Influence of temporal and spatial laser power modulation on melt pool dynamics

Gedicke, Jens; Olowinsky, Alexander; Artal, Javier; Gillner, Arnold

doi:10.2351/1.5061009

Cited by 17 publications

(6 citation statements)

References 1 publication

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“…The investigation of [16] focuses on welding of dissimilar materials using a pulsed Nd:YAG laser. Weld seam depth and temperature gradient in the melt pool are controlled by a temporal power modulation.…”

Section: Laser Beam Welding Of Electrical Contactsmentioning

confidence: 99%

Electrical Modelling and Investigation of Laser Beam Welded Joints for Lithium-Ion Batteries

et al. 2020

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The growing electrification of vehicles and tools increases the demand for low resistance contacts. Today’s batteries for electric vehicles consist of large quantities of single battery cells to reach the desired nominal voltage and energy. Each single cell needs a contacting of its cell terminals, which raises the necessity of an automated contacting process with low joint resistances to reduce the energy loss in the cell transitions. A capable joining process suitable for highly electrically conductive materials like copper or aluminium is the laser beam welding. This study contains the theoretical examination of the joint resistance and a simulation of the current flow dependent on the contacting welds’ position in an overlap configuration. The results are verified by examinations of laser-welded joints in a test bench environment. The investigations are analysing the influence of the shape and position of the weld seams as well as the influence of the laser welding parameters. The investigation identifies a tendency for current to flow predominantly through a contact’s edges. The use of a double weld seam with the largest possible distance greatly increases the joint’s conductivity, by leveraging this tendency and implementing a parallel connection. A simplistic increase of welded contact area does not only have a significantly smaller effect on the overall conductivity, but can eventually also reduce it.

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Section: Laser Beam Welding Of Electrical Contactsmentioning

confidence: 99%

Electrical Modelling and Investigation of Laser Beam Welded Joints for Lithium-Ion Batteries

et al. 2020

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“…There are some data available on welding an austenitic stainless steel type such as 1.4301 (AISI304) with high power new generation lasers. In the studies about welding with new generation lasers, it was confirmed that the fibre laser weld beads are narrow and deep, and their geometries are different from those of wineglass-shaped welds typical for CO 2 and Nd:YAG laser welds [2][3][4]. It was also found that weld becomes deeper and narrower with an increase in the power density.…”

Section: Lasers For Weldingmentioning

confidence: 93%

“…The field of applications will enlarge further with the use of optical means such as scanning optics, which is not fully exploited yet. There are some studies showing great potential in narrow gap laser welding [1] and to control the heat input and weld shape [2]. Many of the potential applications still have some restrictions in the use of laser welding, such as standard procedures and accepted practices for production and testing, ensuring acceptable weld quality.…”

Section: Introductionmentioning

confidence: 99%

The characteristics of high power fibre laser welding

Salminen

Piili

Purtonen

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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Laser welding has an ever growing role in manufacturing technology. Keyhole laser welding is the most important laser welding process in metal industry when exceeding the 1 mm weld penetration. This process uses efficiently the high energy density of a laser beam to vaporize and melt materials, thus producing a keyhole in the material via which the energy is brought to it. The requirements from customer side and the development of new materials have been giving justification for the development of new laser types suitable for material processing with ever higher power values. In contrast, the development of laser technologies has made it possible to build more powerful lasers with excellent beam properties and good electrical efficiency. New laser sources with good absorption and beam quality make the laser welding even more efficient when throughput and efficiency are considered. They show their ability to produce narrower welds with lower line energy. However, the validation of actual keyhole shape, size, and behaviour against the models is still lacking because of the difficulties in performing the measurements of the actual dimensions. It has been shown that the better the beam quality the higher the welding speed. When welding with high power, good beam quality, and wavelength close to 1000 nm, there are some obstacles to overcome, which are caused by high absorption and power density. Typically, problems, such as thermal lensing, can be avoided with proper parameter and tool selection. Typically, the size of the keyhole is according to the focal point size, and the stability of the keyhole plays a major role when considering the ability of the laser welding process to produce high quality welds.

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“…Measurements of the electrical resistance (four-point measurement, detailed description in Section 2.2) and tensile shear tests (based on DIN EN ISO 14273) of the generated weld seams were performed on these samples. spatial beam oscillation [9]. Large joining widths at the interface and low penetration depths into the lower Cu sheet were generated by welding with a fiber laser and spatial beam oscillation [3].…”

Section: Methodsmentioning

confidence: 99%

“…Homogeneous mixing of the two materials in the weld seam was demonstrated using a single-mode fiber laser and spatial beam oscillation [8]. Smaller mixing zones and less pores and cracks in the welds (compared to rectilinear welding) can be obtained using a pulsed laser and spatial beam oscillation [9]. Large joining widths at the interface and low penetration depths into the lower Cu sheet were generated by welding with a fiber laser and spatial beam oscillation [3].…”

Section: Introductionmentioning

confidence: 99%

Weld Seam Geometry and Electrical Resistance of Laser-Welded, Aluminum-Copper Dissimilar Joints Produced with Spatial Beam Oscillation

Jarwitz¹,

Fetzer²,

Weber³

et al. 2018

Metals

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Spatial beam oscillation during laser beam welding of aluminum to copper was investigated. The beam was spatially oscillated perpendicular to the direction of feed in a sinusoidal mode. The influence of the oscillation amplitude and frequency on the weld seam geometry and the implications on the electrical resistance of the joints was investigated. It was found that spatial beam oscillation allows to set the welding depth and seam width virtually independent of each other. Furthermore, low welding depths into the lower copper sheet in combination with high ratios of seam width at the interface of the two sheets to welding depth into the lower copper sheet result in low electrical resistances of the welds. Low electrical resistances were found to correlate with high mechanical strengths of the welds.

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Influence of temporal and spatial laser power modulation on melt pool dynamics

Cited by 17 publications

References 1 publication

Electrical Modelling and Investigation of Laser Beam Welded Joints for Lithium-Ion Batteries

Electrical Modelling and Investigation of Laser Beam Welded Joints for Lithium-Ion Batteries

The characteristics of high power fibre laser welding

Weld Seam Geometry and Electrical Resistance of Laser-Welded, Aluminum-Copper Dissimilar Joints Produced with Spatial Beam Oscillation

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