Process efficiency measurements in the laser engineered net shaping process

Unocic, Raymond R.; DuPont, J. N.

doi:10.1007/s11663-004-0104-7

Cited by 125 publications

(40 citation statements)

References 6 publications

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“…The transfer efficiency of the LENS unit was previously measured to be g~0.5. [20] Weld passes were conducted with absorbed powers (P) of 120, 180, and 250 W at travel speeds (S) of 1, 6, 24, and 47 mm/s. Welds were conducted along the [100], [110], and [120] crystal directions along the (001) crystal plane.…”

Section: Methodsmentioning

confidence: 99%

Stray Grain Formation in Welds of Single-Crystal Ni-Base Superalloy CMSX-4

Anderson

DuPont

DebRoy

2009

Metall Mater Trans A

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Autogenous welds on the single-crystal (SX) alloy CMSX-4 were prepared over a wide range of welding parameters and processes to investigate the formation and behavior of stray grains (SGs). The quantity and location of SGs in the welds were analyzed by orientation imaging microscopy (OIM). Heat-and fluid-flow modeling was conducted to understand the influence of welding parameters on the local solidification conditions and resultant SG formation tendency.The results indicate that constitutional supercooling and SG formation are generally reduced in low-power, high-travel-speed welds. Because of the complex effect of travel speed on temperature gradient and solidification velocity, the worst conditions for SG formation in alloy CMSX-4 for the conditions examined here occur at intermediate travel speeds of~6 mm/s. These findings were corroborated with heat-transfer/fluid-flow modeling simulations that were coupled with SG predictions. These calculations also indicate that SG formation will be greatest where different regions of dendrite growth intersect, due to the so-called off-axis heat flow. For a given set of welding conditions, the amount of SGs will also vary with substrate orientation. This effect is attributed to differences in the number and location of dendrite growth intersection regions within the melt pool that occur with changes in substrate orientation.

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Section: Methodsmentioning

confidence: 99%

Stray Grain Formation in Welds of Single-Crystal Ni-Base Superalloy CMSX-4

Anderson

DuPont

DebRoy

2009

Metall Mater Trans A

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“…Laser is commonly used as the energy source in AM system. However, it has very poor energy efficiency (2% -5%) [15]. Electron beam has a slightly higher energy efficiency (15% -20%), but it requires a high vacuum working environment [16].…”

Section: Introductionmentioning

confidence: 99%

A multi-bead overlapping model for robotic wire and arc additive manufacturing (WAAM)

Ding

Pan

Cuiuri

et al. 2015

Robotics and Computer-Integrated Manufacturing

410

132

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Wire and arc additive manufacturing (WAAM) is a promising alternative to traditional subtractive manufacturing for fabricating large aerospace components that feature high buy-to-fly ratio. Since the WAAM process builds up a part with complex geometry through the deposition of weld beads on a layer-by-layer basis, it is important to model the geometry of a single weld bead as well as the multi-bead overlapping process in order to achieve high surface quality and dimensional accuracy of the fabricated parts. This study firstly builds models for a single weld bead through various curve fitting methods. The experimental results show that both parabola and cosine functions accurately represent the bead profile. The overlapping principle is then detailed to model the geometry of multiple beads overlapping together. The tangent overlapping model (TOM) is established and the concept of the critical centre distance for stable multi-bead overlapping processes is presented. The proposed TOM is shown to provide a much better approximation to the experimental measurements when compared with the traditional flat-top overlapping model (FOM). This is critical in process planning to achieve better geometry accuracy and material efficiency in additive manufacturing. Abstract: Wire and arc additive manufacturing (WAAM) is a promising alternative to traditional subtractive manufacturing for fabricating large aerospace components that feature high buy-to-fly ratio. Since the WAAM process builds up a part with complex geometry through the deposition of weld beads on a layer-by-layer basis, it is important to model the geometry of a single weld bead as well as the multi-bead overlapping process in order to achieve high surface quality and dimensional accuracy of the fabricated parts. This study firstly builds models for a single weld bead through various curve fitting methods. The experimental results show that both parabola and cosine functions accurately represent the bead profile. The overlapping principle is then detailed to model the geometry of multiple beads overlapping together. The Tangent Overlapping Model (TOM) is established and the concept of the critical centre distance for stable multi-bead overlapping processes is presented. The proposed TOM is shown to provide a much better approximation to the experimental measurements when compared with the traditional Flat-top Overlapping Model (FOM). This is critical in process planning to achieve better geometry accuracy and material efficiency in additive manufacturing.

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“…The focus was the identification of laser energy transfer efficiency or power distribution routes during the deposition process. However, the energy input and distribution were obtained through the indirect measurement and modeling method [20][21][22]. Very few reports have quantitatively analyzed the energy consumption of LENS, much less the effects of input variables on the overall energy consumption during the laser deposition process.…”

Section: Introductionmentioning

confidence: 99%

Energy Consumption and Saving Analysis for Laser Engineered Net Shaping of Metal Powders

et al. 2016

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Abstract:With the increasing awareness of environmental protection and sustainable manufacturing, the environmental impact of laser additive manufacturing (LAM) technology has been attracting more and more attention. Aiming to quantitatively analyze the energy consumption and extract possible ways to save energy during the LAM process, this investigation studies the effects of input variables including laser power, scanning speed, and powder feed rate on the overall energy consumption during the laser deposition processes. Considering microhardness as a standard quality, the energy consumption of unit deposition volume (ECUDV, in J/mm 3 ) is proposed as a measure for the average applied energy of the fabricated metal part. The potential energy-saving benefits of the ultrasonic vibration-assisted laser engineering net shaping (LENS) process are also examined in this paper. The experimental results suggest that the theoretical and actual values of the energy consumption present different trends along with the same input variables. It is possible to reduce the energy consumption and, at the same time, maintain a good part quality and the optimal combination of the parameters referring to Inconel 718 as a material is laser power of 300 W, scanning speed of 8.47 mm/s and powder feed rate of 4 rpm. When the geometry shaping and microhardness are selected as evaluating criterions, American Iron and Steel Institute (AISI) 4140 powder will cause the largest energy consumption per unit volume. The ultrasonic vibration-assisted LENS process cannot only improve the clad quality, but can also decrease the energy consumption to a considerable extent.

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Process efficiency measurements in the laser engineered net shaping process

Cited by 125 publications

References 6 publications

Stray Grain Formation in Welds of Single-Crystal Ni-Base Superalloy CMSX-4

Stray Grain Formation in Welds of Single-Crystal Ni-Base Superalloy CMSX-4

A multi-bead overlapping model for robotic wire and arc additive manufacturing (WAAM)

Energy Consumption and Saving Analysis for Laser Engineered Net Shaping of Metal Powders

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