Investigations on copper welding using a frequency-doubled disk laser and high welding speeds

Alter, Lukas; Heider, Andreas; Bergmann, J.P.

doi:10.1016/j.procir.2018.08.003

Cited by 22 publications

(9 citation statements)

References 8 publications

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“…A notch filter with a center wavelength of 514 ± 2 nm, as well as a shortpass filter with a cut-off wavelength of 750 nm, was used to block the processing laser, as well as the measuring laser of the OCT System. The selection of the process parameters was based on the investigations in Reference [5] to achieve welding depths of up to 1 mm as used in typical copper micro welding applications in different weld regimes. The focal position of the processing beam was set to be on the sample surface.…”

Section: Methodsmentioning

confidence: 99%

“…In latest developments, beam sources with shorter wavelength are reaching the required performance for laser micro welding of copper, opening up new possibilities. Using a green laser with a wavelength of 515 nm, the authors of Reference [5] were able to achieve comparable welding depth compared to state-of-the-art fiber micro welding processes. The use of shorter wavelengths in copper welding is beneficial due to an increased absorption of the laser beam in the material [6].…”

Section: Introductionmentioning

confidence: 99%

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OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

et al. 2021

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The transition of the powertrain from combustion to electric systems increases the demand for reliable copper connections. For such applications, laser welding has become a key technology. Due to the complexity of laser welding, especially at micro welding with small weld seam dimensions and short process times, reliable in-line process monitoring has proven to be difficult. By using a green laser with a wavelength of λ=515, the welding process of copper benefits from an increased absorption, resulting in a shallow and stable deep penetration welding process. This opens up new possibilities for the process monitoring. In this contribution, the monitoring of the capillary depth in micro copper welding, with welding depth of up to 1 , was performed coaxially using an optical coherence tomography (OCT) system. By comparing the measured capillary depth and the actual welding depth, a good correlation between two measured values could be shown independently of the investigated process parameters and stability. Measuring the capillary depth allows a direct determination of the present aspect ratio in the welding process. For deep penetration welding, aspect ratios as low as 0.35 could be shown. By using an additional scanning system to superimpose the welding motion with a spacial oscillating of the OCT beam perpendicular to the welding motion, multiple information about the process could be determined. Using this method, several process information can be measured simultaneously and is shown for the weld seam width exemplarily.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

et al. 2021

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“…Welding from Cu sheet is challenging in terms of higher reflectivity, thermal conductivity and melting temperature (1080 • C) in contrast to Al. Therefore, to weld from copper side high intensity or good absorption of laser light is a fundamental requirement [8][9][10]. Very less investigations are conducted in the analysis of welding from Cu to Al [7,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…This paper investigates welding of Cu-Al (Cu on top) with green laser wavelength of 515 nm. Welding of Cu with green laser wavelength improves the absorption of laser light and increases the process stability [9,10,13], in comparison to near-IR laser wavelength of 1030 nm. This paper exploits the higher solubility of Al in Cu, which is about 18.5 at.%.…”

Section: Introductionmentioning

confidence: 99%

Welding of Copper to Aluminium With Laser Beam Wavelength of 515 nm

Mathivanan¹,

Plapper²

2021

Preprint

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In laser joining of copper (Cu) and aluminum (Al) sheets, the Al sheet is widely chosen as the top surface for laser irradiation because of increased absorption of laser beam and lower melting temperature of Al in contrast to Cu. This research focus on welding from Cu side to Al sheet. The main objective of irradiating the laser beam from the copper side (Cu on top) is to exploit higher solubility of Al in Cu. A significantly lower laser power can be used with 515 nm laser in comparison to 1030 nm. In addition to low laser power, a stable welding is obtained with 515 nm. Because of this advantage, 515 nm is selected for the current research. By fusion of Cu and Al the two sheet metals are welded, with presence of beneficial Cu solid solution phase and Al+Al2Cu in the joint with the brittle phases intermixed between the ductile phase. Therefore the mixed composition strengthens the joint. However excessive mixing leads to formation of more detrimental phases and less ductile phases. Therefore optimum mixing must be maintained. Energy dispersive X-ray spectroscopy (EDS) analysis indicate that large amount of beneficial Cu solid solution and Al rich phases is formed in the strong joint. From the tensile shear test for a strong joint, fracture is obtained on the heat-affected zone (HAZ) of Al. Therefore the key for welding from copper side is to have optimum melt with beneficial phases like Cu and Al+ Al2Cu and the detrimental phases intermixed between the ductile phases

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“…To improve the welding quality, many methods have been studied such as wobbling welding [3] , laser pro-structured surface [4,5] , Cu-based nano-composite absorber [6] , laser power modulation [7] , and welding in vacuum [8,9] . On the other hand, the absorption of Cu also shows a strong wavelength dependence [2] , so the green laser (wavelength 532 nm, absorption coefficient of 40% at room temperature) [10][11][12] and blue semiconductor laser (wavelength 450 nm, absorption coefficient of 67% at room temperature) [13] have been applied to Cu welding, and improved results were obtained. However, the cost of both green and blue lasers is still very high.…”

Section: Introductionmentioning

confidence: 99%

Micro-spot-welding of copper sheets with an IR vortex beam

Wang

Qin

et al. 2022

中国光学快报

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Copper welding with an infrared (IR) Gaussian laser beam usually shows obvious instability, spatters, and worse surface morphology due to the Gaussian distribution, temperature-dependent IR absorption, and high thermal conductivity in copper. In this paper, the IR quasi-continuous-wave Gaussian beam was converted into a vortex ring beam with a phase-plate and then applied to the micro-spot-welding of copper sheets. The welding with the vortex beam demonstrated a significantly improved welding performance, smoother surface morphology, and higher welding stability. Besides, no spatters appeared in the welding process.

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Investigations on copper welding using a frequency-doubled disk laser and high welding speeds

Cited by 22 publications

References 8 publications

OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

OCT Capillary Depth Measurement in Copper Micro Welding Using Green Lasers

Welding of Copper to Aluminium With Laser Beam Wavelength of 515 nm

Micro-spot-welding of copper sheets with an IR vortex beam

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