Segmentation of Molten Pool Infrared Images Using Morphology during High Power Disk Laser Welding

2012 ◽  
Vol 201-202 ◽  
pp. 91-94
Author(s):  
Yan Xi Zhang ◽  
Xiang Dong Gao
Keyword(s):  
Laser Welding ◽  
High Power ◽  
Molten Pool ◽  
Welding Process ◽  
Histogram Equalization ◽  
Welding Quality ◽  
Infrared Images ◽  
Traditional Methods ◽  
Disk Laser ◽  
Laser Welding Process

Configuration of a molten pool is related to the laser welding quality. Analyzing the configuration of a molten pool is important to monitor the laser welding process. This paper proposes a method of segmentation of a molten pool and its shadow during high power disk laser welding, consequently provides the groundwork for reconstruction of the molten pool and analysis of welding quality. Subsection linear stretching histogram equalization was applied to enhance the contrast of the original images firstly, and then edge detection was used to highlight the edges. After that we used the morphology filtering method to produce the segmentation mask, and then combined the mask with the original images to get the final segmentation results. Also, the proposed method was compared with other traditional methods. The experimental results showed that our method not only could give better segmentation results and process large quantities images automatically, but also overcame the less-segmentation problems of traditional methods.

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.

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.

Welding characteristics of S45C medium carbon steel in laser welding process using a high power CW Nd:YAG laser

2004 ◽  
Vol 39 (19) ◽  
pp. 6117-6119 ◽  
Author(s):  
Young-Tae Yoo ◽  
Dong-Gyu Ahn ◽  
Kung-Bo Ro ◽  
Seong-Wook Song ◽  
Ho-Jun Shin ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Laser Welding ◽  
High Power ◽  
Nd:Yag Laser ◽  
Welding Process ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Laser Welding Process

Numerical simulation of molten pool dynamics in high power disk laser welding

2012 ◽  
Vol 212 (1) ◽  
pp. 262-275 ◽  
Author(s):  
Won-Ik Cho ◽  
Suck-Joo Na ◽  
Claus Thomy ◽  
Frank Vollertsen
Keyword(s):  
Numerical Simulation ◽  
Laser Welding ◽  
High Power ◽  
Molten Pool ◽  
Disk Laser

Intense X-Ray Measurement of Transient Hydraulic Phenomena in Molten Pool During Laser Welding Process

2012 ◽  
Author(s):  
Tomonori Yamada ◽  
Takahisa Shobu ◽  
Susumu Yamashita ◽  
Takemitsu Ogawa ◽  
Kenta Sugihara ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Laser Welding ◽  
Phase Change ◽  
Molten Pool ◽  
Welding Process ◽  
In Situ Observation ◽  
Interface Shape ◽  
X Ray ◽  
Laser Welding Process

Spatial temperature distribution during the laser welding process has a huge effect on any residual stress distribution. Therefore, understanding of the transient hydraulic phenomena which affect the temperature distribution in the molten pool is very important. In this work, intense X-ray measurement at the Super Photon ring-8 GeV (SPring-8) facility well carried out to document the transient hydraulic phenomena in the molten pool during the laser welding process. Based on in-situ observation of inside material, the experimental results confirmed that the molten pool shapes, hydraulic condition such as flow velocity, etc.. In the case of laser power is 330W and spot diameter is 1mm, we observed the steady flow which consisted of downward flow and upward flow. The flow velocities were about 19.5 mm/s and 9.0 mm/s, respectively. Moreover, the rate of phase change was obtained from molten pool shape during laser welding. The rate of phase change was not constant during laser welding. Thus the interface shape might change at all time. Therefore, to evaluate the temperature distribution, it is necessary to consider not only convection but also the interface shape. These results indicate that the intense X-ray measurement during laser welding is very effective for the understanding the molten pool phenomena.

Development of high power laser welding process for pipe

1996 ◽  
Author(s):  
Tomotaka Hayashi ◽  
Yoji Inaba ◽  
Yosiyuki Matuhiro ◽  
Tateo Yamada ◽  
Takeo Kudo ◽  
...  
Keyword(s):  
Laser Welding ◽  
High Power ◽  
Welding Process ◽  
High Power Laser ◽  
Power Laser ◽  
Laser Welding Process

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.

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