Study on the numerical simulation of laying powder for the selective laser melting process

Cao, Liu

doi:10.1007/s00170-019-04440-4

Cited by 30 publications

(11 citation statements)

References 22 publications

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“…In this study, the MSS powder was used to fabricate injection mold. Some alternative powders, such as 17-4 PH stainless steel, Al-Si alloy, Ni-Ti alloy , 304 stainless steel , 316-L stainless steel, CoCrMo [27], IN 718 alloy, Ti6Al 4 V [28], W-Ni-Cu [29], TC 4 [30], Ni [31], Al-Fe-V-Si [32], A357 [33], Cu-15Ni-8S [34], or Inconel 625 [35] could also be used to make functional components for industrial applications. Thus, molds, dies, automotive, aircraft, aerospace, or gear with high mechanical properties can be manufactured by MAM technology with above powders.…”

Section: Resultsmentioning

confidence: 99%

A low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels using optimum heat treatment process procedures

Kuo

Qiu

Yang

2021

Int J Adv Manuf Technol

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Metal additive manufacturing (MAM) provides lots of bene ts and potentials in manufacturing molds or dies with sophisticated conformal cooling channels. It is known that the conformal cooling technology provides effective cooling to reduce cycle time for increasing productivity. Ordinarily, mold inserts fabricated by general printing procedures will result in coolant leakage in the injection molding process.The yield in the manufacturing of fully dense injection molding tools was limited to the very narrow working widow. In addition, high costs of fully dense injection mold fabricated by MAM constitute the major obstacle to its application in the mold or die industry. In general, the high cost of MAM is approximately 50-70% more expensive than conventional computer numerical control machining. In this study, a low-cost and highly e cient method of reducing coolant leakage for direct metal printed injection mold with cooling channels was proposed. This new method employs general process parameters to manufacture the green injection mold rapidly and then uses optimum heat treatment (HT) procedures to improve microstructure of the green injection mold. The results of this study revealed that optimum HT procedures can prevent coolant leakage and save manufacturing time of the injection mold fabricated by direct metal laser sintering. The evolution mechanisms of microstructure were investigated experimentally. The save in the injection mold manufacture time about 67% can be obtained.

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Section: Resultsmentioning

confidence: 99%

A low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels using optimum heat treatment process procedures

Kuo

Qiu

Yang

2021

Int J Adv Manuf Technol

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“…The particle's motion follows Newton's second law, and the influencing factors include particle-particle collisions, particle-wall collisions, fluid drag force, gravity, buoyancy, and additional mass force, etc. The major difference between DPM and the common Discrete Element Method [27] (DEM) is that to improve the computational efficiency, DPM takes particle packages as the object of study, and each particle package contains several particles, which have the same size, velocity, and other properties. Since the underlying code of the denseParticleFoam solver has not been changed here, the specific CFD-DPM theoretical model can be found in the official documentation of OpenFOAM-v9 [25].…”

Section: Cfd-dpm Simulation Methodsmentioning

confidence: 99%

CFD–DPM Simulation Study of the Effect of Powder Layer Thickness on the SLM Spatter Behavior

Cao

Zhang

Meng

2022

Metals

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Selective Laser Melting (SLM) has significant advantages in manufacturing complex structural components and refining the alloy microstructure; however, spatter, as a phenomenon that accompanies the entire SLM forming process, is prone to problems such as inclusions, porosity, and low powder recovery quality. In this paper, a Computational Fluid Dynamics–Discrete Particle Method (CFD–DPM) simulation flow for predicting the SLM spatter behavior is established based on the open-source code OpenFOAM. Among them, the single-phase flow Navier–Stokes equation is used in the Eulerian framework to equivalently describe the effect of metal vapor and protective gas on the flow field of the forming cavity, and the DPM method is used in the Lagrangian framework to describe the metal particle motion, and the factors affecting the particle motion include particle–particle collision, particle–wall collision, fluid drag force, gravity, buoyancy force, and additional mass force. In addition, the equivalent volume force and fluid drag force are used to characterize the fluid–particle coupling interaction. For the spatter behavior and powder bed denudation phenomenon, the calculation results show that the spatter height and the drop location show a clear correlation, and the powder bed denudation phenomenon is caused by the high-speed gas flow, causing the surrounding gas to gather in the forming area, which in turn drives the motion of the powder bed particles. For the effect of powder layer thickness on spatter and powder bed denudation, the calculation results show that the effect of powder layer thickness on the number of spatters is large (when the thickness was increased from 50 μm to 100 μm, the number of spatters increased by 157%), but the effect on spatter height and drop location distribution is small. When the powder layer thickness is small, the width of the denudation zone is significantly larger, but when the powder layer reaches a certain thickness, the width of the denudation zone does not show significant changes. It should be noted that the presented model has not been directly validated by experiments so far due to the difficulty of tracking the large-scale motion of SLM spatter in real time by current experimental means.

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“…As a numerical calculation method for solving and analyzing the motion law and mechanical characteristics of complex discrete systems, DEM can be used to characterize collision and friction behaviors in particle systems [45]. The LPBF spreading powder process was predicted here based on DEM [39], and the calculation process was divided into the following four steps: (a) The metal particles were regarded as elastic spheres with contact friction effect, and the particle size distribution curve of the powder was obtained by means of experimental methods or literature data; (b) A particle cluster was generated in a certain space above the substrate and spread loosely on the substrate under the action of gravity; (c) The roller was moved to spread the powder, during which the contact friction between the roller and the particles and between the particles were considered; (d) After spreading powder, the sphere center coordinates and radius of the powder bed particles were derived.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…As a typical quantitative research method, numerical simulation has become a powerful auxiliary method for analyzing LPBF process [27][28][29]. At present, the simulation research for the LPBF process is mainly based on the following three scales: (a) macroscopic-scale, that is, by establishing a simpli ed model, the transition between the three phases "powder bed-metal liquid-phase-metal solid-phase" is equivalently handled to obtain the temperature eld and stress eld distribution [30][31][32][33][34][35]; (b) Mesoscopic-scale, that is, the heating effect of the laser on the metal particles is directly calculated to describe the dynamic behavior of the mesoscopic molten pool [36][37][38][39][40][41]; (c) Microscopic-scale, that is, based on the thermal eld information of the LPBF process, the growth behavior of dendrites is described [42,43]. Yuan et al [44] predicted the LPBF process at different scanning speeds based on the mesoscopic scale, and identi ed three mesoscopic molten pool states (unstable state, transition state, and steady state), and found that a stable molten pool with a small recessed area was bene cial to obtain a higher density part.…”

Section: Introductionmentioning

confidence: 99%

“…Yuan et al [44] predicted the LPBF process at different scanning speeds based on the mesoscopic scale, and identi ed three mesoscopic molten pool states (unstable state, transition state, and steady state), and found that a stable molten pool with a small recessed area was bene cial to obtain a higher density part. The obtained simulation research results [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] provide a way to predict the temperature, molten pool ow, stress and other information of the LPBF process, but the current simulation research lacks a comprehensive analysis of the in uence of process parameters on the LPBF multi-layer and multi-path process based on the mesoscopic scale, which is also the focus of this paper.…”

Section: Introductionmentioning

confidence: 99%

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Mesoscopic-Scale Numerical Investigation Including the Inuence of Process Parameters on LPBFMulti-Layer Multi-Path Formation

Cao¹

2021

Computer Modeling in Engineering &Amp; Sciences

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As a typical laser additive manufacturing technology, laser powder bed fusion (LPBF) has achieved demonstration applications in aerospace, biomedical and other elds. However, how to select process parameters quickly and reasonably is still the main concern of LPBF production. In order to quantitatively analyze the in uence of di erent process parameters (laser power, scanning speed, hatch space and layer thickness) on the LPBF process, the multilayer and multi-path forming process of LPBF was predicted based on the open-source discrete element method framework Yade and the open-source nite volume method framework OpenFOAM. Based on the design of experiments method, a four-factor three-level orthogonal test scheme was designed, and the porosity and surface roughness data of each calculation scheme were extracted. By analyzing the orthogonal test data, it was found that as the laser power increased, the porosity decreased, and as the scanning speed, hatch space, and layer thickness increased, the porosity increased. In addition, the in uence of laser power and scanning speed on surface roughness showed a trend of decreasing rst and then increasing, while the in uence of scanning distance and layer thickness on surface roughness showed a monotonous increasing trend. The order of the in uence of each process parameter on porosity was: scanning speed > laying thickness > laser power > hatch space, and the order of the in uence of each process parameter on surface roughness was: hatch space > layer thickness > laser power > scanning speed. So the porosity of the part is most sensitive to scanning speed, and the surface roughness is the most sensitive to hatch space. The above conclusions are expected to provide process control basis for actual LPBF production of the 316L stainless steel alloy.

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Study on the numerical simulation of laying powder for the selective laser melting process

Cited by 30 publications

References 22 publications

A low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels using optimum heat treatment process procedures

A low-cost and highly efficient method of reducing coolant leakage for direct metal printed injection mold with cooling channels using optimum heat treatment process procedures

CFD–DPM Simulation Study of the Effect of Powder Layer Thickness on the SLM Spatter Behavior

Mesoscopic-Scale Numerical Investigation Including the Inuence of Process Parameters on LPBFMulti-Layer Multi-Path Formation

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