Analysis of laser welding keyhole characteristics based on near-infrared high speed camera and X-ray sensing

In this paper, the keyhole of YAG laser welding 5A90 Al-Li alloy was observed and measured through the high speed camera. The characteristics of the keyhole and the effects of welding parameters were studied. The characteristics of the absorption of laser energy and the susceptivity for heat input in welding 5A90 were given. The results show that in this welding condition, the keyhole of laser welding 5A90 is nearly a taper and the highest temperature area is in the bottom. There are clear effects of heat input on the characteristics, especially the surface radius of keyhole and plasma/vapor in keyhole. Another phenomena is observed that sometime plasma/vapor could disappear in 0.3ms welding time, and this feature will be more remarkable as decrease of heat input. It shows that the absorption of energy is unsteady. It is known that when this instability reaches a certain value, an unsteady weld will be formed.

Download Full-text

Laser Processing of Asteroid Simulants

10.5194/epsc2020-860 ◽

2020 ◽

Author(s):

Niklas Anthony ◽

Mikael Granvik ◽

Christina Wanhainen ◽

Jan Frostevarg ◽

Heikki Suhonen ◽

...

Keyword(s):

Energy Efficient ◽

Laser Processing ◽

High Speed ◽

The Other ◽

High Speed Camera ◽

X Ray ◽

Nd:Yag Lasers ◽

Micro Tomography ◽

Power Densities ◽

Shed Light

<p>Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used pulsed Nd:YAG lasers on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10~000~frames~per~second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material. We wil also present some preliminary results of the effects of spallation of these materials.</p>

Download Full-text

Large Area Divertor Temperature Measurements Using A High-speed Camera With Near-infrared FiIters in NSTX

10.2172/1010973 ◽

2011 ◽

Author(s):

B C Lyons ◽

S J Zweben ◽

T K Gray ◽

J Hosea ◽

R Kaita ◽

...

Keyword(s):

High Speed ◽

Near Infrared ◽

Temperature Measurements ◽

High Speed Camera ◽

Large Area

Download Full-text

High-Speed X-Ray Transmission and Numerical Study of Melt Flows inside the Molten Pool during Laser Welding of Aluminum Alloy

Mathematical Problems in Engineering ◽

10.1155/2016/1409872 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Jin Peng ◽

Liqun Li ◽

Shangyang Lin ◽

Furong Zhang ◽

Qinglong Pan ◽

...

Keyword(s):

Aluminum Alloy ◽

Laser Welding ◽

Welding Speed ◽

Molten Pool ◽

High Speed ◽

Numerical Study ◽

Flow Behavior ◽

Front Wall ◽

X Ray ◽

Rear Part

By using the X-ray transmission imaging system, melt flows inside a molten pool were studied during laser welding of aluminum alloy at different welding speeds. Then, the correlation between temperature gradients along the direction of weld penetration and melt flows in the rear part of a molten pool was analyzed by using a three-dimensional numerical method. And the presented model was verified by experimental results. The corresponding investigation was carried out to further study the correlation between temperature gradient and melt flow behavior of the molten pool in the plate heated by preheating temperature. The results indicated that, in the rear part of the molten pool, the maximum flow velocity was located at the bottom of the molten pool. The melt metal in the rear molten pool caused by different welding speeds had significantly different flow trends. As the welding speed increased, the absorbed intensity on the keyhole front wall also increased as well as the recoil pressure that could maintain the keyhole opened. Consequently, the increase of the welding speed was more beneficial to improving the stability of the molten pool.

Download Full-text

MATLAB Image Treatment of Copper-Steel Laser Welding

Advances in Materials Science and Engineering ◽

10.1155/2020/8914841 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Massaud Mostafa ◽

J. Laifi ◽

M. Ashari ◽

Z.A. Alrowaili

Keyword(s):

Confidence Interval ◽

Laser Welding ◽

High Speed ◽

Pure Copper ◽

Copper Plate ◽

High Speed Camera ◽

Laser Parameters ◽

Melted Zone ◽

Laser Keyhole Welding ◽

Dissimilar Laser Welding

Continuous Yb:YAG laser keyhole welding of the pure copper plate to steel 316L sheet is performed for different laser parameters. The laser-generated welding keyhole and weld melted zone are observed by a high-speed camera. The image is treated by MATLAB and simple code is built to calculate the keyhole and melted zone area. This treatment is validated by the actual welding measurements, and the accuracy of the measurements is tested by the confidence interval law. The images obtained of keyhole and melt zone area in dissimilar laser welding are treated and analyzed to study the effect of changing the laser parameters.

Download Full-text

High-Speed X-Ray Analysis of Spatter Formation in Laser Welding of Copper

Physics Procedia ◽

10.1016/j.phpro.2013.03.058 ◽

2013 ◽

Vol 41 ◽

pp. 112-118 ◽

Cited By ~ 58

Author(s):

A. Heider ◽

J. Sollinger ◽

F. Abt ◽

M. Boley ◽

R. Weber ◽

...

Keyword(s):

Laser Welding ◽

High Speed ◽

X Ray

Download Full-text

High-speed x-ray imaging system for the investigation of laser welding processes

Journal of Laser Applications ◽

10.2351/1.5110595 ◽

2019 ◽

Vol 31 (4) ◽

pp. 042004 ◽

Cited By ~ 4

Author(s):

Meiko Boley ◽

Florian Fetzer ◽

Rudolf Weber ◽

Thomas Graf

Keyword(s):

Laser Welding ◽

High Speed ◽

Imaging System ◽

X Ray ◽

X Ray Imaging ◽

Welding Processes

Download Full-text

Weld Seam Deviation Detection Base on Laser Welding Pool’s Centroid

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.2594 ◽

2013 ◽

Vol 690-693 ◽

pp. 2594-2597

Author(s):

Ren He Zhen

Keyword(s):

Laser Welding ◽

High Speed ◽

Near Infrared ◽

Weld Seam ◽

Welding Process ◽

Infrared Camera ◽

Fiber Laser Welding ◽

Welding Pool ◽

Welding Equipment ◽

Set Up

For detecting weld seams deviation during the industrial actual welding process, IPG YLR-10000 high power fiber laser welding equipment was used during laser welding experiments. A high-speed near-infrared camera was used to capture the dynamic welding pool image sequences. Through studying the change of the features of near-infrared images of the weld pool when the laser beam deviated the weld seam, the centroid of the welding pool could be used as the deviated parameter of the weld seam. The welding pool images coordinates were established, and the ways of rotating and shifting the coordinates were used to build a model to test the welding spots deviation. Finally, the model of the relationship of the actual weld seam deviation and the tested weld seam deviation had been set up by using the regression analysis method. Its validity and feasibility had been tested by analyzing the models correlation R parameters.

Download Full-text

Scanning x-ray fluorescence microscopy and principal component analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133394 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1752-1753

Author(s):

Brian Cross

Keyword(s):

Principal Component Analysis ◽

Fluorescence Microscopy ◽

Spatial Resolution ◽

High Speed ◽

Image Acquisition ◽

Principal Component ◽

Fluorescence Microscope ◽

Acquisition Rate ◽

X Ray ◽

Speed Up

A relatively new entry, in the field of microscopy, is the Scanning X-Ray Fluorescence Microscope (SXRFM). Using this type of instrument (e.g. Kevex Omicron X-ray Microprobe), one can obtain multiple elemental x-ray images, from the analysis of materials which show heterogeneity. The SXRFM obtains images by collimating an x-ray beam (e.g. 100 μm diameter), and then scanning the sample with a high-speed x-y stage. To speed up the image acquisition, data is acquired "on-the-fly" by slew-scanning the stage along the x-axis, like a TV or SEM scan. To reduce the overhead from "fly-back," the images can be acquired by bi-directional scanning of the x-axis. This results in very little overhead with the re-positioning of the sample stage. The image acquisition rate is dominated by the x-ray acquisition rate. Therefore, the total x-ray image acquisition rate, using the SXRFM, is very comparable to an SEM. Although the x-ray spatial resolution of the SXRFM is worse than an SEM (say 100 vs. 2 μm), there are several other advantages.

Download Full-text

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152252 ◽

1989 ◽

Vol 47 ◽

pp. 56-57

Author(s):

Marc H. Peeters ◽

Max T. Otten

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

High Speed ◽

High Performance ◽

Functional Integration ◽

Energy Dispersive ◽

X Rays ◽

X Ray ◽

High Speed Analysis ◽

Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

Download Full-text