camera ◽  
Opening Angle ◽  
Laser Exposure ◽  
Laser Melting ◽  
Schlieren Method ◽  
Outflow Velocity ◽  
All Optical ◽  
Powder Particles

The processes occurring during selective laser melting were studied with a high-speed CCD camera. In order to record all optical in-homogeneities, the camera was integrated into optical arrangement, that realized the Schlieren-method. Within the experiment three parameters were estimated, such as powder particles opening angle, their velocity and the outflow velocity of vapor-gas jet. The influence of laser setup parameters is given. It is shown that particle size and material composition, together with laser power, affect greatly on the opening angle and velocity of powder particles emission, respectively.

scholarly journals Selective Laser Melting of Crack-Free High Density M2 High Speed Steel Parts by Baseplate Preheating

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Karolien Kempen ◽  
Bey Vrancken ◽  
Sam Buls ◽  
Lore Thijs ◽  
Jan Van Humbeeck ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
High Speed ◽  
Crack Formation ◽  
High Speed Steel ◽  
Thermal Gradients ◽  
Laser Melting ◽  
Mechanical And Physical Properties ◽  
The World ◽  
M2 High Speed Steel

Cracks and delamination, resulting from residual stresses, are a barrier in the world of additive manufacturing and selective laser melting (SLM) that prohibits the use of many metals in this field. By preheating the baseplate, thermal gradients are lowered and stresses can be reduced. In this work, some initial tests were performed with M2 high speed steel (HSS). The influence of preheating on density and mechanical and physical properties is investigated. The paper shows many promising results for the production of SLM parts in materials that are very sensitive to crack formation and delamination. When using a preheating of 200 °C, crack-free M2 HSS parts were produced with a relative density of 99.8%.

Influence of the Powder Particle Size on the Denudated Zone Width at Selective Laser Melting

2020 ◽  
Vol 989 ◽  
pp. 816-820
Author(s):  
Roman Sergeevich Khmyrov ◽  
R.R. Ableyeva ◽  
Tatiana Vasilievna Tarasova ◽  
A.V. Gusarov
Keyword(s):  
Particle Size ◽  
Selective Laser Melting ◽  
Powder Particle ◽  
Powder Particle Size ◽  
Adhesion Forces ◽  
Laser Melting ◽  
Friction Forces ◽  
Single Bead ◽  
Powder Particles

Mass transfer in the laser-interaction zone at selective laser melting influences the quality of the obtained material. Powder particles displacement during the formation of the single bead is experimentally studied. The so-called denudated zone was visualized by metallography. It was determined that increasing the powder particle size leads to widening the denudated zone. This can signify that the adhesion forces between powder particles prevail over the friction forces.

Selective Laser Melting Technology and Manufacturing of Accurate Thin Structures

2016 ◽  
Vol 862 ◽  
pp. 104-111
Author(s):  
Michal Ackermann ◽  
Jiří Šafka ◽  
Lukáš Voleský
Keyword(s):  
Selective Laser Melting ◽  
Scanning Speed ◽  
Laser Melting ◽  
Final Size ◽  
Minimal Thickness ◽  
Mean Size ◽  
Structural Consistency ◽  
Powder Particles ◽  
Fine Structures ◽  
Building Parameters

This paper deals with finding the building parameters for manufacturing of fine structures with regard to their size precision and structural consistency. Practical use of these structures can be found in areas such as microelectronics, fine mechanics and automotive. Very fine structures with thickness lower than 0.3 mm are very hard to be manufactured due to the limitations of Selective Laser Melting (SLM) technology. These limitations lie in building parameters including mean size and shape of the powder particles, diameter of laser spot and scanning speed. Practical part of the work consists of printing the testing matrices from AlSi12 material with different building parameters for each element. Final products are then evaluated using scanning electron microscope in order to verify final size and structural properties of the specimens. Thanks to these tests, it was possible to find actual border of the technology for given type of powder. Structure with minimal thickness and sufficient strength was found to be 0.21 mm. Moreover, the method for finding parameters for manufacturing of fine structures is applicable for other types of materials.

scholarly journals Design Rules for Hybrid Additive Manufacturing Combining Selective Laser Melting and Micromilling

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5753
Author(s):  
David Sommer ◽  
Babette Götzendorfer ◽  
Cemal Esen ◽  
Ralf Hellmann
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
High Speed ◽  
Hybrid Approach ◽  
Laser Melting ◽  
Support Design ◽  
Design Rules ◽  
Geometrical Accuracy ◽  
Design Engineers ◽  
A Charge

We report on a comprehensive study to evaluate fundamental properties of a hybrid manufacturing approach, combining selective laser melting and high speed milling, and to characterize typical geometrical features and conclude on a catalogue of design rules. As for any additive manufacturing approach, the understanding of the machine properties and the process behaviour as well as such a selection guide is of upmost importance to foster the implementation of new machining concepts and support design engineers. Geometrical accuracy between digitally designed and physically realized parts made of maraging steel and dimensional limits are analyzed by stripe line projection. In particular, we identify design rules for numerous basic geometric elements like walls, cylinders, angles, inclinations, overhangs, notches, inner and outer radii of spheres, chamfers in build direction, and holes of different shape, respectively, as being manufactured by the hybrid approach and compare them to sole selective laser melting. While the cutting tool defines the manufacturability of, e.g., edges and corners, the milling itself improves the surface roughness to Ra < 2μm. Thus, the given advantages of this hybrid process, e.g., space-resolved and custom-designed roughness and the superior geometrical accuracy are evaluated. Finally, we exemplify the potential of this particular promising hybrid approach by demonstrating an injection mold with a conformal cooling for a charge socket for an electro mobile.

Experimental investigation of melt pool behaviour during selective laser melting by high speed imaging

CIRP Annals ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 253-256 ◽  
Author(s):  
Tatsuaki Furumoto ◽  
Kyota Egashira ◽  
Kenta Munekage ◽  
Satoshi Abe
Keyword(s):  
Experimental Investigation ◽  
Selective Laser Melting ◽  
High Speed ◽  
Laser Melting ◽  
High Speed Imaging ◽  
Melt Pool

The Production and Subsequent Selective Laser Melting of AlSi12 Powder

2017 ◽  
Vol 265 ◽  
pp. 434-438 ◽  
Author(s):  
P.A. Lykov ◽  
A.O. Shults ◽  
K.A. Bromer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Selective Laser Melting ◽  
Gas Jet ◽  
Laser Melting ◽  
Size And Shape ◽  
Powder Particles ◽  
Scanning Electron

The paper studies the atomization of Al-based alloy AlSi12 in gas jet. Air was used as a spraying gas. The size and shape of powder particles were studied by using scanning electron microscopy and optical granulomorphometer. The obtained powder was used in selective laser melting.

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