Modeling of the thermal physical process and study on the reliability of linear energy density for selective laser melting

Xiang, Zhaowei; Yin, Ming; Dong, Guanhua; Mei, Xiaoqin; Yin, Guofu

doi:10.1016/j.rinp.2018.03.047

Cited by 30 publications

(19 citation statements)

References 40 publications

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“…e track formation changes from discontinuity to continuity, indicating that the energy density may not be a good indicator of controlling the molten pool morphology in micro-SLM. is observation confirms that the conclusion obtained by Bertoli et al [5] and Xiang et al [17] for the conventional SLM is also applicable for micro-SLM process. Figure 4 compares the surface roughness (Ra) at the center of the single track fabricated under different process parameters.…”

Section: Resultssupporting

confidence: 91%

Formation of SS316L Single Tracks in Micro Selective Laser Melting: Surface, Geometry, and Defects

Castagne

Song

et al. 2019

Advances in Materials Science and Engineering

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To fabricate complex parts with a fine resolution and smooth finish, micro selective laser melting (SLM) has been developed recently by combining three attributes: small laser beam spot, fine powder size, and thin layer thickness. This paper studies the effect of the micro-SLM process parameters on the single track formation of 316L stainless steel. The surface morphology, geometrical features, and defects have been analyzed in detail. The results highlight that laser power and scanning velocity have a significant effect on the formation of single tracks. The single tracks fabricated through micro-SLM with varying process parameters are classified into four types: no melting, discontinuous, continuous but unstable, and continuous tracks. Besides, the top surface of the tracks is observed with “double-crest” morphology, due to the high recoil pressure gradient generated by the extremely fine spot size. In addition, molten pool geometry (width, depth, and height) has been characterized to study the mode of the molten pool in micro-SLM. Finally, the occurrence of two typical defects within the tracks, keyhole pore and cavity at the edges, has been studied.

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Section: Resultssupporting

confidence: 91%

Formation of SS316L Single Tracks in Micro Selective Laser Melting: Surface, Geometry, and Defects

Castagne

Song

et al. 2019

Advances in Materials Science and Engineering

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“…When the temperature at the top surface reaches the melting point and dT/dt > 0, the top surface moves downward with a speed vs that depends on the initial powder porosity. Numerical models that take into account this phenomenon were found more realistic compared to previous ones above all in the prediction of the thermal gradient in vertical direction and molten pool depth [84]. Schwalbach et al [98] showed in their work how the amount of latent heat be negligible compared to the sensible heat.…”

Section: Thermal Resultsmentioning

confidence: 97%

“…As the powder reached the melting temperature, the upper sub-layer is removed by using for example the 'birth and death' numerical technique. In [84] the volume shrinkage is simulated by using the moving-mesh method. When the temperature at the top surface reaches the melting point and dT/dt > 0, the top surface moves downward with a speed vs that depends on the initial powder porosity.…”

Section: Thermal Resultsmentioning

confidence: 99%

“…where Tl, Ts and Tv are the liquidus, solidus and vaporization temperatures, respectively, and Lg and Lv are the latent heat (J/K) of fusion and vaporization. In their work, Xiang et al [84] distinguished also the emissivity of the powder layer from that of the dense material as follows:…”

Section: Modeling Of Materials Propertiesmentioning

confidence: 99%

“…where ε s is the emissivity of the solid material, A H is the area fraction of the surface that is occupied by the radiationemitting holes and εH is the emissivity of the hole. They depend on powder porosity () according to the following relations [84]:…”

Section: Modeling Of Materials Propertiesmentioning

confidence: 99%

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Understanding powder bed fusion additive manufacturing phenomena via numerical simulation

Ferro

Berto

Romanin

2020

Frattura Ed Integrità Strutturale

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The increasing interest in additively manufactured metallic parts from industry has issued a formidable challenge to the academic and scientific world that is asked to design new alloys, optimize process parameters and geometry as well as guarantee the reliability of a new generation of loadbearing components. Unfortunately, understanding the interaction between different phenomena associated to metal-additive manufacturing processes is a very difficult task. In this scenario, numerical modelling emerges as a valid technique to face problems related to the influence of process parameters on metallurgical and mechanical properties of additively manufactured components. This contribution is aimed at summarizing the most important outcomes about metal-additive manufacturing process obtained via numerical simulation with particular reference to powder bed fusion techniques. The fundamentals of additive manufacturing numerical simulation will be also explained in detail. Thermal, metallurgical as well as mechanical aspects are covered.

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Processability approach for laser powder bed fusion of metallic alloys

Castro-Espinosa,

Ruiz-Huerta

2023

Int J Adv Manuf Technol

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Processability refers to the ease of achieving the required component while maintaining mechanical performance and processing schedules, which are critical for determining the cost and efficiency of using a given material, from the raw condition to the final product of any manufacturing process. Components built using the laser powder bed fusion with metallic alloys (LPBF-M) process show variability in their mechanical performance, which can be attributed to a range of process parameters and characteristics of the powder material employed by each type of machine. These variations are currently hindering the adoption of this technology at the industrial level. This paper presents a processability approach that could be applied in the LPBF-M to evaluate the possibility of speeding up productivity and minimising the effect on the mechanical properties and relative density and is defined based on the process parameters and powder material characteristics that generate the melting pool and meet bonding criteria at a specific build rate. A case study is carried out with stainless steel 316 (SS316), although this processability analysis could be applied to any other alloy. The results show that a wide range of process parameters generates a suitable processability interval with different values of the build rate. It is also found that slow build rates give rise to less variability in the mechanical properties, while faster rates produce more variability; this is caused by a fast-growing melt pool due to the use of high scan velocities for the SS316 alloy under study.

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Modeling of the thermal physical process and study on the reliability of linear energy density for selective laser melting

Cited by 30 publications

References 40 publications

Formation of SS316L Single Tracks in Micro Selective Laser Melting: Surface, Geometry, and Defects

Formation of SS316L Single Tracks in Micro Selective Laser Melting: Surface, Geometry, and Defects

Understanding powder bed fusion additive manufacturing phenomena via numerical simulation

Processability approach for laser powder bed fusion of metallic alloys

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