Numerical modelling and experimental validation of the effect of laser beam defocusing on process optimization during fiber laser welding of automotive press-hardened steels

Seam tracking is significant to obtain good welding quality. Aiming at establishing a model to detect and calculate the seam tracking offset during high-power fiber laser welding of Type 304 austenitic stainless steel plate butt joint welding, an infrared sensitive high-speed camera arranged off-axis orientation of laser beam was applied to capture the dynamic thermal images of molten pool. Through analyzing the infrared image, the actual position of the workpiece gap in the image was obtained. Least squares method was used to determine the precise position of the actual workpiece gap. A model that calculated the deviations between the workpiece gap and the laser beam was deduced. Also, the least squares method was used to fit the workpiece gap curve equation. The coordinate transformation technology was used and the welding seam equation was established. A linear model was obtained to detect the deviations between the workpiece gap and the welding seam. The welding experiments confirmed that the proposed welding seam equation was effective.

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Fiber Laser Welding of Dual-Phase and Bake-Hardened Steels

Strength of Materials ◽

10.1007/s11223-016-9789-5 ◽

2016 ◽

Vol 48 (4) ◽

pp. 481-486 ◽

Cited By ~ 2

Author(s):

P. Švec ◽

A. Schrek ◽

T. Csicsó

Keyword(s):

Laser Welding ◽

Fiber Laser ◽

Dual Phase ◽

Fiber Laser Welding ◽

Hardened Steels

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Dynamic interaction between a laser beam and keyhole front wall during fiber laser welding

Laser Physics ◽

10.1088/1555-6611/ab3c47 ◽

2019 ◽

Vol 29 (11) ◽

pp. 116003

Author(s):

S H Guo ◽

Q Wu ◽

J L Zou ◽

R S Xiao ◽

N Ha

Keyword(s):

Laser Beam ◽

Laser Welding ◽

Fiber Laser ◽

Dynamic Interaction ◽

Front Wall ◽

Fiber Laser Welding

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Seam Tracking Monitoring Based on Keyhole Features during High-Power Fiber Laser Welding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.314-316.932 ◽

2011 ◽

Vol 314-316 ◽

pp. 932-936

Author(s):

Xiang Dong Gao ◽

Ling Mo ◽

Seiji Katayama

Keyword(s):

Laser Beam ◽

Laser Welding ◽

Fiber Laser ◽

High Power ◽

High Speed ◽

Continuous Wave ◽

Welding Process ◽

Seam Tracking ◽

Fiber Laser Welding ◽

Welding Seam

Seam tracking is an important field to obtain good welding quality. During the high-power fiber laser welding, the laser beam focus must be controlled to track the welding seam accurately. A method of detecting the offset between the laser beam focus and the welding seam based on analyzing the keyhole features was researched during high-power fiber laser butt-joint welding of Type 304 austenitic stainless steel plates at a continuous wave fiber laser power of 10 kW. The joint gap width was less than 0.1mm. An infrared sensitive high speed camera was used to capture the thermal images of a molten pool in welding process. Two parameters called the keyhole centroid and keyhole shape were defined as the eigenvalues of seam tracking offset to determine the offset between the laser beam focus and the desired welding seam. The welding experiments confirmed that the offset between the laser beam focus and the welding seam could be monitored and estimated by the keyhole centroid and keyhole shape parameters effectively.

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Seam Tracking Monitoring during High-Power Fiber Laser Welding

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.201-202.69 ◽

2012 ◽

Vol 201-202 ◽

pp. 69-72

Author(s):

Xiang Dong Gao ◽

De Yong You

Keyword(s):

Laser Beam ◽

Laser Welding ◽

Fiber Laser ◽

High Power ◽

Molten Pool ◽

Weld Seam ◽

Continuous Wave ◽

Seam Tracking ◽

Primary Concern ◽

Fiber Laser Welding

Accurate detection of weld seam deviations from the desired path during laser welding process facilitates seam tracking monitoring and is thus of primary concern in performing successful weld. This paper proposes a novel method for real-time seam tracking monitoring during high-power fiber laser welding, as it investigates into the techniques of infrared image sensing and visual recognition. Molten pool images were taken by a high-speed camera arranged in the off-axis direction of laser beam. Accumulative grayscale variation based on a molten pool thermal distribution was extracted and used to determine the deviations between the laser beam focus and the weld seam center. The proposed algorithm was experimented on a butt joint laser welding of Type 304 stainless steel plates at a continuous wave fiber laser power of 10 kW.

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