Fundamentals of Energy Conversion and Dissipation in Powder Layers during Laser Micro Sintering

Streek, A.; Regenfuß, Peter; Exner, Horst

doi:10.1016/j.phpro.2013.03.159

Cited by 48 publications

(16 citation statements)

References 5 publications

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“…A number of experimental based investigations have studied the effect of powder size and scanning speed on the actual laser absorption by the powder. A ray tracing algorithm has been developed to describe laser power dissipation in depth of the powder in laser micro sintering process [16].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…As Refs. [16,18] suggested, radiation heat transfer is ignored in this model. Vaporization and melt pool phenomenon such as…”

Section: 1thermal Modelingmentioning

confidence: 99%

“…Estimating correct value for the OPD is very important for the numerical simulation of the process. Generally, scattering of the laser beam in powder bed may be occurred in four ways during interaction of laser beam and powder bed: transmission, forward scattering, backward scattering, and entirely absorption of the laser beam [16]. All these phenomena take part during the melting process.…”

Section: 3heat Source Modelingmentioning

confidence: 99%

“…properties [16]. The OPD is defined as the depth where the intensity of the laser energy reduces to 1/e ( 37%) of the intensity of the absorbed laser beam at the powder bed surface [25].…”

Section: 3heat Source Modelingmentioning

confidence: 99%

See 3 more Smart Citations

Finite Element Simulation of Selective Laser Melting process considering Optical Penetration Depth of laser in powder bed

et al. 2016

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Section: Accepted Manuscriptmentioning

confidence: 99%

“…As Refs. [16,18] suggested, radiation heat transfer is ignored in this model. Vaporization and melt pool phenomenon such as…”

Section: 1thermal Modelingmentioning

confidence: 99%

Section: 3heat Source Modelingmentioning

confidence: 99%

“…properties [16]. The OPD is defined as the depth where the intensity of the laser energy reduces to 1/e ( 37%) of the intensity of the absorbed laser beam at the powder bed surface [25].…”

Section: 3heat Source Modelingmentioning

confidence: 99%

See 2 more Smart Citations

Finite Element Simulation of Selective Laser Melting process considering Optical Penetration Depth of laser in powder bed

et al. 2016

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“…The powder bed in SLM machine has a high porosity as powder is spread freely without compression or heat treatment on the platform. used ray tracing algorithm to describe the laser energy absorption and conversion during laser sintering process, which could be regarded as a function of grain size, grain density, laser beam intensity and material properties [97]. It was reported that powder particles with small size also require increased laser energy penetration to form melting pool due to their high surface-to-volume ratio [98].…”

Section: Laser-powder Interactionmentioning

confidence: 99%

Selective laser melting of ceramic-based materials for dental applications

Mapar¹

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The employment ofthe Selective Laser Melting (SLM) technique in the processing o f ceramics has attracted attention recently. SLM is a powder-based AM process where powder spreading is one o f the fundamental. Therefore, a spray-drying process was chosen to improve powder properties to reach a proper powder for the SLM process. Also a dynamic powder characterisation methodology was used to investigate powder flow characteristic. A series o f SLM experiments were conducted using the spray-dried powder in three stages: single-track melting, single-layer melting and fabrication o f threedimensional (3D) blocks (multilayers). The objectives o f this set o f experiments were to establish the preliminary processing windows o f ceramics via SLM. Finally, multilayer or ceramic 3D blocks were experimented via SLM machine. However, the density o f the fabricated 3D parts was low and the parts were also fragile and unstable. These results showed that with current state o f technology, it is still a challenge to directly fabricate dense ceramic components using SLM. Following the insights obtained from these experiments, the critical challenges o f this project were identified and discussed, including ceramic powder layer deposition, laser-powder particles interaction, the dynamic melting and consolidation mechanism, process parameter optimisation and residual stress analysis ofthe ceramic materials processed with SLM.

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From pulsed to continuous wave emission in SLM with contemporary fiber laser sources: effect of temporal and spatial pulse overlap in part quality

Demir

Colombo

Previtali

2017

Int J Adv Manuf Technol

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In this work, the effect of pulse temporal and spatial overlapping is evaluated in selective laser melting (SLM). An SLM system operating with fiber laser in pulsed wave (PW) emission was employed. The test material was 18Ni300 maraging steel, which shows reduced process stability due to a high amount of vapour and spark generation during the process. The pulsation characteristics of contemporary power-modulated fiber lasers compared to previously employed Q-switched Nd:YAG systems are explained. Processing conditions are studied moving towards continuous wave (CW) by increasing the duty cycle with fixed fluence. The key quality aspects, namely part density and dimensional error, were evaluated and the robustness was assessed. The results demonstrate that with a limited amount of increase in duty cycle by 3%, part density can be improved, while the dimensional error increases. The results show that CW is preferable when fully dense large parts have to be obtained. On the other hand, operating in PW is convenient when thin struts as in lattice structure or micro and precise features are required

show abstract

Fundamentals of Energy Conversion and Dissipation in Powder Layers during Laser Micro Sintering

Cited by 48 publications

References 5 publications

Finite Element Simulation of Selective Laser Melting process considering Optical Penetration Depth of laser in powder bed

Finite Element Simulation of Selective Laser Melting process considering Optical Penetration Depth of laser in powder bed

Selective laser melting of ceramic-based materials for dental applications

From pulsed to continuous wave emission in SLM with contemporary fiber laser sources: effect of temporal and spatial pulse overlap in part quality

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