scholarly journals High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation

2021 ◽  
Vol 5 (4) ◽  
pp. 127
Author(s):  
Marc Hummel ◽  
André Häusler ◽  
Arnold Gillner
Keyword(s):  
Stainless Steel ◽  
Laser Beam ◽  
Penetration Depth ◽  
Near Infrared ◽  
Welding Process ◽  
Modulation Method ◽  
Material Surface ◽  
Infrared Range ◽  
Weld Penetration ◽  
Power Modulation

For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the linear feed motion with an oscillating motion. This modulation method serves to widen the cross-section of the weld seam as well as to increase the process stability. Temporal power modulation refers to the controlled modulation of the laser power over time during the welding process. In this paper, the superposition of both temporal and spatial power modulation methods is presented, which enables a variable control of the weld penetration depth. Three weld geometries transverse to the feed direction are part of this investigation: the compensation of the weld penetration depth due to the asymmetric path movement during spatial power modulation only, a W-shaped weld profile, and a V-shaped. The weld geometries are investigated by the bed on plate weld tests with CuSn6. Furthermore, the use of combined power modulation for welding tests in butt joint configuration between CuSn6 and stainless steel 1.4301 with different material properties is investigated. The study shows the possibility of precise control of the welding depth by this methodology. Depending on the material combination, the desired regions with maximum and minimum welding depth can be achieved by the control of local and temporal power modulation on the material surface.

scholarly journals Spectroscopic closed loop control of penetration depth in laser beam welding process

2012 ◽  
Author(s):  
Teresa Sibillano ◽  
Antonio Ancona ◽  
Domenico Rizzi ◽  
Francesco Mezzapesa ◽  
Ali Riza Konuk ◽  
...  
Keyword(s):  
Laser Beam ◽  
Penetration Depth ◽  
Closed Loop ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Closed Loop Control ◽  
Loop Control

Laser Welding Simulations of Stainless Steel Joints Using Finite Element Analysis

2011 ◽  
Vol 383-390 ◽  
pp. 6225-6230
Author(s):  
K.R. Balasubramanian ◽  
T. Suthakar ◽  
K. Sankaranarayanasamy ◽  
G. Buvanashekaran
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Beam ◽  
Laser Welding ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Weld Bead ◽  
Heat Of Fusion ◽  
T Joints ◽  
Finite Element Software

Laser beam welding (LBW) is a fusion joining process that uses the energy from a laser beam to melt and subsequently crystallize a metal, resulting in a bond between parts. In this study, finite element method (FEM) is used for predicting the weld bead profile of laser welding butt, lap and T-joints. A three-dimensional finite element model is used to analyze the temperature distribution weld bead shape for different weld configurations produced by the laser welding process. In the model temperature-dependent thermo physical properties of AISI304 stainless steel, effect of latent heat of fusion and convective and radiative boundary conditions are incorporated. The heat input to the FEM model is assumed to be a 3D conical Gaussian heat source. The finite element software SYSWELD is employed to obtain the numerical results. The computed weld bead profiles for butt, lap and T-joints are compared with the experimental profiles and are found to be in agreement.

scholarly journals CHARACTERIZATION OF PHOTODIODES FOR DETECTION OF VARIATIONS IN PART-TO-PART GAP AND WELD PENETRATION DEPTH DURING REMOTE LASER WELDING OF COPPER-TO-STEEL BATTERY TAB CONNECTORS

2021 ◽  
pp. 1-34
Author(s):  
Giovanni Chianese ◽  
Pasquale Franciosa ◽  
Jonas Nolte ◽  
Dariusz Ceglarek ◽  
Stanislao Patalano
Keyword(s):  
Laser Welding ◽  
Penetration Depth ◽  
Energy Intensity ◽  
Low Cost ◽  
Welding Process ◽  
Thin Foil ◽  
Supervised Machine Learning ◽  
Weld Penetration ◽  
Thin Foils ◽  
Remote Laser Welding

Abstract This paper addresses sensor characterization to detect variations in part-to-part gap and weld penetration depth using photodiode-based signals during Remote Laser Welding (RLW) of battery tab connectors. Photodiode-based monitoring has been implemented largely for structural welds due to its relatively low cost and ease of automation. However, research in sensor characterization, monitoring and diagnosis of weld defects during joining of battery tab connectors is at an infancy and results are inconclusive. Motivated by the high variability during the welding process of dissimilar metallic thin foils, this paper aims to characterize the signals generated by a photodiode-based sensor to determine whether variations in weld quality can be isolated and diagnosed. Photodiode-based signals were collected during RLW of copper-to-steel thin-foil lap joint (Ni-plated copper 300 μm to Ni-plated steel 300 μm). The presented methodology is based on the evaluation of the energy intensity and scatter level of the signals. The energy intensity gives information about the amount of radiation emitted during the welding process, and the scatter level is associated with the accumulated and un-controlled variations. Findings indicated that part-to-part gap variations can be diagnosed by observing the step-change in the plasma signal, with no significant contribution given by the back-reflection. Results further suggested that over-penetration corresponds to significant increment of the scatter level in the sensor signals. Opportunities for automatic isolation and diagnosis of defective welds based on supervised machine learning are discussed.

Solid state red biphotonic excited emission from small dipolar fluorophores

2016 ◽  
Vol 4 (4) ◽  
pp. 766-779 ◽  
Author(s):  
Martin Ipuy ◽  
Yuan-Yuan Liao ◽  
Erwann Jeanneau ◽  
Patrice L. Baldeck ◽  
Yann Bretonnière ◽  
...  
Keyword(s):  
Solid State ◽  
Penetration Depth ◽  
Near Infrared ◽  
Emission Wavelength ◽  
Infrared Range ◽  
Two Photon ◽  
Photon Excitation ◽  
Near Infrared Range ◽  
Two Photon Excitation

Dyes emitting in the solid state in the red or near-infrared range are much sought after for application in bioimaging especially if the long emission wavelength can be combined with two-photon excitation to provide unique contrast and penetration depth.

Effects of Phase Matching Pattern on Pulse Laser-Arc Hybrid Welding Process

2014 ◽  
Vol 633-634 ◽  
pp. 634-637
Author(s):  
Li Ming Liu ◽  
Chao Song ◽  
Qiu Ping Song ◽  
Gang Song
Keyword(s):  
Penetration Depth ◽  
Pulse Laser ◽  
Arc Welding ◽  
Welding Process ◽  
Welding Current ◽  
Phase Matching ◽  
Weld Penetration ◽  
Current Waveform ◽  
Weld Formation ◽  
Hybrid Plasma

This paper proposed a method on accurate phase matching control between the pulse laser and the AC TIG arc in real time, and a pulse laser-arc hybrid heat source phase matching control system is developed as well. With the utilization of this system in two typical matching cases that the pulse laser acts on the peak and the trough of the arc welding current waveform, effect regulations on weld formation, weld penetration depth and hybrid plasma shape are studied during welding on magnesium alloy AZ61. Results indicate that, when the pulse laser acting on the peak of arc welding current waveform, the weld formation is better than that of on the trough. However, when pulse laser act on the arc trough the weld penetration depth is deeper than that of on the peak.

Real-Time Weld Penetration Depth Monitoring With Laser Ultrasonic Sensing System

2005 ◽  
Vol 128 (1) ◽  
pp. 280-286 ◽  
Author(s):  
Bao Mi ◽  
Charles Ume
Keyword(s):  
Real Time ◽  
Penetration Depth ◽  
Weld Pool ◽  
Phased Array ◽  
Welding Process ◽  
Analytical Relationship ◽  
Correlation Technique ◽  
Weld Penetration ◽  
Weld Quality ◽  
Sensing System

A real-time ultrasound-based system for controlling robotic weld quality by monitoring the weld pool is presented. The weld penetration depth is one of the most important geometric parameters that define weld quality, hence, remains a key control quantity. The sensing system is based on using a laser phased array technique to generate focused and steered ultrasound, and an electromagnetic acoustic transducer (EMAT) as a receiver. When a pulsed laser beam is incident on the surface of a condensed matter, either the thermoelastic expansion or ablation induces mechanical vibrations that propagate as ultrasound within the specimen. Both the ultrasound generation by the laser phased array and the reception by the EMAT are noncontact, which eliminates the need for a couplant medium. They are capable of operating at high temperatures involved in the welding process. The ultrasound generated by the laser phased array propagates through the weld pool and is picked up by the EMAT receiver. A signal-processing algorithm based on a cross-correlation technique has been developed to estimate the time-of-flight (TOF) of the ultrasound. The relationship between the TOF and the penetration depth of the weld has been established experimentally and analytically. The analytical relationship between the TOF and the penetration depth, which is obtained by the ray-tracing algorithm and geometric analysis, agrees well with the experimental measurements.

Photodiode-Based In-Process Monitoring of Part-to-Part Gap and Weld Penetration Depth in Remote Laser Welding of Copper-to-Steel Battery Tab Connectors

2021 ◽  
Author(s):  
Giovanni Chianese ◽  
Pasquale Franciosa ◽  
Jonas Nolte ◽  
Darek Ceglarek ◽  
Stanislao Patalano
Keyword(s):  
Laser Welding ◽  
Penetration Depth ◽  
Process Monitoring ◽  
Energy Intensity ◽  
Welding Process ◽  
Supervised Machine Learning ◽  
Dissimilar Metals ◽  
Weld Penetration ◽  
Thin Foils ◽  
Remote Laser Welding

Abstract This paper addresses in-process monitoring of part-to-part gap and weld penetration depth using photodiode-based signals during Remote Laser Welding (RLW) of battery tab connectors. Photodiode-based monitoring has been largely implemented for structural welds due to its relatively low cost and ease of automation. However, the application of photodiode-based monitoring to RLW of thin foils of dissimilar metals for battery tab connectors remains an unexplored area of research and will be addressed in this paper. Motivated by the high variability during the welding process of thin foils of dissimilar metals, this paper aims to evaluate the photodiode-based signals to determine if variations in weld quality can be isolated and diagnosed. The main focus is in diagnosing defective weld conditions caused by part-to-part gap variations and/or excessive weld penetration depth. Photodiode-based signals have been collected during RLW of copper-to-steel thin foils lap joint (Ni-plated copper 300 μm to Ni-plated steel 300 μm). The methodology is based on the evaluation of the energy intensity and scatter level of the signals. The energy intensity gives information about the amount of radiation emitted during the welding process, and the scatter level is associated to the accumulated and un-controlled variations. Findings indicated that part-to-part gap variations can be diagnosed by observing the step-change in the plasma signal, with no significant contribution given by the back-reflection. Results further suggested that over-penetration corresponds to significant increment of the scatter level in the sensor signals. Opportunities for automatic isolation and diagnosis of defective welds based on supervised machine learning will be discussed throughout the paper.

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