Parametric Analysis of Laser Beam Percussion Drilling for Thin Titanium Alloy Sheet Using Yb: Yag Fiber Laser

2021 ◽  
pp. 1-24
Author(s):  
Mohit Singh ◽  
Sanjay Mishra ◽  
Vinod Yadava ◽  
J. Ramkumar
Keyword(s):  
Laser Beam ◽  
Fiber Laser ◽  
Pulse Width ◽  
Peak Power ◽  
Laser Pulses ◽  
Pulse Frequency ◽  
Alloy Sheet ◽  
Power Pulse ◽  
The Individual ◽  
Percussion Drilling

Laser beam percussion drilling (LBPD) can create high density holes in aerospace materials with the repeated application of laser pulses at a single spot. In this study, one-parameter-at-a-time approach has been used to investigate the individual effect of peak power, pulse width and pulse frequency on geometrical accuracy and metallurgical distortion during LBPD of 0.85[Formula: see text]mm thick Ti–6Al–4V sheet using 200[Formula: see text]W Yb:YAG fiber laser. It has been found that the output parameters behave differently at the higher and lower values of a particular input process. The increase of pulse width from 1 to 1.50[Formula: see text]ms increases hole taper by 20% whereas the same corresponding change from 1.50 to 2.00[Formula: see text]ms reduces the taper by 20%. The increase of pulse frequency from 10 to 50[Formula: see text]Hz reduces hole circularity by 40% but the same proportionate change from 50 to 90[Formula: see text]Hz reduces circularity by 79%. Increase of peak power from 1.70 to 2.0[Formula: see text]kW increases hole taper by 8% but the corresponding increase from 2 to 2.30[Formula: see text]kW is 143%.

Statistical modelling of laser percussion drilling for hole taper and circularity control

2002 ◽  
Vol 216 (3) ◽  
pp. 307-319 ◽  
Author(s):  
M Ghoreishi ◽  
D K Y Low ◽  
L Li
Keyword(s):  
Pulse Width ◽  
Peak Power ◽  
Statistical Modelling ◽  
Pulse Frequency ◽  
Hole Diameter ◽  
Complete Analysis ◽  
Yttrium Aluminium Garnet ◽  
Controllable Factors ◽  
Laser Percussion Drilling ◽  
Percussion Drilling

The aim of the present work is to investigate the effects of different variables and their interactions in laser percussion drilling and to understand the possibility of controlling simultaneously the two important characteristics of a laser drilled hole: taper and circularity. Six variables, namely the peak power, pulse width, pulse frequency, number of pulses, assist gas pressure and focal plane position, were selected as independent controllable factors. The response surface method was used to statistically analyse the process. For each variable, five levels were considered and the experiments were performed based on a central composite design. A fibre-optic delivered neodymium-doped yttrium aluminium garnet laser was used to laser percussion drill mild steel sheets with a thickness of 2.5mm. The entrance diameter, the taper and the ratio of maximum to minimum Feret diameter for the hole entrance (circularity) were considered as responses/outputs in order to evaluate the process performance in terms of hole taper and circularity. Statistical modelling was carried out to develop mathematical models to relate the responses (outputs) to the six independent variables through multiple regression. A complete analysis of variance (ANOVA) was performed to test the significance of the obtained coefficients at 1, 5 and 7 per cent levels of significance. The developed models were verified by experiments. The work has shown that the pulse width and peak power have significant effects on the hole diameter, hole taper and hole circularity. However, the pulse frequency has no effect on these three hole characteristics. The number of pulses has no significant effect on hole diameter and circularity but has a significant effect on hole taper.

The diffraction-ray model of single filamentation of femtosecond laser pulses for estimating characteristics of the multiple filamentation domain in air

2021 ◽  
Vol 64 (1) ◽  
pp. 154-164
Author(s):  
A.A. Zemlyanov ◽  
◽  
Y.E. Geints ◽  
O.V. Minina ◽  
◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Beam ◽  
Peak Power ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Small Scale ◽  
Beam Forming ◽  
Physical Processes ◽  
Multiple Filamentation ◽  
Number Increase

The characteristics of the domain of multiple filamentation of femtosecond laser pulses in air were estimated based on the single filamentation model. As the single filamentation model, the diffraction-ray model is considered. It is based on the representation of a laser beam as a set of diffraction-ray tubes nested in each other that do not intersect in space and do not exchange energy with each other. In this situation changes in tubes shape and cross section during propagation demonstrate the effect of physical processes that occur with radiation in the medium. It is shown that the use of this model for interpreting experimental results and predicting effects is effective. In particular, it was demonstrated that the radius of small-scale intensity inhomogeneities in the profile of a centimeter laser beam, forming the domain of multiple filamentation of subterawatt femtosecond laser pulses, is several millimeters. The power in these inhomogeneities varies from several units to several tens of gigawatts. Telescoping the initial laser beam, leading to an increase in its radius, also expands the sizes of the initial small-scale intensity inhomogeneities and reduces the power contained in them. As a result of this, the coordinate of the filamentation beginning shifts along the path from the source of laser pulses. As the peak power in the beam increases, the length of the filaments and their number increase.

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.

scholarly journals Graphene slurry based passive Q-switcher in erbium doped fiber laser

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Siti Nur Fatin Zuikafly ◽  
Nor Farhah Razak ◽  
Rizuan Mohd Rosnan ◽  
Sulaiman Wadi Harun ◽  
Fauzan Ahmad
Keyword(s):  
Pump Power ◽  
Fiber Laser ◽  
Pulse Width ◽  
Peak Power ◽  
Signal To Noise Ratio ◽  
Pulsed Laser ◽  
Laser Cavity ◽  
Signal To Noise ◽  
Maximum Pulse Energy ◽  
Erbium Doped

In this work, a Graphene slurry based passive Q-switcher fabricated from Graphene-Polylactic acid (PLA) filament which is used for 3D printing. To produce the Graphene slurry, the diameter of the filament was reduced and Tetrahydrofuran (THF) was used to dissolve the PLA. The Graphene-THF suspension was drop cast to the end of a fiber ferrule and the THF then evaporated to develop Graphene slurry based SA which is integrated in fiber laser cavity. At threshold input pump power of 30.45 mW, a Q-switched Erbium-doped fiber laser (EDFL) can be observed with the wavelength centered at 1531.01 nm and this remained stable up to a pump power of 179.5 mW. As the pump power was increased gradually, an increase in the repetition rates was recorded from 42 kHz to 125 kHz, while the pulse width was reduced to 2.58 μs from 6.74 μs. The Q-switched laser yielded a maximum pulse energy and peak power of 11.68 nJ and 4.16 mW, respectively. The proposed Graphene slurry based saturable absorber also produced a signal-to-noise ratio of 44 dB indicating a stable Q-switched pulsed laser.

scholarly journals 172  fs, 243  kW peak power pulse generation from a Ho-doped fiber laser system

2018 ◽  
Vol 43 (19) ◽  
pp. 4619 ◽  
Author(s):  
Mengmeng Wang ◽  
Hui Zhang ◽  
Rongling Wei ◽  
Zexiu Zhu ◽  
Shuangchen Ruan ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Peak Power ◽  
Laser System ◽  
Pulse Generation ◽  
Power Pulse

Acousto-Optic Q-Switched Pulse Fiber Laser with the Peak Power of 9kW

2013 ◽  
Vol 760-762 ◽  
pp. 125-128 ◽  
Author(s):  
Yong Liu ◽  
Lin Lin ◽  
Ji Wang ◽  
Kai Chen ◽  
Guo Zheng Wang ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Output Power ◽  
Repetition Rate ◽  
Pulse Width ◽  
Peak Power ◽  
Average Power ◽  
Repetition Frequency ◽  
Pulse Waveform ◽  
Pulse Output ◽  
The One

An acousto-optic Q-switched pulse fiber laser was presented, and the output power of 20.3W was obtained by using the one-stage Ytterbium-doped double-cladding fiber amplification. The repetition frequency of the pulse fiber laser was tunable in the range of 20-60kHz. We obtained the pulse output with pulse width of 113ns, peak power of 9kW and the average power of 20.3W, when the repetition frequency was 20kHz. We also measured pulse width at different repetition rate and analyzed pulse waveform.

Pulse width and peak power optimization in a mode-locked fiber laser with a semiconductor saturable absorber mirror

2012 ◽  
Vol 54 (10) ◽  
pp. 2256-2261 ◽  
Author(s):  
Seung Bum Cho ◽  
Hoseong Song ◽  
Sangyoun Gee ◽  
Chang-Soo Park ◽  
Dug Young Kim
Keyword(s):  
Fiber Laser ◽  
Saturable Absorber ◽  
Pulse Width ◽  
Peak Power ◽  
Power Optimization ◽  
Semiconductor Saturable Absorber

scholarly journals Passive Q-Switching by Cr4+:YAG Saturable Absorber of Buried Depressed-Cladding Waveguides Obtained in Nd-Doped Media by Femtosecond Laser Beam Writing

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1689 ◽  
Author(s):  
Gabriela (Salamu) ◽  
Nicolaie Pavel
Keyword(s):  
Femtosecond Laser ◽  
Laser Beam ◽  
Repetition Rate ◽  
Peak Power ◽  
Continuous Wave ◽  
Average Power ◽  
Laser Pulses ◽  
Direct Writing ◽  
Optical Efficiency ◽  
Femtosecond Laser Beam

We report on laser performances obtained in Q-switch mode operation from buried depressed-cladding waveguides of circular shape (100 μm diameter) that were inscribed in Nd:YAG and Nd:YVO4 media by direct writing with a femtosecond laser beam. The Q-switch operation was realized with a Cr4+:YAG saturable absorber, aiming to obtain laser pulses of moderate (few μJ) energy at high (tens to hundreds kHz) repetition rate. An average power of 0.52 W at 1.06 μm consisting of a train of pulses of 7.79 μJ energy at 67 kHz repetition rate, was obtained from a waveguide realized in a 4.8 mm long, 1.1-at % Nd:YAG ceramics; the pulse peak power reached 1.95 kW. A similar waveguide that was inscribed in a 3.4 mm long, 1.0-at % Nd:YVO4 crystal yielded laser pulses with 9.4 μJ energy at 83 kHz repetition rate (at 0.77 W average power) and 1.36 kW peak power. The laser performances obtained in continuous-wave operation were discussed for each waveguide used in the experiments. Thus, a continuous-wave output power of 1.45 W was obtained from the circular buried depressed-cladding waveguide inscribed in the 1.1-at %, 4.8 mm long Nd:YAG; the overall optical-to-optical efficiency, with respect to the absorbed pump power, was 0.21. The waveguide inscribed in the 1.0-at %, 3.4 mm long Nd:YVO4 crystal yielded 1.85 W power at 0.26 overall optical efficiency. This work shows the possibility to build compact laser systems with average-to-high peak power pulses based on waveguides realized by a femtosecond (fs) laser beam direct writing technique and that are pumped by a fiber-coupled diode laser.

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