Temperature and stress analysis and simulation in fractal scanning-based laser sintering

Ma, Lifeng; Bin, Hongzan

doi:10.1007/s00170-006-0665-5

Cited by 91 publications

(62 citation statements)

References 10 publications

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“…With regard to the second phenomenon, the melted top layers shrink due to the thermal contraction of the material; but this movement is inhibited by the lower layers, resulting in a tensile stress in the uppermost layer and compressive stresses below [24]. Side view of SLM part experiencing temperature gradient mechanism; adapted from [24] Three main heat transfer mechanisms can be identified during the SLM process [28], [29]: laser radiation, convection, and conduction. The largest heat loss mechanism is through convection at the top surface with the ambient atmosphere of the SLM system [28], [29].…”

Section: Stress Induction Mechanismsmentioning

confidence: 99%

“…Side view of SLM part experiencing temperature gradient mechanism; adapted from [24] Three main heat transfer mechanisms can be identified during the SLM process [28], [29]: laser radiation, convection, and conduction. The largest heat loss mechanism is through convection at the top surface with the ambient atmosphere of the SLM system [28], [29]. In the third phenomenon, the top surface of the exposed layer experiences a faster cooling rate through convection than the bottom of the layer through conduction.…”

Section: Stress Induction Mechanismsmentioning

confidence: 99%

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The Effects of Selective Laser Melting Scan Strategies on Deviation of Hybrid Parts

Hagedorn-Hansen¹,

Bezuidenhout²,

Dimitrov³

et al. 2017

SAJIE

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The use of additive manufacturing to produce intricate part geometries in the aerospace, medical, and tool-and-die industries is increasingly incorporated in manufacturing process chains. However, the high costs, long production times, and material integrity issues associated with additive manufacturing technologies such as selective laser melting make the process suitable only for certain applications. In order to reduce selective laser melting production costs for selected parts, a combination of selective laser melting and milling can be used. Metal parts produced with this method are referred to as hybrid parts. A challenge in producing hybrid parts is to reduce the geometrical deviation due to processinduced warping. This paper discusses the effects of various laser scan strategies on the deviation of hybrid parts. A newly developed scan strategy is experimentally compared with its commercial counterpart with regard to as-built part warping and porosity. The novel strategy resulted in a significant reduction in warping and porosity. OPSOMMINGDie benutting van toevoegingsvervaardiging vir die produksie van komplekse onderdeel geometrieë in die lugvaart, mediese, en werktuig industrieë word toenemend geïnkorporeer in vervaardigingsproseskettings. Gepaardgaande hoë kostes, lang produksietye, en materiaal integriteitstekortkominge met toevoegingsvervaardiging tegnologieë soos selektiewe laser smelting veroorsaak dat die proses slegs uitvoerbaar is vir sekere toepassings. Ten einde selektiewe laser smelting produksiekoste te verminder vir geselekteerde onderdele, kan 'n kombinasie van selektiewe laser smelting en freesmasjinering geïmplementeer word. Metaal onderdele wat met so kombinasie geproduseer word, word na verwys as hibried onderdele. 'n Uitdaging in die vervaardiging van hibried onderdele is om geometriese afwyking deur skeeftrekking wat deur die proses veroorsaak word, te verminder. Hierdie artikel bespreek die effekte van verskeie laser skandeer strategieë op die afwyking van hibried onderdele. 'n Nuut ontwikkelde skandeer strategie is eksperimenteel vergelyk met 'n kommersiële eweknie met betrekking tot skeeftrekking en porositeit. Die skeeftrekking en porositeit van die nuut uitgevonde strategie is beduidend laer.

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Section: Stress Induction Mechanismsmentioning

confidence: 99%

Section: Stress Induction Mechanismsmentioning

confidence: 99%

The Effects of Selective Laser Melting Scan Strategies on Deviation of Hybrid Parts

Hagedorn-Hansen¹,

Bezuidenhout²,

Dimitrov³

et al. 2017

SAJIE

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show abstract

“…Temperature distribution and temperature gradient variation along x-and y-axis in metal laser sintering were investigated by R. B. Patil [10]. The decreased transient stress of a layer with fractal scan mode in the process of indirect SLS was pointed out by L. Ma [11]. However, the effects of various processing parameters on the temperature field of SLM process were not considered in the above-reported literature.…”

Section: Introductionmentioning

confidence: 98%

Effects of processing parameters on the temperature field of selective laser melting metal powder

Shi

Liu

et al. 2009

Powder Metall Met Ceram

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Based on temperature-dependent thermophysical parameters and nonlinear phase transformation from powder to liquid, a three-dimensional transient thermal finite model of selective laser melting process is developed. Commercial ANSYS software is used to simulate the distribution of the temperature field in selective laser melting. The simulation results show that a lower scan speed, higher laser power, and a lower scan interval enable much higher maximum temperature in the powder bed and wider scan track width. The scan modes also have great influence on the temperature field. Temperature in the powder bed experiences fluctuant variation with transverse scan mode in contrast with moderate variation with lengthwise scan mode. The simulated results are compared with the experimental results and good agreement is found in scan track width.

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“…Thus to vary the volume fraction or porosity of material being deposited in a unit area and thereby to control the porosity, location-controlled density raster tool paths are proposed using fractal curves in the present work. Fractal curves have been studied for raster tool path generation in LM (Soo and Yu 2003, Yang et al 2003, Ma and Bin 2006. Soo and Yu (2003) have developed a radial-annular tree data structure to represent self-similar objects.…”

Section: Related Workmentioning

confidence: 99%

Fractal raster tool paths for layered manufacturing of porous objects

Kumar

Pandithevan

Ambatti

2009

Virtual and Physical Prototyping

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The present work describes an approach for layered manufacturing (LM) of porous objects using an appropriate modelling scheme, a pre-processing algorithm for slicing and a raster tool path generation based on the porosity information. Initially an overall framework of modelling and data transfer that includes controlled porosity information apart from the external geometry of porous objects and its transfer for LM is presented. A novel raster path generation methodology using space-filling fractal curves for LM of porous models is presented later. Specifically, the geometry and space-filling characteristics of fractal curves are studied for application to raster tool path generation in LM. Finally, boundary-constrained raster patterns are generated based on the surface geometry. The resulting data can be translated into a machine language file that can be imported by an LM system. Case studies are presented to illustrate the efficacy of this approach.

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Temperature and stress analysis and simulation in fractal scanning-based laser sintering

Cited by 91 publications

References 10 publications

The Effects of Selective Laser Melting Scan Strategies on Deviation of Hybrid Parts

The Effects of Selective Laser Melting Scan Strategies on Deviation of Hybrid Parts

Effects of processing parameters on the temperature field of selective laser melting metal powder

Fractal raster tool paths for layered manufacturing of porous objects

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