Extraction of Weld Pool Width Feature Based on Visual Sensing during High-Power Fiber Laser Welding

2012 ◽  
Vol 201-202 ◽  
pp. 388-391
Author(s):  
Zi Qin Chen ◽  
Xiang Dong Gao
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
Weld Pool ◽  
High Power ◽  
High Speed ◽  
Welding Process ◽  
304 Stainless Steel ◽  
Fiber Laser Welding ◽  
Weld Pool Width ◽  
Laser Welding Process

In a high-power fiber laser welding process, the thermal radiation of a weld pool contains plenty of information for welding quality, in which the pool width can reflect the welding stability. Thus, extracting the welding pool width of high-power fiber laser welding based on infrared thermal imaging is an important method for monitoring the weld seam quality. In this paper, we studied the 304 stainless steel welded by a 10kW high-power fiber laser continuously. A near-infrared high-speed sensing camera was used to capture the weld pool images. Image algorithms such as median filtering, gray scale stretching, cutting, dynamic threshold mathematical morphology were applied to extract the weld pool image edge, analyze and detect the weld pool width. Welding experimental results showed that the proposed methods could extract the weld pool width, which could reflect the stability status of high-power fiber laser welding process accurately.

scholarly journals Mechanisms for Improvement of Weld Appearance in Autogenous Fiber Laser Welding of Thick Stainless Steels

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 625 ◽  
Author(s):  
Mingjun Zhang ◽  
Shun Chen ◽  
Yingzhe Zhang ◽  
Genyu Chen ◽  
Zhuming Bi
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
High Speed ◽  
Imaging System ◽  
Metal Flow ◽  
Welding Process ◽  
Back Surface ◽  
Fiber Laser Welding ◽  
Vapor Plume

High-power fiber laser welding is an efficient and effective way to produce heavy section structures. However, there is a significant challenge in producing the welds with free of imperfections such as nail-head-shaped welds, spatters, and root sagging. This is partially due to a lack of understanding of the welding mechanism of high-power fiber laser. In this paper, we were especially interested in the mechanism to improve the appearance of welds, and we focused on the autogenous laser welding on thick stainless steel plates by a 10 kW fiber laser. To look into the relations of process parameters and the quality of welds, a high-speed imaging system was applied to observe the molten pool flow and vapor plume during the welding process. The appearances of welds subjected to different welding conditions were analyzed. The results showed that (1) nail-head-shaped welds were suppressed by using a gas jet during laser welding process. (2) In the forward welding, a gentle upwelling molten metal flow on the rear keyhole wall, a deeper weld pool and a weaker vapor plume resulted in no spatter. (3) The gravity affected the formation of underfills and root sagging significantly during autogenous laser welding of thick plates. (4) When the workpiece was placed vertically in the transverse position, the welding process was stable without an aggregation of molten melt at the back surface. Moreover, the mechanisms of forming root sagging and humps were different at the top surface.

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

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.

Extraction of Molten Pool and Keyhole Characteristics during High Power Fiber Laser Welding

2012 ◽  
Vol 532-533 ◽  
pp. 344-347
Author(s):  
Ren He Zhen ◽  
Xiang Dong Gao
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
Molten Pool ◽  
Critical Role ◽  
Welding Process ◽  
Fiber Laser Welding ◽  
Inspection Method ◽  
Weld Pool Geometry ◽  
Laser Welding Process

It is well known that weld pool geometry plays a critical role in laser welding. In this study, an IPG YLR-10000 device was used to capture a series of molten pool images during high power fiber laser welding process. Then an extraction method of the geometric characteristics of these images was developed. This method could be applied to monitor the configuration of a molten pool and keyhole which was related to welding quality. The experimental results showed that this method was a reliable inspection method for monitoring the configuration of molten pool during high power fiber laser welding.

Fiber Laser Welding of Noncombustible Magnesium Alloy

2008 ◽  
Vol 580-582 ◽  
pp. 479-482 ◽  
Author(s):  
Yuji Sakai ◽  
Kazuhiro Nakata ◽  
Takuya Tsumura ◽  
Mitsuji Ueda ◽  
Tomoyuki Ueyama ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Magnesium Alloy ◽  
Laser Welding ◽  
Fiber Laser ◽  
Vickers Hardness ◽  
Laser Power ◽  
Welded Joint ◽  
Welding Process ◽  
Fiber Laser Welding ◽  
Laser Welding Process

Noncombustible magnesium alloy AMC602 (Mg-6mass%Al-2mass%Ca) extruded sheet of 2.0mm thickness was successfully welded using a fiber laser welding process at welding speed of 10m/min at 3kW laser power. Tensile strength of the welded joint was about 82 to 88% of that of the base metal. Vickers hardness, tensile strength and micro structural properties are also discussed.

Study of Plume Behavior during High-Power Disk Laser Welding

2012 ◽  
Vol 201-202 ◽  
pp. 1076-1079
Author(s):  
De Yong You ◽  
Xiang Dong Gao
Keyword(s):  
Laser Welding ◽  
High Power ◽  
High Speed ◽  
Welding Process ◽  
Image Sequences ◽  
Process Conditions ◽  
High Speed Photography ◽  
Disk Laser ◽  
Industrial Manufacturing ◽  
Laser Welding Process

Laser welding process has been widely used in industrial manufacturing. The purpose of this paper is to explore the inter-relation between laser welding results and the laser-induced plume behavior. High-power disk laser welding of stainless steel type304 was performed at different welding speeds. Combing the high speed camera and ultraviolet sensing filter, the plume image sequences of laser welding process have been obtained. Plume features including plume volume and plume flowing direction have been extracted by using high-speed photography and image processing technology. The dynamic behavior of laser-induced plume was investigated. The results showed that the laser-induced plume feature, especially the plume volume, was closely related to laser welding process conditions.

Effect of Laser-Induced Plume on Welding Process During High Power Fiber Laser Welding

2014 ◽  
Vol 41 (6) ◽  
pp. 0603005 ◽  
Author(s):  
邹江林 Zou Jianglin ◽  
李飞 Li Fei ◽  
牛建强 Niu Jianqiang ◽  
孔晓芳 Kong Xiaofang ◽  
马然 Ma Ran ◽  
...  
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
Welding Process ◽  
Fiber Laser Welding

scholarly journals High-Speed Observation and Spectroscopic Analysis of Laser-Induced Plume in High-Power Fiber Laser Welding of Stainless Steel

2007 ◽  
Vol 25 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Yousuke KAWAHITO ◽  
Keisuke KINOSHITA ◽  
Naoyuki MATSUMOTO ◽  
Masami MIZUTANI ◽  
Seiji KATAYAMA
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
High Speed ◽  
Spectroscopic Analysis ◽  
Fiber Laser Welding

Extraction of Characteristic Parameters of Keyhole during High Power Fiber Laser Welding

2012 ◽  
Vol 201-202 ◽  
pp. 352-355
Author(s):  
Yong Hua Liu ◽  
Xiang Dong Gao
Keyword(s):  
Laser Welding ◽  
Fiber Laser ◽  
High Power ◽  
Continuous Wave ◽  
Welding Process ◽  
Detection Methods ◽  
Deep Penetration ◽  
Welding Quality ◽  
Characteristic Parameters ◽  
Fiber Laser Welding

During deep penetration laser welding, a keyhole is formed in the molten pool. The characteristics of keyhole are related to the welding quality and stability. Analyzing the characteristic parameters of a keyhole during high power fiber laser welding is one of effective measures to control the welding quality and improve the welding stability. This paper studies a fiber laser butt-joint welding of Type 304 austenitic stainless steel plate with a high power 10 kW continuous wave fiber laser, and an infrared sensitive high-speed video camera was used to capture the dynamic images of the molten pools. A combination filtering system with a filter length of 960-990nm in front of the vision sensor was used to obtain the near infrared image and eliminate other light disturbances. The width, the area, the leftmost point, the rightmost point, the upmost point and the bottommost point of a keyhole were defined as the keyhole characteristic parameters. By using the image preprocessing method, such as median filtering, Wiener filtering, threshold segmentation and Canny edge detection methods, the characteristic parameters of a keyhole were obtained. By analyzing the change of the keyhole characteristic parameters during welding process, it was found that these parameters could reflect the quality and stability of laser welding effectively.

Optimization of Fiber Laser Welding Process Viarables and Performance Prediction Based on BP Neural Network

Applied laser ◽  
2010 ◽  
Vol 30 (6) ◽  
pp. 479-482
Author(s):  
郭亮 Guo Liang ◽  
王少华 Wang Shaohua ◽  
张庆茂 Zhang Qingmao ◽  
徐鹏嵩 Xu Pengsong ◽  
庞振华 Pang Zhenhua
Keyword(s):  
Neural Network ◽  
Laser Welding ◽  
Fiber Laser ◽  
Performance Prediction ◽  
Bp Neural Network ◽  
Welding Process ◽  
Fiber Laser Welding ◽  
And Performance ◽  
Laser Welding Process
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