Laser beam welding setup for the coaxial combination of two laser beams to vary the intensity distribution

Möbus, M.; Woizeschke, Peer

doi:10.1007/s40194-021-01234-9

“…Multi-spot welding was demonstrated to increase the process stability. Spot-in-spot techniques showed for example a more stable keyhole [9]. Diffractive static beam shaping enables nowadays the creation of almost all kinds of beam shapes at high laser power.…”

Section: Beam Shapingmentioning

confidence: 99%

Impact of melt flow and surface tension on gap bridging during laser beam welding

Volpp

¹

2023

Preprint

0

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Laser beam welding is an essential technology to enable the transformation to enforce e-mobility. When manufacturing light weight structures like the chassis, precision, speed, quality and low deformation can be expected when using the laser beam as a welding heat source. However, the laser beam is typically used at small dimensions and can fail to transfer its energy to the joining partners when the gap between them becomes large. Beam shaping technologies have developed in the last years to be flexibly used for high-power processes and provide an opportunity to alter the energy input and thereby improve the welding quality and gap bridgability. In this work, multi-spot beam shaping was analyzed using up to nine spots. Experiments were performed using different beam shapes in order to redistribute the energy input, recording the process using high-speed imaging for detection of melt pool dimensions. Those were used as input for a simplified analytical model predicting the process collapse based on the available melt material. Several beam shapes created melt pools that support the material availability behind the keyhole(s). Numerical simulations showed that directed melt flows induced by the keyhole(s) can increase the gap bridgability.

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“…Multi-spot welding was demonstrated to increase the process stability. Spot-in-spot techniques showed for example a more stable keyhole [10]. Diffractive static beam shaping enables nowadays the creation of almost all kinds of beam shapes at high laser power.…”

Section: Beam Shapingmentioning

confidence: 99%

Impact of Melt Flow and Surface Tension on Gap Bridging During Laser Beam Welding

Volpp

¹

2023

Lasers Manuf. Mater. Process.

1

0

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Laser beam welding is an essential technology to enable the transformation to enforce e-mobility. When manufacturing light weight structures like the chassis, precision, speed, quality and low deformation can be expected when using the laser beam as a welding heat source. However, the laser beam is typically used at small dimensions and can fail to transfer its energy to the joining partners when the gap between them becomes large. Beam shaping technologies have developed in the last years to be flexibly used for high-power processes and provide an opportunity to alter the energy input and thereby improve the welding quality and gap bridgability. In this work, multi-spot beam shaping was analyzed using up to nine spots. Experiments were performed using different beam shapes in order to redistribute the energy input, recording the process using high-speed imaging for detection of melt pool dimensions. Those were used as input for a simplified analytical model predicting the process collapse based on the available melt material. Several beam shapes created melt pools that support the material availability behind the keyhole(s). Numerical simulations showed that directed melt flows induced by the keyhole(s) can increase the gap bridgability.

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“…The authors conclude that to avoid hot cracking, less filler metal must be added to the weld. Some works were performed to improve the performance of laser beam by using a set up for the coaxial combination of two laser beams to vary the intensity distribution [16], or by using hollow beam welding on bead-on-plate. Authors noted that when hollow beam welding is applied on 304 stainless steel sheets the spatters and the pores can be effectively suppressed, and the cooling rate during solidification process is increased and the austenite obtained is finer [17].…”

Section: Introductionmentioning

confidence: 99%

Laser Weld Aspect Optimization of Thin AISI 316 SS Using RSM in Relation with Welding Parameters and Sulfur Content

Touileb,

Attia,

Djoudjou

et al. 2023

Metals

2

0

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A quantitative and qualitative study of the effect of laser (light amplification by stimulated emissions of radiation) welding parameters, such as focus point, welding speed, power beam and shield gas on bead profile in relation with microchemistry compositions differences of two thin AISI 316 industrial stainless steel casts have been studied. One cast contains 60 ppm (0.006%) of sulfur considered as high sulfur content and the other one contains 10 ppm (0.001 %) sulfur which can be considered as low sulfur content. A set of 27 tests were carried out by combining three welding speeds (1500, 3000, and 4500 mm/min), three shield gases (helium (He), mixture of 40% helium and 60% argon (Ar) and mixture of 70% helium and 30% argon) with flow rate of 15 L/min, and three focal lengths (+2, +7, and +12 mm). The depth, aspect ratio (the ratio between the penetration depth weld and the weld width) and the bead cross section profile are investigated using response surface methodology (RSM). Linear and quadratic polynomial models for predicting the weld bead geometry were developed. The results of the preliminary validation indicated that the proposed models predict the responses adequately. The geometry of the welded area was analyzed using optical microscopy, and correlations between weld morphology (depth, weld aspect parameter and weld area) and welding parameters were performed. For the cast 316 HS (high sulfur content), the main input factor influencing the depth weld (Yd) is the focus point with a contribution up to 19.32. On the other hand, the main input factor affecting the depth weld (Yd) of the cast 316 LS (low sulfur content) is the combination effect of focus point and power input energy with contribution up to 10.65%. Sulfur as the surfactant element contributes to determining the laser weld bead shape up to 71% when the welds are partially penetrated and diminishes to 50% when the welds are fully penetrated with the occurrence of the keyhole mechanism.

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Laser beam welding setup for the coaxial combination of two laser beams to vary the intensity distribution

Cited by 10 publications

References 7 publications

Impact of melt flow and surface tension on gap bridging during laser beam welding

Impact of melt flow and surface tension on gap bridging during laser beam welding

Impact of Melt Flow and Surface Tension on Gap Bridging During Laser Beam Welding

Laser Weld Aspect Optimization of Thin AISI 316 SS Using RSM in Relation with Welding Parameters and Sulfur Content

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