scholarly journals Effect of Process Parameters on the Quality of Laser-Cut Stainless Steel Thin Plates

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1224
Author(s):  
Irene Buj-Corral ◽  
Lluís Costa-Herrero ◽  
Alejandro Domínguez-Fernández
Keyword(s):  
Process Parameters ◽  
Laser Cutting ◽  
Pulse Width ◽  
High Speed ◽  
Linear Models ◽  
Dimensional Accuracy ◽  
Pulse Frequency ◽  
Thin Plates ◽  
Dimensional Error ◽  
Frequency Pulse

At present, laser cutting is currently employed to cut metallic plates, due to their good finish and dimensional quality, as well as because of the flexibility of the process to obtain different shapes. In the present paper, surface roughness, dimensional accuracy, and burr thickness of thin plates of 0.8 mm are studied as functions of different process parameters: pulse frequency, pulse width, and speed. Eight different experiments were performed according to a full 23 factorial design, with two replicates each. Square specimens of 10 mm × 10 mm were cut. Arithmetical mean roughness Ra was measured with a contact roughness meter, and the dimensions and burr thickness with a micrometer. Ra values ranged between 1.89 and 3.86 µm, dimensional error values between 0.22 and 0.93%, and burr thickness between 2 and 34 µm. Regression analysis was performed, and linear models were obtained for each response. Results showed that roughness depends mainly on frequency, on the interaction of frequency and pulse width and on pulse width. The dimensional error depends on pulse width, frequency, and the interaction between pulse width and speed. Burr thickness is influenced by frequency, pulse width, and the interaction between frequency and speed. Multi-objective optimization showed that, in order to simultaneously minimize the three responses, it is recommended to use high frequency (80 Hz), high pulse width (0.6 ms), and high speed (140 mm/min). The present study will help to select appropriate laser cutting conditions in thin plates, in order to favor good surface finish and dimensional accuracy, as well as low burr thickness.

Pulsed-DC Electrospray for Biopolymer Particle Production

2009 ◽  
Vol 1239 ◽  
Author(s):  
Cho-Hui Lim ◽  
Kiersten R Schierbeek ◽  
Michael E Mullins
Keyword(s):  
Pulse Width ◽  
Particle Production ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Process Conditions ◽  
High Duty Cycle ◽  
Pulsed Dc ◽  
High Pulse ◽  
Long Pulse ◽  
Frequency Pulse

AbstractPLLA microparticles were successfully fabricated via pulsed-DC electrospray. In this study, we investigated the effect of the pulsed voltage characteristics (e.g. pulse frequency, pulse amplitude and pulse width) on the particle’s size. We found that pulse frequency, pulse amplitude, pulse width, and the combinations of these factors had a statistically significant effect on the particle’s size. The process conditions to obtain smaller particles with uniform shape and size are a low pulse frequency, high pulse amplitude, and long pulse width (or a high duty cycle).

High-Speed Fabrication of Microchannels Using Line-Based Laser Induced Plasma Micromachining

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Ishan Saxena ◽  
Rajiv Malhotra ◽  
Kornel Ehmann ◽  
Jian Cao
Keyword(s):  
Process Parameters ◽  
Optical System ◽  
Pulse Energy ◽  
High Speed ◽  
Microfluidic Devices ◽  
Pulse Frequency ◽  
Free Form ◽  
Laser Induced Plasma ◽  
Circular Spot ◽  
Energy Pulse

Microtexturing of surfaces has various applications that often involve texturing over large (macroscale) areas with high precision and resolution. This demands scalability and speed of texturing while retaining feature sizes of the order of a few microns. Microchannels are a versatile microfeature, which are often used in microfluidic devices and can be arrayed or joined to form patterns and free-form geometries. We present a technique to fabricate microchannels on surfaces with high-speed and by using a multimaterial process, namely, laser induced plasma micromachining (LIPMM). The process has the potential to machine metals, ceramics, polymers, and other transparent, brittle, and hard-to-machine materials. The presented technique uses an optical system to modify the laser spot into the shape of a line, to fabricate microchannels directly without scanning as in the case of a regular circular spot. The process schematics are shown, and micromachining experiments on polished aluminum are discussed. Moreover, it is shown that the depth and width of the channels may be varied by changing process parameters like the pulse energy, pulse frequency, and number of exposures.

A New Method of Pulse Technique in Gasbag Polishing

2010 ◽  
Vol 431-432 ◽  
pp. 293-296 ◽  
Author(s):  
Shi Ming Ji ◽  
Wei Dong Zhang ◽  
Ming Sheng Jin ◽  
Li Zhang ◽  
Gao An Zheng
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Pulse Width Modulation ◽  
Switching Time ◽  
Pulse Frequency ◽  
Polished Surface ◽  
Main Principle ◽  
Pulse Technique ◽  
Series Of Experiments ◽  
Frequency Pulse

Gasbag polishing is an automatic, flexible, controllable and practical technique, which has wide application prospect. A pulse technique based on robotic gasbag polishing system is proposed. Its main principle is to use the Pulse Width Modulation (PWM) technique to control the switching time of High-speed Solenoid Valve (HSV). It can not only control the internal pressure of gasbag, but also make the rubber gasbag present pulsation with PWM technique. Moreover, the performance of pulse technique is presented and the effects of different frequency pulse pressure on the polished surface roughness are analyzed through a series of experiments. At last, experimental results show that the pulse technique can improve the polished surface roughness more rapidly in certain extent with appropriate pulse frequency and process parameters comparing with conventional gasbag polishing way.

scholarly journals Investigation on the Electrochemical Micromachining of Micro Through-Hole by Using Micro Helical Electrode

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 118 ◽  
Author(s):  
Baohui Liu ◽  
Hang Zou ◽  
Haixuan Luo ◽  
Xiaoming Yue
Keyword(s):  
Process Parameters ◽  
High Speed ◽  
Pulse Frequency ◽  
Machining Process ◽  
Electrochemical Micromachining ◽  
Good Effect ◽  
Machining Accuracy ◽  
High Speed Rotation ◽  
Helical Electrode ◽  
Through Hole

The instability of machining process caused by the difficulty of the electrolyte refresh in electrochemical micromachining (EMM) of micro through-hole has been an unsolved problem. Thus, this paper investigates the electrochemical micromachining of micro through-hole by using a micro helical electrode combining with the jetting electrolyte. With the help of high-speed rotation of micro helical electrode and its spiral shape, the internal electrolyte can be stirred while the external jetting electrolyte can flow into the hole along the spiral groove to refresh the electrolyte effectively, thereby, improving the machining stability of EMM. Firstly, the influence of the process parameters on the fabrication of micro through-hole in the EMM by using micro helical electrode without non-conductive mask is investigated. Based on the optimization of the process parameters, a micro through-hole with an inlet dimension of 121.6 μm and an outlet dimension of 114.9 μm is obtained successfully. Furthermore, this paper also tries to use the micro helical electrode coated with the non-conductive mask to decrease the bad influence of the stray corrosion attack. It is found that the non-conductive mask coated on the surface of micro helical electrode can improve the machining accuracy significantly under the condition of low pulse frequency (≤1 KHz). However, its good effect on preventing the stray corrosion decreases along with the increase of the pulse frequency.

Intelligent Modelling and Multi-Objective Optimisation of Laser Beam Cutting of Nickel Based Superalloy Sheet

2013 ◽  
Vol 3 (2) ◽  
pp. 1-16 ◽  
Author(s):  
Amit Sharma ◽  
Vinod Yadava ◽  
K. B. Judal
Keyword(s):  
Laser Beam ◽  
Process Parameters ◽  
Pulse Width ◽  
Thin Sheet ◽  
Cutting Speed ◽  
Pulse Frequency ◽  
Good Prediction ◽  
Ann Model ◽  
Nsga Ii ◽  
Nickel Based Superalloy

In the present study, a novel technique, namely, evolutionary non-dominated sorting genetic algorithm-II (NSGA-II) was used in conjunction with developed artificial neural network (ANN) model to select optimal process parameters for achieving the better process performance in LBC. First, ANN with backpropagation algorithm was used to model the LBC of nickel based superalloy sheets. The input process parameters taken were oxygen pressure, pulse width, pulse frequency and cutting speed. The performance characteristics of interest in nickel based superalloy thin sheet cutting are average kerf taper and surface roughness. The ANN model was trained and tested using the experimental data obtained through experimentation on pulsed Nd-YAG laser beam machining system. The 4-10-11-2 backpropagation architecture was found more accurate and generalized for given problem with good prediction capability. The results show that the developed modelling and optimization tool is effective for process parameter optimization in LBC process. The optimization of the process suggests that for achieving high cut quality characteristics the pulse width, pulse frequency and cutting speed are set to lower limit within the available range and gas pressure is set to a level which is sufficient to remove the molten metal from the kerf.

scholarly journals Multi-objective Optimization of Kerf-taper and Surface-roughness Quality Characteristics for Cutting-operation On Coir and Carbon Fibre Reinforced Epoxy Hybrid Polymeric Composites During CO2-Pulsed Laser-cutting Using RSM

2021 ◽  
Author(s):  
Yadvinder Singh ◽  
Jujhar Singh ◽  
Shubham Sharma ◽  
Vivek Aggarwal ◽  
Catalin I. Pruncu
Keyword(s):  
Carbon Fibre ◽  
Laser Cutting ◽  
Pulse Width ◽  
Cutting Speed ◽  
Pulse Frequency ◽  
Quality Characteristics ◽  
Gas Pressure ◽  
Coir Fibre ◽  
Kerf Taper ◽  
Cut Quality

AbstractCurrent research focuses on optimizing various quality characteristics for kerf geometry generated through laser cutting of Coir fibre/carbon fibre/epoxy resin hybrid composite adjacent to straight cut profile employing pulsed CO2 laser system. The Kerf taper (KT) and the Surface roughness (SR) are the main quality parameters discussed. Dependent on significant process parameters, namely gas pressure, cutting speed, pulse frequency and pulse width predictive models were developed. In accordance with Taguchi's L9 orthogonal array (OA), the cutting trials are designed. Process-parametric optimization was performed using Response Surface Methodology (RSM). Furthermore, experiments were performed to obtain experimental data for the analysis of cut quality features. The impact of the input variables on the response characteristics is also explored. The morphological characterizations have been performed to analysis the effect of machining-variables and cut-quality for the top and bottom kerf widths with various laser cutting variables in the pulse laser-cutting of Coir-fibre/carbon-fibre/epoxy-resin hybrid composite. For SR and KT, the developed second order surface response model was found very successful. The optimal levels of cutting variables for KT are established at Gas pressure-6 N/mm2, pulse width-2.04 ms, cutting speed-8.01 mm/s, pulse frequency-15 Hz, for sample A1, Gas pressure-5.47 N/mm2, pulse width-2.5 ms, cutting speed-8.81 mm/s, pulse frequency-8.43 Hz, for sample A2, Gas pressure-3.85 N/mm2, pulse width-1.5 ms, cutting speed-9.06 mm/s, pulse frequency-5 Hz, for sample A3 additionally for SR Gas pressure-2 N/mm2, pulse width-1.5 ms, cutting speed-7 mm/s, pulse frequency-5 Hz, for sample A1, Gaspressure-2.36 N/mm2, pulse width-1.5 ms, cutting speed-7 mm/s, pulse frequency-15 Hz, for sample A2, Gaspressure-6 N/mm2, pulse width-1.5 ms, cutting speed-11 mm/s, pulse frequency-8.73 Hz, for sample A3. Regression results and linear and square impact of laser cutting variables have been revealed to be important to validate the model.

scholarly journals A generalised approach on kerf geometry prediction during CO2 laser cut of PMMA thin plates using neural networks

2021 ◽  
Author(s):  
John Dimitrios Kechagias ◽  
Konstantinos Ninikas ◽  
Panagiotis Stavropoulos ◽  
Konstantinos Salonitis
Keyword(s):  
Laser Cutting ◽  
Linear Models ◽  
Cutting Speed ◽  
Kerf Width ◽  
Thin Plates ◽  
Beam Power ◽  
Linear Modeling ◽  
A Value ◽  
Kerf Angle ◽  
Precise Prediction

Abstract This study presents an application of feedforward and backpropagation neural network (FFBP-NN) for predicting the kerf characteristics, i.e. the kerf width in three different distances from the surface (upper, middle and down) and kerf angle during laser cutting of PMMA thin plates. Stand-off distance, cutting speed and beam power are the studied parameters for the case of low power CO2 laser cutting. A three-parameter three-level full factorial array has been used and twenty-seven (33) cuts were performed. Subsequently, the kerf width and angle were measured and analysed through ANOM, ANOVA and interaction plots. The statistical analysis highlighted that linear modeling is insufficient for the precise prediction of kerf characteristics. A FFBP-NN was developed, trained, validated and generalised for the accurate prediction of the kerf geometry. The FFBP-NN achieved an R-sq value of 0.98, in contrast to the ANOVA linear models which achieved a value of about 0.90.

scholarly journals Optimization of Process Parameters of Laser Cladding 304L Alloy Powder Based on Orthogonal Experiment

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Linsen SHU ◽  
Bo WANG ◽  
Yayin HE
Keyword(s):  
Laser Cladding ◽  
Process Parameters ◽  
Alloy Powder ◽  
Pulse Width ◽  
Pulse Current ◽  
Orthogonal Experiment ◽  
Pulse Frequency ◽  
Optimal Combination ◽  
Optimal Process ◽  
Cladding Layer

In order to find the optimal combination of process parameters for laser cladding 304L alloy powder on the surface of 45 steel, a combination method of single factor test and multi-factor orthogonal experiment was used to perform the single pulse laser cladding experiment. The effects of process parameters (pulse current A, pulse width B, pulse frequency C,defocus distance D, scan velocity E) on the morphology and performance of cladding layer was studied by range analysis, and the optimal combination of cladding parameters is calculated by fuzzy comprehensive evaluation. The results show that different process parameters have different effects on the morphology of the cladding layer and scanning velocity E and defocus distance D are the most important influencing factor of cladding morphology. The effect on cladding width is D> C > A > B > E and the effect on cladding height is E > A > C > D > B. The optimal combination of cladding width is A4B4C4D4E2. The optimal combination of cladding high is A2B1C1D4E1. The comprehensive optimal process parameters are pulse current 210A, pulse width 3.6ms, pulse frequency 16Hz, defocus distance +10mm and scanning speed 240mm/min. The average hardness of the cladding layer, melting pool, heat-affected zone and substrate under the optimal process parameters is 406.2 HV0.5, 470.8 HV0.5, 230.5HV0.5 and 202.0HV0.5, respectively. The 304L cladding layer on 45 steel surface is stable in width, height and surface quality under comprehensive optimal parameters.

scholarly journals A generalised approach on kerf geometry prediction during CO2 laser cut of PMMA thin plates using neural networks

2021 ◽  
Author(s):  
John Dimitrios Kechagias ◽  
Konstantinos Ninikas ◽  
Panagiotis Stavropoulos ◽  
Konstantinos Salonitis
Keyword(s):  
Laser Cutting ◽  
Linear Models ◽  
Cutting Speed ◽  
Thin Plates ◽  
Anova Analysis ◽  
Analysis Of Means ◽  
Kerf Angle ◽  
Precise Prediction ◽  
Parameter Values ◽  
Full Factorial

Abstract This study presents an application of feedforward and backpropagation neural network (FFBP-NN) for predicting the kerf characteristics, i.e. the kerf width in three different distances from the surface (upper, middle and down) and kerf angle during laser cutting of 4 mm PMMA (polymethyl methacrylate) thin plates. Stand-off distance (SoD: 7, 8 and 9 mm), cutting speed (CS: 8, 13 and 18 mm/sec) and laser power (LP: 82.5, 90 and 97.5 W) are the studied parameters for low power CO2 laser cutting. A three-parameter three-level full factorial array has been used, and twenty-seven (33) cuts are performed. Subsequently, the upper, middle and down kerf widths (Wu, Wm and Wd) and the kerf angle (KA) were measured and analysed through ANOM (analysis of means), ANOVA (analysis of variances) and interaction plots. The statistical analysis highlighted that linear modelling is insufficient for the precise prediction of kerf characteristics. An FFBP-NN was developed, trained, validated and generalised for the accurate prediction of the kerf geometry. The FFBP-NN achieved an R-all value of 0.98, in contrast to the ANOVA linear models, which achieved Rsq values of about 0.86. According to the ANOM plots, the parameter values which optimize the KA resulting in positive values close to zero degrees were the 7 mm SoD, 8 mm/s CS and 97.5 W LP.

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