Influence of the pulse duration and the experimental approach onto the specific removal rate for ultra-short pulses

2017 ◽  
Author(s):  
B. Jaeggi ◽  
B. Neuenschwander ◽  
S. Remund ◽  
T. Kramer
Keyword(s):  
Pulse Duration ◽  
Experimental Approach ◽  
Removal Rate ◽  
Short Pulses

scholarly journals Pulse Duration and Wavelength Effects of Laser Ablation on the Oxidation, Hydrolysis, and Aging of Aluminum Nanoparticles in Water

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 767 ◽  
Author(s):  
Ke Zhang ◽  
Dmitry S. Ivanov ◽  
Rashid A. Ganeev ◽  
Ganjaboy S. Boltaev ◽  
Pandiyalackal S. Krishnendu ◽  
...  
Keyword(s):  
Pulse Duration ◽  
Morphological Transformation ◽  
Short Pulses ◽  
Al Nanoparticles ◽  
Initial Stage ◽  
Three Stages ◽  
Points Of View ◽  
Hydrolysis Of ◽  
Stable Stage

We analyzed the formation of the aluminum (Al) nanoparticles (NPs) with triangular shape obtained by ablating Al bulk in liquid using pulses with different durations (5 ns, 200 ps, and 30 fs) and wavelengths (355 nm, 800 nm, and 1064 nm). We report three stages of synthesis and aging of Al NPs: Formation, transformation, and stable stage. The NPs prepared by different pulses are almost identical at the initial stage. The effects of duration and wavelength of the ablation pulses on the aging of NPs are revealed. Pulse duration is determined to be essential for morphological transformation of NPs, while pulse wavelength strongly influences particle sizes. NPs produced by ultra-short pulses have smaller sizes and narrow size distribution. We demonstrate that oxidation and hydrolysis of Al in water are the results of ablation for all pulse durations and wavelengths, which also strongly modify the preferable reaction path of NPs in water, thus affecting the composition and morphology of triangle NPs. The results of modeling of the NPs generation in water due to a 50 ps laser pulse interacting with a thick Al target are presented. Water-based effects in the formation of NPs, their evolution, and solidification are considered from the mechanical and thermophysical points of view. The detailed analysis of the modeling results allowed for determination of the main mechanism responsible for the ablation process followed by the NPs formation.

scholarly journals Time-dependent effects in the nonsequential ionization of helium at various wavelengths

2000 ◽  
Vol 18 (3) ◽  
pp. 433-441
Author(s):  
P.P. CORSO ◽  
D.G. LAPPAS ◽  
P.L. KNIGHT
Keyword(s):  
Laser Pulse ◽  
Helium Atom ◽  
Pulse Duration ◽  
Yield Curve ◽  
Underlying Mechanism ◽  
Double Ionization ◽  
Time Dependent ◽  
Short Pulses ◽  
Double Electron ◽  
Electron Ejection

Calculations of the double ionization of a model 1D helium atom interacting with an intense short laser pulse are presented. A substantial signature of nonsequential double ionization is found for all the wavelengths that are considered, from 248 nm to 1064 nm, provided that sufficiently short pulses are employed. We show how one can modify the size of the “knee” structure of the double ionization yield curve by varying the laser pulse duration. The underlying mechanism of the correlated double electron ejection is investigated and discussed.

scholarly journals OPTIMIZATION OF EDM PARAMETERS USING INTEGRATED APPROACH OF RSM, GRA AND ENTROPY METHOD

2013 ◽  
pp. 52-57
Author(s):  
SANJAY KUMAR MAJHI ◽  
M. K. PRADHAN ◽  
HARGOVIND SONI
Keyword(s):  
Pulse Duration ◽  
Pulse Current ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Integrated Approach ◽  
Gray Relational Analysis ◽  
Response Analysis ◽  
Optimization Approach ◽  
Pulse Off Time ◽  
Off Time

This paper presents a hybrid optimization approach for the determination of the optimal process parameters which maximize the material removal rate and minimize surface roughness & the tool wear rate. The input parameters of electrical discharge machining considered for this analysis are pulse current (Ip), pulse duration (Ton) & pulse off time (Toff). The influences of these parameters have been optimized by multi response analysis. The designed experimental results are used in the gray relational analysis & the weight of the quality characteristics are determined by the entropy measurement method. The effects of the parameters on the responses were evaluated by response surface methodology, which is based on optimization results. On the basis of optimization results it has been found that pulse current (Ip) of 5A, a pulse duration (Ton) of 60μs & pulse off time (Toff) 45μs, which are the best combination of this analysis.

scholarly journals Contribution to the Study of Cutting Temperature and Tool Wear

2020 ◽  
Vol 14 ◽  
Keyword(s):  
Experimental Approach ◽  
Cutting Tool ◽  
Removal Rate ◽  
Cutting Temperature ◽  
Machining Process ◽  
The Face ◽  
Surface Regeneration ◽  
Lower Temperature ◽  
Significant Production

The quality of a machined part strongly depends on the state of wear and the cutting tool. This wear is a major problem in the field of industry. This depends on several factors such as the material to be machined, the cutting tool, the cutting conditions and the machining process. All these factors have the corollary of a significant production of heat at the tool-chip interface. This heat induces accelerated wear of the cutting tool, which considerably limits the performance of the machine tool and is mainly detrimental to both the workpiece and the cutting tool. In this study, the main objective is to contribute to the study of the mechanisms of degradation of the tool by carrying out from an experimental approach based on the techniques of thermocouples located in places studied in order to avoid the influence of parasitic and undesirable parameters such as surface regeneration vibrations, etc. This approach is carried out experimentally by measuring the temperature of the cutting face (friction tool / chip interface). From the results collected during the experiment, we can understand the effects of different turning parameters on the temperature developed on the face of the tool and the appropriate turning conditions to obtain a maximum material removal rate at a lower temperature. The results obtained are represented and analyzed graphically.

scholarly journals Influence of the spark heat on the electrode behavior in Powder Mixed-EDM environment

2019 ◽  
Vol 13 (4) ◽  
pp. 6125-6143 ◽  
Author(s):  
M. A. Abbas ◽  
M. A. Lajis ◽  
A. D. Jawad ◽  
E. A. Rahim ◽  
S. Ahmed ◽  
...  
Keyword(s):  
Heat Flux ◽  
Pulse Duration ◽  
Removal Rate ◽  
Maximum Level ◽  
Correlation Factor ◽  
Copper Electrode ◽  
Experimental Results ◽  
Chromium Powder ◽  
Damage Sensing ◽  
Powder Mixed Edm

Most past studies did not attempt to improve the numerical model for the electrode removal rate which depends on the experimental results. Furthermore, these studies have not included the damage-sensing for the electrode in Powder Mixed-EDM (PMEDM) medium. Therefore, the current study aims to enhance this model for the copper electrode based on the heat flux for the spark channel. Besides, it focuses on sensing the copper electrode damage depending on the slope relation between eroding velocity and the pulse duration. In both studies, during machining D2 steel, Nano chromium powder in the dielectric liquid is applied. The correlation factor between the Numerical Heat Flux q(r) and the experimental results for the Tool Wear Rate (TWR) attained is 93.06%. The value of this factor improves the mathematical model for TWR instead of the traditional mechanism that adopts the crater volume. Also, the damage-sensing constant (STD) in the copper electrode is very efficient at the minimum value of the peak current (IP), powder concentration (PC) and the maximum level of the pulse duration (Ton). Thus, the statistical confirmation using Response Surface Methodology (RSM) produced a higher value of the composite desirability (96.76%) and error percent equals to (10.3%-1.55%) and (0.18%-2.40%) for TWR and q(r), respectively. On the other hand, the optimum operation values are IP = 10 Amps, Ton = 30 µs, and PC = 2 g/L. These confirmation values are similar to the trials No. (3) and No. (11). Therefore, these values confirm the main purpose in order to obtain the best performance for TWR at the minimum spark heat.

Effect of composition and grain size on electrical discharge machining of BN–TiB2 composites

1991 ◽  
Vol 6 (11) ◽  
pp. 2457-2462 ◽  
Author(s):  
A.M. Gadalla ◽  
H.S. Bedi
Keyword(s):  
Grain Size ◽  
Liquid Phase ◽  
Pulse Duration ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Water Conductivity ◽  
Conducting Phase ◽  
High Pulse

TiB2 conducts the current and forms a liquid phase at the interface with BN. Neighboring crystals of BN and some TiB2 spall due to thermal shock. During pause periods parts of the liquid and fragments are flushed out by the dielectric. Composites rich in TiB2 or with fine TiB2 grains gave high material removal rates. Increasing the amount of the conducting phase by 10% is as effective as decreasing the grain size from 11 to 7 μm. Coarse TiB2 could withstand high pulse durations before wire breaks. Material removal rate increases with pulse duration, frequency, and current. For the same composition and grain size, increasing the pulse duration or current increased the crater depth (the roughness) up to a certain value, beyond which increasing these parameters yielded a smoother surface. The conductivity of the dielectric was effective only for compositions rich in TiB2 content. In such cases, higher water conductivity lowered the energy required for material removal.

Evaluation of Micro-EDM Milling Performance Using Pulse Discrimination

2014 ◽  
Author(s):  
F. Modica ◽  
G. Guadagno ◽  
V. Marrocco ◽  
I. Fassi
Keyword(s):  
Tool Wear ◽  
Process Parameters ◽  
Pulse Width ◽  
Removal Rate ◽  
Micro Edm ◽  
Erosion Process ◽  
Machining Performance ◽  
Short Pulses ◽  
Milling Performance ◽  
Micro Channels

In this paper, the pulse discrimination of gap voltage and discharge current waveforms occurring during micro-EDM milling of micro-channels is analyzed in relation to process parameters variation and machining performance. The pulse classification algorithm discriminates voltage and current waveforms into four defined pulse types: short, arc, delayed and normal. The micro-channels are manufactured in hardened steel using an energy level corresponding to the finishing regime and varying pulse width, frequency, gain and gap. The analysis shows that when the erosion process is stable, normal discharges are predominant. Delayed and short pulses are very sporadic. A major number of arcs can be detected when the gap is decreased and gain increased, i.e. erosion speed and feed rate are increased and affect in particular tool wear. Also the increase of the pulse width has an effect on tool wear, though the percentage of the arcs remains small. On the contrary, material removal rate does not seem to be apparently related to the percentage of arcs as the process parameters are varied, since these values are spread in a constant range for all parameter combinations. The evaluation of the depth errors does not provide any significant insights about the erosion process in relation to the considered process parameters.

Sign in / Sign up

Export Citation Format

Share Document