scholarly journals Laser Spot Micro-Welding of Ultra-Thin Steel Sheet

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 342
Author(s):  
Quanhong Li ◽  
Zhongyan Mu ◽  
Manlelan Luo ◽  
Anguo Huang ◽  
Shengyong Pang
Keyword(s):  
Laser Pulse ◽  
Solder Joint ◽  
Peak Power ◽  
Laser Energy ◽  
Stable State ◽  
Welding Process ◽  
Laser Spot ◽  
Evaporation Temperature ◽  
Thin Steel ◽  
Weld Depth

This paper reports a mechanism understanding how to reduce the solder joint failure phenomenon in the laser spot micro-welding process of ultra-thin steel sheets. An optimization method to improve solder joint service life is proposed. In this study, the time-dependent dynamic behaviors of the keyhole and the weld pool are simulated, and the temperatures in the keyhole of two different laser pulse waveforms are compared. The results show that laser energy attenuation mode (LEAM) can only obtain shallow weld depth because of the premature decay of the laser power of waveform, resulting in the laser beam that cannot be concentrated in the keyhole. The temperature inside the keyhole of LEAM fluctuates significantly, which shows a downward trend. Due to the existence of the peak power of waveform in laser energy continuous mode (LECM), the large angle of inclination of the wall of the keyhole inside the melt pool is more conducive to the multiple reflections of the laser beam in the keyhole and increases the absorption rate of the laser energy by the base material, resulting in the “keyhole effect”. But the temperature in the keyhole gradually rises, close to the evaporation temperature. A method combining LEAM and LECM to improve the solder joint service life by optimizing the temperature in the keyhole indirectly by adjusting the peak power of the laser pulse waveform is proposed in this study. The experimental results show that the weld depth can be optimized from 0.135 mm to 0.291 mm, and the tensile strength can be optimized from 88 MPa to 288 MPa. The bonding performance between the upper and lower plates is effectively improved. It can reach the required weld depth in a short time and improve the welding efficiency of the laser spot micro-welding process. The simulation results show that the temperature inside the keyhole is well optimized below the evaporation temperature of the material, which can avoid the violent evaporation of the welding process and keep the whole welding process in a stable state. By optimizing the laser pulse waveform, the temperature inside the keyhole can reach 3300 K, and it is always in a stable state than before optimization. The stable temperature inside the keyhole can help to reduce violent oscillation and spattering of the molten pool and improve welding efficiency and joint life. The research can help provide effective process guidance for the optimization of different laser pulse waveforms in the micro-welding process.

Effects of active flux on plasma behavior and weld shape in laser welding of X5CrNi189 stainless steel

2016 ◽  
Vol 30 (31) ◽  
pp. 1650375 ◽  
Author(s):  
Hongbin Dai ◽  
Jun Peng
Keyword(s):  
Stainless Steel ◽  
Laser Welding ◽  
Laser Plasma ◽  
Laser Energy ◽  
Weld Zone ◽  
Welding Process ◽  
Width Ratio ◽  
Weld Depth ◽  
Active Flux ◽  
Plasma Behavior

In this paper, stainless steel was welded by active flux-aided laser welding method. The effects of single active flux (Cr2O3, SiO2 and TiO2) and composite active flux on laser welding were studied. In the welding process, laser plasma behavior was recorded by a high-speed imaging system. The results show that, with the addition of active flux, the absorption of laser energy and melting efficiency increase. In the laser power of 750 W, effects of active flux on weld depth to width ratio are given by the order: composite active flux [Formula: see text] SiO[Formula: see text] Cr2O[Formula: see text] TiO2. The effect of composite active flux is the most significant and it can increase the weld depth to width ratio to 85%. Active flux can restrict the laser plasma. With the addition of composite active flux, the projected area of laser plasma obtained obviously reduced, and it can be reduced by 41.39%. Active flux cannot obviously change the main components in weld zone, but can change the grains of austenite and ferrite.

scholarly journals Dependence of laser accelerated protons on laser energy following the interaction of defocused, intense laser pulses with ultra-thin targets

2011 ◽  
Vol 29 (3) ◽  
pp. 345-351 ◽  
Author(s):  
C.M. Brenner ◽  
J.S. Green ◽  
A.P.L. Robinson ◽  
D.C. Carroll ◽  
B. Dromey ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Focal Spot ◽  
Laser Pulse Energy ◽  
Laser Energy ◽  
Spot Size ◽  
Proton Flux ◽  
Focal Spot Size ◽  
Order Of Magnitude ◽  
Laser Focal Spot ◽  
Accelerated Protons

AbstractThe scaling of the flux and maximum energy of laser-driven sheath-accelerated protons has been investigated as a function of laser pulse energy in the range of 15–380 mJ at intensities of 1016–1018 W/cm2. The pulse duration and target thickness were fixed at 40 fs and 25 nm, respectively, while the laser focal spot size and drive energy were varied. Our results indicate that while the maximum proton energy is dependent on the laser energy and laser spot diameter, the proton flux is primarily related to the laser pulse energy under the conditions studied here. Our measurements show that increasing the laser energy by an order of magnitude results in a more than 500-fold increase in the observed proton flux. Whereas, an order of magnitude increase in the laser intensity generated by decreasing the laser focal spot size, at constant laser energy, gives rise to less than a tenfold increase in observed proton flux.

Preparation ZnO nanoparticles with Different Concentration by Laser Ablation in Liquid

2021 ◽  
Vol 39 (1B) ◽  
pp. 197-202
Author(s):  
Ghufran S. Jaber ◽  
Khawla S. Khashan ◽  
Maha J. Abbas
Keyword(s):  
Particle Size ◽  
Laser Ablation ◽  
Laser Pulse ◽  
Laser Energy ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Pulse Number ◽  
Average Particle ◽  
Zno Nps ◽  
Laser Ablation In Liquid

The effects of varying laser pulse numbers on the fabricated of ZnONPs by pulsed laser ablation in deionized water of Zn-metal are investigated. The Nd: YAG laser at energy 600mJ prepared three samples by change the laser pulse number (100, 150, and 200). The results were collected and examined using an electron scanning microscope, XRD – diffraction, and transmission electron microscope. The result revealed the colloidal spherical shape and the homogeneous composition of the ZnO NPs. The nanoparticles resulted in different concentrations and sized distributions by changing the pulse number of a laser. The average particle size and the mass concentration of particle size increase with an increasing number of laser pulses by fixed the laser energy.

scholarly journals Understanding of BeCu Interaction Characteristics with a Variation of ns Laser-Pulse Duration

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1423 ◽  
Author(s):  
Dongkyoung Lee
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Pulse Energy ◽  
Laser Pulse Energy ◽  
Laser Spot ◽  
Main Body ◽  
Crater Size ◽  
Stamping Process ◽  
Cut Quality ◽  
Mechanical Cutting

An inspection process using a Spring Contact Probe (SCP) is an essential step in the semiconductor-manufacturing process. Many plungers, which are the main body of the SCP, are manufactured by a stamping process. After the stamping process, mechanical cutting is applied and the plunger body may be damaged. Thus, to improve cut quality and productivity while minimizing body damage, laser spot cutting can be used. To fully utilize this technology, it is necessary to investigate interaction characteristics of beryllium copper (BeCu) during laser spot cutting. Effects of a total irradiated laser-pulse energy (1 mJ ~1000 mJ ) and pulse duration (100 ns ~8 ns ) on the material-removal zone, thermal depth, and crater size are examined. The crater size can be affected by the localization of heating dominantly. An incubation model is applied to investigate the correlation between crater size and laser-pulse energy. Surface morphology characteristics such as edge separation, small particles, spatter motion, and soaring-up motion are observed.

scholarly journals Tunable, high peak power terahertz radiation from optical rectification of a short modulated laser pulse

2006 ◽  
Vol 14 (15) ◽  
pp. 6813 ◽  
Author(s):  
Daniel F. Gordon ◽  
Antonio Ting ◽  
Ilya Alexeev ◽  
Richard Fischer ◽  
Phillip Sprangle ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Terahertz Radiation ◽  
Peak Power ◽  
High Peak ◽  
Optical Rectification ◽  
High Peak Power

Study on Laser Welding of Phone Nuts

2013 ◽  
Vol 815 ◽  
pp. 778-781
Author(s):  
Xiao Hong Wu
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Laser Pulse ◽  
Laser Welding ◽  
Pulse Energy ◽  
Pulse Width ◽  
Peak Power ◽  
Laser Pulse Energy ◽  
304 Stainless Steel ◽  
Power Pulse

Used YAG pulse laser to weld 304 stainless steel nuts, studied about the parameters such as peak power, pulse width, defocus distance impacting on the performance of the joints welded by laser. The studies showed that the tensile strength and torque of the nuts increased as the peak power and the pulse width increased.Burn through in welding easy occur when laser pulse energy is too big, pulse width is too wide or defocus distance is too low.

Analysis and comparison of semiconductor materials processed at IR vs. UV laser wavelengths for DRAM yield enhancement applications

2005 ◽  
Vol 890 ◽  
Author(s):  
Andy E. Hooper ◽  
Allen Kawasaki ◽  
Paul Kirby ◽  
Robert Hainsey ◽  
Jeongho Bang ◽  
...  
Keyword(s):  
Laser Energy ◽  
Yield Enhancement ◽  
Laser Spot ◽  
Semiconductor Layer ◽  
Semiconductor Materials ◽  
Uv Laser ◽  
Spot Diameter ◽  
Materials Used ◽  
Laser Spot Diameter

ABSTRACTThis report demonstrates the effects of IR and UV laser energy on common semiconductor layer stack materials used for DRAM laser fuses. By moving from IR to UV wavelengths it is possible to significantly shrink the laser spot diameter from ∼1.6 μm to 0.8 μm. Effects and concerns for the absorption of UV energy by Si, SiO2, nitrides, and oxynitrides are also presented.

scholarly journals RESEARCH OF SEAM DIMENSIONAL DEPENDENCE ON THE SHORT-CIRCUIT CURRENT IN MMA WELDING PROCESS / SIŪLĖS MATMENŲ PRIKLAUSOMYBĖS NUO TRUMPOJO JUNGIMO SROVĖS STIPRIO TYRIMAS, VIRINANT GLAISTYTAISIAIS ELEKTRODAIS

2013 ◽  
Vol 5 (6) ◽  
pp. 659-663
Author(s):  
Mindaugas Rimkus ◽  
Ivanas Višniakas ◽  
Česlovas Kazakevičius
Keyword(s):  
Arc Welding ◽  
Drop Size ◽  
Short Circuit ◽  
Welding Process ◽  
Short Circuit Current ◽  
Mma Welding ◽  
Metal Drop ◽  
Dimensional Dependence ◽  
Ridge Height ◽  
Weld Depth

In this article the changes of seams properties of steel S235J2(LST EN 10025:2004) were analyzed, produced by welding withdifferent technology are discussed. Samples were welded byhand arc welding, using AV-23 and AV-66 welding electrodes.The welded seams were made by changing short-circuit current.The duration of weld depth, ridge height, metal drop size, metaldrop frequency, short-circuit time and short-circuit current valueare determinated.The results of the research are given in graphs,final conclusions are also written. Santrauka Straipsnyje tiriami mažaanglio plieno S235J2 (LST EN 10025:2004) virintinių siūlių matmenų pokyčiai, apvirinant plieną skirtingais glaistytaisiais elektrodais įvairiais suvirinimo režimais. Tyrimų metu buvo naudojami AV-23 ir AV-66 glaistytieji elektrodai ir keičiamas trumpojo jungimo srovės stipris. Nustatytas ryšys tarp metalo įvirinimo gylio, rumbelės aukščio, išlydytų lašų dydžio ir kiekio, trumpojo jungimo trukmės ir srovės dydžio. Gauti tyrimų rezultatai, nubraižyti priklausomybių grafikai ir pateiktos išvados.

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