Laser direct metal deposition: theory and applications in manufacturing and maintenance

Pinkerton, Andrew J.

doi:10.1533/9781845699819.6.461

Cited by 42 publications

(41 citation statements)

References 86 publications

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“…The direct metal deposition (DMD) laser technique is a recentlydeveloped manufacturing technique that allows obtaining drafts of complex metallic parts from a three dimensional CAD model as reminded by Pinkerton (2010), even if technical issues still exist (stability of the DMD, process control, geometrical limits) before a widespread industrialization. The process uses a high power laser (usually Nd:YAG, fiber or diode laser) focused onto a metallic substrate to generate a molten pool, where a coaxial powder feeding increases the material volume and contributes to the formation of a solid layer.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, as reminded by Pinkerton (2010), one can assume that melt-pool stability depends on various internal forces (Marangoni flow, gravitational forces) or external forces (gas pressure, recoil forces near vaporization point, dynamic forces applied by the projected powder grains) applied on the molten metal. For instance, negative thermo-capillary coefficients d /dT (N/m K) are expected to provoke centrifugal Marangoni fluid flow directed away from the melt-pool center.…”

Section: Introductionmentioning

confidence: 99%

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Influence of various process conditions on surface finishes induced by the direct metal deposition laser technique on a Ti–6Al–4V alloy

Gharbi

Peyre

Gorny

et al. 2013

Journal of Materials Processing Technology

140

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tThe direct metal deposition (DMD) with laser is a free-form metal deposition process for manufacturing dense pieces, which allows generating a prototype or small series of near net-shape structures. One of the most critical issues is that produced pieces have a deleterious surface finish which systematically requires post machining steps. This problem has never been fully addressed before. The present work describes investigations on the DMD process, using an Yb-YAG disk laser, and a widely used titanium alloy (Ti-6Al-4V) to understand the influence of the main process parameters on the surface finish quality. The focus of our work was: (1) to understand the physical mechanisms responsible for deleterious surface finishes, (2) to propose different experimental solutions for improving surface finish.In order to understand the physical mechanisms responsible for deleterious surface finishes, we have carried out: (1) a precise characterization of the laser beam and the powder stream; (2) a large number of multi-layered walls using different process parameters (P(W), V(m/min), D m (g/min), Gaussian or uniform beam distribution); (3) a real time fast camera analysis of melt pool dynamics and melt-pool -powder stream coupling; (4) a characterization of wall morphologies versus process parameters using 2D and 3D profilometry.The results confirm that surface degradation depends on two distinct aspects: the sticking of nonmelted or partially melted particles on the free surfaces, and the formation of menisci with more or less pronounced curvature radii. Among other aspects, a reduction of layer thickness and an increase of melt-pool volumes to favor re-melting processes are shown to have a beneficial effect on roughness parameters. Last, a simple analytical model was proposed to correlate melt-pool geometries to resulting surface finishes.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of various process conditions on surface finishes induced by the direct metal deposition laser technique on a Ti–6Al–4V alloy

Gharbi

Peyre

Gorny

et al. 2013

Journal of Materials Processing Technology

140

View full text Add to dashboard Cite

show abstract

“…The LOF was formed in the specimens because of a smaller amount of specific energy applied during the DED process 16) . It caused the metal powder incompletely melted owing to lower melt pool temperature, and this condition led to an insufficient penetration depth to the previous layer 4,17) , consequently, introducing an interlayer porosity at the interface of deposited layers.…”

Section: Discussionmentioning

confidence: 99%

Effect of Process Parameters on the Formation of Lack of Fusion in Directed Energy Deposition of Ti-6Al-4V Alloy

Nursyifaulkhair

Park

Baek

et al. 2019

Journal of Welding and Joining

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The effect of different process parameters on the formation of lack of fusion (LOF) in Ti-6Al-4V alloy fabricated using DED was studied. The specific energy was calculated to evaluate the minimal amount of required energy to avoid LOF. The results showed that a specific energy smaller than 2700 J.g-1 led to the formation of LOF; however, a higher specific energy was able to successfully prevent the defect. A smaller amount of specific energy resulted in inadequate heat, which was too low to completely melt the metal powder, and resulted in insufficient penetration depth. Subsequently, LOF was observed between the interface of the deposited layers. Furthermore, a higher powder feed rate had a more significant effect on the formation of LOF than higher laser power.

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“…The direct metal deposition (DMD) or laser assisted direct fabrication technique is an attractive manufacturing technique that has been investigated since more than a decade, and allows obtaining sound and near net shape metallic parts from a three dimensional CAD model as indicated by Kobryn and Semiatin (2001), or more recently by Pinkerton (2010). In the DMD process, a high power focused laser beam (usually Nd:YAG, fiber or diode laser) is used as a heat source to selectively generate a molten pool on a substrate, where a coaxial powder feeding increases the material volume and contributes to the formation of a solid layer.…”

Section: Introductionmentioning

confidence: 99%

“…A common thought is that optimum surface finishes are mostly expected when using thin and stable deposited layers, when limiting melt pool disturbance, but without more precisions concerning process parameters, and melt pool shapes and dynamics. Moreover, as reminded by Pinkerton (2010), one can assume that melt pool stability depends on various internal forces (Marangoni flow, gravitational forces) or external forces (gas pressure, recoil forces near vaporization point, dynamic forces applied by the projected powder grains) applied on the molten metal.…”

Section: Introductionmentioning

confidence: 99%

Influence of a pulsed laser regime on surface finish induced by the direct metal deposition process on a Ti64 alloy

Gharbi¹,

Peyre²,

Gorny³

et al. 2014

Journal of Materials Processing Technology

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Laser direct metal deposition: theory and applications in manufacturing and maintenance

Cited by 42 publications

References 86 publications

Influence of various process conditions on surface finishes induced by the direct metal deposition laser technique on a Ti–6Al–4V alloy

Influence of various process conditions on surface finishes induced by the direct metal deposition laser technique on a Ti–6Al–4V alloy

Effect of Process Parameters on the Formation of Lack of Fusion in Directed Energy Deposition of Ti-6Al-4V Alloy

Influence of a pulsed laser regime on surface finish induced by the direct metal deposition process on a Ti64 alloy

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