Laser weld penetration improvement by laser activation process with oxygen

2007 ◽  
Author(s):  
Masami Mizutani ◽  
Seiji Katayama
Keyword(s):  
Activation Process ◽  
Weld Penetration ◽  
Laser Weld

Monitoring of laser weld penetration using sensor fusion

2002 ◽  
Vol 14 (2) ◽  
pp. 114-121 ◽  
Author(s):  
Allen Sun ◽  
Elijah Kannatey-Asibu ◽  
Mark Gartner
Keyword(s):  
Sensor Fusion ◽  
Weld Penetration ◽  
Laser Weld

Estimation of Al/Cu laser weld penetration in photodiode signals using deep neural network classification

2021 ◽  
Vol 33 (4) ◽  
pp. 042009
Author(s):  
Kidong Lee ◽  
Sanghoon Kang ◽  
Minjung Kang ◽  
Sung Yi ◽  
Cheolhee Kim
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Weld Penetration ◽  
Laser Weld ◽  
Neural Network Classification

scholarly journals Laser Weld Penetration Estimation Using Temperature Measurements

1999 ◽  
Vol 121 (2) ◽  
pp. 179-188 ◽  
Author(s):  
K. N. Lankalapalli ◽  
J. F. Tu ◽  
K. H. Leong ◽  
M. Gartner
Keyword(s):  
Penetration Depth ◽  
Plate Thickness ◽  
Bottom Surface ◽  
Process Conditions ◽  
Measured Signal ◽  
Weld Penetration ◽  
Laser Weld ◽  
Low Carbon ◽  
Conduction Model ◽  
Bead Width

Penetration depth is an important factor critical to the quality of a laser weld. This paper presents a 3D heat conduction model with a moving line source to correlate the temperature measured on the bottom surface of the workpiece to the weld penetration, weld bead width and welding speed. Temperatures on the bottom surface of the workpiece are measured using infrared thermocouples located behind the laser beam. The averaging effect due to the temperature measurement spot size is analyzed. This paper provides a model-based approach for laser weld penetration monitoring instead of a pure empirical correlation between a measured signal (e.g., acoustic, infrared) and the penetration depth. Experiments were conducted to compare the depth estimation based on the model to bead-on-plate welds on low carbon steel plates of varying thickness at different laser power levels and speeds. It is shown that the temperature on the bottom surface is a consistent indicator of penetration depth and that the correlation is also sensitive to the sensor location as well as other process conditions such as weld shape, width, and the plate thickness. The proposed model is computationally efficient and is suitable for on-line process monitoring application.

On-Line Estimation of Laser Weld Penetration

1997 ◽  
Vol 119 (4) ◽  
pp. 791-801 ◽  
Author(s):  
Jay F. Tu ◽  
Kishore N. Lankalapalli ◽  
Mark Gartner ◽  
Keng H. Leong
Keyword(s):  
Penetration Depth ◽  
Finite Size ◽  
Depth Estimation ◽  
Process Models ◽  
Bottom Surface ◽  
Weld Penetration ◽  
Weld Quality ◽  
Laser Weld ◽  
Production Environment ◽  
On Line

High-power CO2 laser welding has been widely used in the industry because of its high productivity and excellent weld quality. In order to tap the potential of this process completely, it is important to have on-line weld quality inspection methods to improve the process productivity and reliability by achieving 100 percent weld inspection. Weld penetration is one of the most important factors critical to the quality of a laser weld. However, it is very difficult to directly measure the extent of penetration without sectioning the workpiece. In this paper a model-based penetration depth estimation technique suitable for the production environment is developed. The proposed model relates the temperature measured on the bottom surface of the workpiece, weld bead width, laser beam power and welding speed to penetration depth. The closed-loop depth estimator combines the model and a model-error compensator to compensate for the uncertainty in the measurement of the laser power and absorptivity. Other effects considered are the averaging due to the finite size of the sensor, delay based on the sensor location and the process and sensor dynamics. Several bead-on-plate and butt welds were made on low carbon steel plates to validate the static process models and the depth estimation scheme. Temperatures on the bottom surface of the workpiece during welding were measured using infrared thermocouples. The welds were sectioned longitudinally to obtain the penetration profile. The penetration profiles estimated by the depth estimator matched satisfactorily with the measured penetration profiles. The results validate the capability of the proposed depth estimator to estimate penetration depth and its ability to trace the dynamic changes in penetration depth.

Laser weld penetration monitoring with multiple emission signal measurements

1999 ◽  
Vol 11 (2) ◽  
pp. 47-53 ◽  
Author(s):  
D. F. Farson ◽  
A. Ali ◽  
X. C. Li
Keyword(s):  
Weld Penetration ◽  
Laser Weld ◽  
Emission Signal

scholarly journals Laser weld penetration estimation using temperature measurements

1997 ◽  
Author(s):  
K.N. Lankalapalli ◽  
J.F. Tu ◽  
K.H. Leong ◽  
M. Gartner
Keyword(s):  
Temperature Measurements ◽  
Weld Penetration ◽  
Laser Weld

Interpretation of Laser Weld Penetration and Welding Phenomena(Invited Paper)

2009 ◽  
Vol 36 (12) ◽  
pp. 3160-3166 ◽  
Author(s):  
Seiji Katayama Seiji Katayama* ◽  
Yousuke Kawahito Yousuke Kawahito
Keyword(s):  
Weld Penetration ◽  
Laser Weld

SEM and Auger microanalysis studies of Cu-Be dynode surfaces at each activation condition

1978 ◽  
Vol 36 (1) ◽  
pp. 524-525
Author(s):  
T. Koshikawa ◽  
Y. Fujii ◽  
E. Sugata ◽  
F. Kanematsu
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Life Time ◽  
Activation Process ◽  
Beam Diameter ◽  
Activation Temperature ◽  
Electron Multiplier ◽  
Activation Condition ◽  
Activation Conditions

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.

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