Top Kerf Width Research Articles

Machinability and Delamination Studies on Glass Fiber Reinforced Polymer Matrix Composite Cut by Abrasive Water Jet Machine

Abrasive water jet machining possesses inherent technological and manufacturing advantages unmatched by most machine tools. They are generally used in automotive, marine and aerospace industries for machining of composites. However, abrasive water jet cutting of GFRP laminates possesses several challenges, such as surface finish and delamination of the cutspecimen. Henceforth, more experimental work is needed to provide sufficient machinability databases for manufacturing industries. This paper presents an experimental study for cutting GFRP laminates. Different AWJM conditions including pressure, traverse speed and abrasive flow rate are analyzed using full factorial design of experiments. Machining process responses such as surface roughness (Ra), top and bottom kerf width, kerf taper, delamination of fibers have been evaluated using analysis of variance (ANOVA) technique. The optimum process parameters for AWJM of glass fiber reinforced polymers have beensuggested.

Simulation, statistical modeling, and optimization of CO2 laser cutting process of polycarbonate sheets

Laser cutting well-known as a manufacturing process is a rapid, repeatable, and reliable method that is frequently used for cutting various materials such as thermoplastics. Due to their physical and chemical properties such as fatigue resistance, high toughness, and re-melting properties, thermoplastics such as polycarbonate are widely used in automotive parts, electronics, etc. In this study, a numerical simulation of the laser cutting process by a finite element method is developed. The sample simulated in this research is a 3.2 mm thick Polycarbonate sheet that is subjected to the laser cutting process by a low power continuous CO2 laser. The effects of the laser cutting process parameters such as laser power, cutting speed, and laser focal plane position on the top and bottom kerf width, top heat-affected zone, the ratio of upper kerf width to lower kerf width and taper kerf are investigated by statistical techniques of variance analysis. Choosing an appropriate Gaussian distribution is studied as well. The results show that the laser scanning speed has a significant effect on the top kerf width. By choosing a cutting speed of 20 mm/s and a focal length of -3, the taper kerf is minimized. By increasing the laser cutting speed from 4 to 20 mm/s and decreasing the laser power from 50 to 20 W, the heat-affected zone decreases. The developed analysis can predict the depth of kerf in a continuous mode for different values of laser power, speed, and laser focal plane.

Integration of quality characteristics models as a software-based graphical interface for machining of AA6351 aluminum alloy using abrasive water jet process

In this paper, semi-empirical models of the performance characteristics, i.e., material removal rate, average surface roughness, kerf top width and taper angle in abrasive water jet machining (AWJM) of AA6351 aluminum alloy are reported. These models are developed using the dimensional analysis based on Buckingham ∏ theorem, and the proposed models for the considered performance parameters are analyzed both qualitatively and quantitatively using experimental data. Likewise, artificial feed forward neural network has been attempted to predict the considered performance parameters of AWJM process. For this purpose, different numbers of neurons have been tried at the hidden layer to obtain the best neural network. The validity of semi-empirical models and artificial neural network is verified using the experimental results. Furthermore, software prototype graphical user interface (GUI) is developed which allows user to interact with the models to predict the considered performance characteristics. The GUI is tested and validated through the experimental results. The results proved the functional capability and effectiveness of the GUI in predicting the performance characteristics.

Investigation of kerf Characteristics in Abrasive Water Jet Machining of Inconel 600 using Response Surface Methodology

Abrasive water jet machining (AWJM) has found its application in the manufacturing industries for machining hard materials with precision. A degree of high precision in machining of complex geometries makes AWJM valuable. The selection of optimum process parameters is important to the resulting quality of machined parts. In this study, an experimental investigation was conducted to evaluate the machinability of Inconel 600. A response surface methodology (RSM) is used to determine the influence of the AWJM process parameters on the considered performance characteristics, i.e., kerf top width (KTW) and taper angle. The analysis of variance is performed to obtain the contribution and influence of each process parameter on the considered responses. The value of R-Squared obtained for KTW and taper angle using regression model is 0.97 and 0.96 respectively. The optimum setting of the parameters for single and multiple response characteristics are obtained using the desirability analysis of RSM. The results obtained using desirability analysis of RSM is validated by conducting the confirmation experiments. The experimental confirmatory values obtained for the considered performance parameters KTW and taper angle as 27.138 and 0.125 respectively. The corresponding value of error obtained as 0.383 and 0.013 respectively. Further, an optimum set is obtained with KTW as 27.461 mm and taper angle as 0.582° for multiple response optimisation.

Microchannel fabrication and metallurgical characterization on titanium by nanosecond fiber laser micromilling

ABSTRACTLaser micromilling technique is used to manufacture microchannel on metals and nonmetals. Microfeatures ≤100 µm are still challenging for fabrication by common methods. Nanosecond fiber laser micromachining has become more popular owing to its prospective implementation in laser micromilling. Microchannel application relies on its geometric dimension, profile, and surface quality. In this study, an attempt was made to explore the impact of process parameters scanning times, scanning velocity, pulse repetition rate, and assist gas pressure on top kerf width, taper, surface roughness, and metal removal rate in laser micromilling experimentally. Microchannel width varied between 45.5 and 70.9 µm. A regression model has been developed for each response. ANOVA (analysis of variance) has been carried out to remove insignificant parameters. Thermal stress analyzed by surface cracks inside microchannel by Scanning Electrone Microscopy (SEM) images. Higher PRR, lower no. of scans, higher scanning speed and high air pressure found suitable for lesser surface cracks. Redeposition observed at slower scanning velocity and minimum scanning times. Oxidation zone from boundary of channel varies between 37 and 58 µm. Oxide formed on Ti surface which increases oxygen content toward center of channel from 51.08 to 76.22% compared to outside surroundings.

Optimizacija karakteristika kvaliteta reza kod rezanja laserom BFRP kompozita korišćenjem genetskog algoritma baziranog na grej relacionoj analizi

In laser beam machining, the geometrical precise cutting of fiber reinforced polymer (FRP) composite materials is a challenging task in order to produce a higher quality cut. The aim of the present research is to determine optimum levels of cutting parameters able to provide geometrically accurate cut for 1.60 mm thick Basalt Fiber Reinforced Polymer (BFRP) composite laminate. The total of 42 experiments have been performed on a 250W pulsed Nd:YAG laser system. During experimentation, the lamp current, pulse width, pulse frequency, compressed air pressure and cutting speed have been varied to evaluate different kerf quality characteristics such as top and bottom kerf width, top & bottom kerf deviation, and kerf taper. Experimental results have been used to single index optimization of evaluated multiple kerf quality characteristics. A hybrid grey relational analysis coupled with genetic algorithm approach has been adopted for the optimization. The optimum levels of cutting parameters have been found at moderate lamp current (184.5 Amp), lower pulse width (2 ms), compressed air pressure (8 kg/cm²) and cutting speed (50 mm/min) and higher pulse frequency (30 Hz). Finally, confirmation experiments have been conducted and it has been observed that optimal levels of cutting parameters are able to improve top kerf width, bottom kerf width, top kerf deviation, bottom kerf deviation, and kerf taper by 13.33 %, 13.29 %, 23.52 %, 23.07 %, and 10.83 %, respectively. From the experimental results, it has been found that lamp current is the most significant parameter for all kerf quality characteristics.

Investigation of optimal process parameters for laser cutting of Inconel-718 sheet

Precise machining of advance material like Inconel-718 is an emerging need. Selection of an appropriate optimal range of cutting parameters is quite essential to achieve the high-quality cut and is a challenging task within this domain of study. The aim of this research is to develop a robust prediction model, which can suggest the desired range of cutting parameters for accomplishing better cutting quality, precision, and geometrical accuracy. Experiments have been performed on a 300 W (CNC-PCT 300) pulsed Nd: YAG laser cutting system at various levels of input cutting parameters, namely gas pressure, standoff distance, cutting speed, and laser power. Thereafter, response surface methodology has been adopted to develop mathematical models in terms of aforementioned input cutting parameters for geometrical quality characteristics: top kerf width and bottom kerf width. These developed models have been validated by comparing the predicted values with the experimental ones. Further, these models have been optimized using the multiobjective genetic algorithm in order to ascertain the optimal range of cutting parameters pertaining to better quality cut with high precision and geometrical accuracy.

Improving laser cutting quality of polymethylmethacrylate sheet: experimental investigation and optimization

Motivated by the need to enhance the kerf quality during cutting of Poly(methyl methacrylate) (PMMA) sheets using pulsed CO2 laser beam, this study presents an experimental investigation and optimization of laser cutting parameters including cutting speed, assisted gas pressure, laser beam power, and sheet thickness. The kerf quality characteristics including the top kerf width, bottom kerf width, and kerf taper have been considered as the process responses and have been measured using polarized light microscope. The experiments were designed and planned using Taguchi L18 orthogonal array with a mixed design. The effects of different cutting parameters on the kerf characteristics have been statistically analyzed using analysis of variance technique (ANOVA). The obtained results revealed that any increase in cutting parameters will result in increasing the top and the bottom kerf widths, while increasing cutting speed or laser power results in increasing the kerf taper. Second order regression models have been developed to model different kerf characteristics as functions of the process parameters. Genetic algorithm (GA) has been used to select the optimal cutting parameters using the developed regression model as an objective function to minimize the kerf taper. A considerable improvement in kerf quality has been achieved and the obtained results have been verified using confirmation experiments. The application of the proposed approach is capable to reduce the kerf taper from 1.92° to 0.02° while maintaining the minimum kerf width at a reasonable value (less than 0.5 mm).

Intra-class and inter-class tool discrimination through micro-CT analysis of false starts on bone.

Micro-CT has successfully been applied to the characterization of false starts (FSs) and, among several parameters, kerf width seems to correlate to the tool blade. The aim of the present study was to evaluate the diagnostic value of micro-CT for the differentiation of saw marks produced by different classes of saws and by saws belonging to the same class and differing only in number of teeth per inches (TPI). A morphological and morphometric analysis of 84 marks, produced by 6 saws belonging to 3 morphological classes, was performed. In the experimental cohort, for each parameter, statistically significant differences in intra- and inter-class analysis were searched for and cut-offs were established. The diagnostic accuracy of cut-offs was assessed through statistical analyses on the validation cohort. The morphological assessment did not allow to differentiate saws differing only in TPI. Angle 1 and top kerf width, respectively for cross-cut and rip-cut saws with alternating set, allowed a good discrimination between FSs produced by tools belonging to the same morphological class. High positive predictive values were found in intra-class analyses, while results in inter-class analyses were less encouraging. In cases of dismemberment, a micro-CT-based analysis of FSs is strongly suggested as a part of a multistep and multimodal methodology of assessment, which includes scanning electron microscopy and stereomicroscopy. A morphological assessment should be followed by an experimental trial and by a morphometric analysis. Further studies are needed to evaluate hampering factors, such as damage by physico-chemical agents.

Dimensional accuracy improvement by parametric optimization in pulsed Nd:YAG laser cutting of Kevlar-29/basalt fiber-reinforced hybrid composites

Laser cutting proves its suitability for cutting of single fiber-reinforced polymer (FRP) composites compared with conventional cutting techniques due to reduced fiber delamination, matrix cracking and fiber pullout. However, the performance of the laser cutting process of hybrid FRP composites is yet to be revealed, which paves the way of the present study. In this article, an experimental investigation of the laser cutting process is carried out on 1.35-mm-thick Kevlar-29 and basalt fiber-reinforced polymer (KBFRP) hybrid composite laminates using 250 W pulsed Nd:YAG laser system. The performance of laser cutting was evaluated by quantifying different kerf quality characteristics such as top and bottom kerf width, top and bottom kerf deviation and kerf taper. These kerf quality characteristics define the geometrical accuracy of the laser cut. Response surface methodology-based Box–Behnken design was adopted for conducting the experiments with varied settings of laser cutting parameters, viz. lamp current, pulse width, pulse frequency, compressed air pressure and cutting speed. Second-order regression models of each response were developed and validated by using standard error plots. A parametric effect analysis was carried out by using the variation of performance measures predicted through developed mathematical models. In order to achieve the optimal levels of the process parameters for all kerf quality characteristics, a self-developed python language-coded TLBO algorithm was used. Finally, the confirmation experiments were performed at obtained optimal levels of laser cutting parameters. An overall improvement of 22.23% in multiple kerf quality characteristics was achieved through optimal settings of laser cutting parameters. The individual improvement of 11.44%, 8.47%, 17.65%, 15.22% and 58.87% was recorded in top kerf width, bottom kerf width, top kerf deviation, bottom kerf deviation and kerf taper, respectively. The developed mathematical models and suggested optimal conditions are able to provide direction to the researchers for obtaining higher-dimensional accuracy in Nd:YAG laser cutting of KBFRP hybrid composites.

Prediction of optimal cut quality characteristic of Inconel 718 sheet by genetic algorithm and particle swarm optimization

Selection of an appropriate optimal range of cutting parameters during the machining of Inconel-718 is quite essential to achieve the high-quality cut and is a challenging task within this domain of study. The aim of this research is to develop a robust prediction model which can suggest the desired range of cutting parameters for accomplishing better cutting quality, precision, and geometrical accuracy. Experiments have been performed on a 300 W (CNC-PCT 300) pulsed Nd: YAG laser cutting system at various levels of input cutting parameters, viz., gas pressure, standoff distance, cutting speed, and laser power. Thereafter, the artificial neural network technique has been adopted to develop mathematical models in terms of aforementioned input cutting parameters for geometrical quality characteristics: Top Kerf Width, Bottom Kerf Width, and Kerf Taper. These developed models have been validated by comparing the predicted values with the experimental ones. Furthermore, these models have been optimized using a multiobjective genetic algorithm and particle swarm optimization techniques, in order to ascertain the optimal range of cutting parameters pertaining to better quality cut with high precision and geometrical accuracy.

Prediction of geometric quality characteristics during laser cutting of Inconel-718 sheet using statistical approach

Machining of advanced material like Inconel-718 with accuracy and precision is an emerging need. Selection of an appropriate optimal range of cutting parameters is quite essential to achieve high-quality cut and is a challenging task within this domain of study. The aim of this research is to develop a robust prediction model which can suggest the desired range of cutting parameters for accomplishing better cutting quality, precision, and geometrical accuracy. Experiments have been performed on a 300-W (CNC-PCT 300) pulsed Nd:YAG laser cutting system at various levels of input cutting parameters, viz. gas pressure, standoff distance, cutting speed and laser power. Thereafter, response surface methodology has been adopted to develop mathematical models in terms of aforementioned input cutting parameters for geometrical quality characteristics: Top Kerf Width (TKW) and Bottom Kerf Width (BKW). The percentage error in the prediction models has been found as 1.981% and 1.511% for TKW and BKW, respectively. These developed models have been validated by comparing the predicted values with the experimental ones. Further, these models have been used to determine the dependency of responses on input parameters and to ascertain an optimal range of cutting parameters pertaining to better quality cut with high precision and geometrical accuracy. Moreover, it has also been found that the dependency of input parameters on output is non-monotonous in nature.

Multi-objective Optimization of Parameters in Abrasive Water Jet Machining of Carbon-Glass Fibre-Reinforced Hybrid Composites

In the present work, first an attempt has been made to prepare carbon, glass and carbon-glass fibre-reinforced polymer composites, and later, machining of these composites is done on abrasive water jet machine (AWJM) to compare and optimize the machining parameters. Actually, the carbon fibre-reinforced polymer (CFRP) composites, glass fibre-reinforced polymer (GFRP) composites and carbon-glass fibre-reinforced polymer (CGFRP) composites are prepared through vacuum bagging process by using epoxy resin as the polymer matrix. The machining experiments are conducted to analyse the effects of the predominant machining parameters, i.e. cutting speed rate, feed rate and stand-off distance on the required machining characteristics, i.e. surface roughness (Ra), kerf top width (kw) and material removal rate (MRR). The range of values of each parameter is set at three different levels, and Taguchi’s L9 orthogonal array is used to design factors so that all the interactions between the response variables and machining variables can be investigated. Based on the experimental values, second-order regression equations are fitted between each of the response parameters and the machining parameters using Minitab 18 software. The equations are then optimized by defining the three equations of Ra, kw and MRR as the three objectives of a multi-objective optimization problem (MOOP) using a multi-objective optimization algorithm called Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II). Single best compromise solutions with respect to the MOOPs of GFRP, CFRP and CGFRP composites are also determined from the Pareto optimal solutions obtained by NSGA-II. Finally, confirmation tests are conducted on specimens of GFRP, CFRP and CGFRP composites machined at their corresponding optimum parameters given by the GA. It is observed that the optimum values of Ra, kw and MRR of all the optimization problems are closer to the corresponding experimental values of confirmation tests.

Experimental and parametric evaluation of cut quality characteristics in CO2 laser cutting of polystyrene

Cutting characteristics such as heat affected zone (HAZ), top and bottom kerf widths, ratio of top kerf width to bottom kerf width, and dross height are so reliant on process condition in the laser cutting of polymer materials. In the present research, a 60 (W) continuous wave CO2 laser cutting machine was used for cutting the extruded samples of Polystyrene sheet with the thickness of 3 mm. The experiments were designed based on the statistical method, design of experiments. Three variables considered as process parameters including laser power (in three level of 60, 70 and 80 W), cutting velocity (in three level of 6, 10, 14 mm/s) and cutting with covering gas or without gas. The results indicated that the maximum feasible laser power and increasing cutting velocity using compressed air resulted in decreasing HAZ width. By gradual increase of the laser power the cutting mechanism converts from melting to evaporation. Increasing laser power and cutting velocity individually made the dross height smaller. The process parameters were optimized to achieve minimum top kerf width, minimum HAZ width, and ratio equal to 1.

Parameter Optimization for CO2 Laser Cutting of Wood Polymer Composite (WPC)

Wood polymer composites (WPC) are being used widely in various industries due to its wood-like appearance and durability which makes it a suitable substitute for wood in internal decorations. This study involves cutting the WPC (20% wood) of 8mm thickness using CO2 laser cutting machine and the best parameter is obtained in order to get the best cut. The laser cutting machine used in this experiment has a power rating of 50W and the experimental procedures involves variable power setting from 60% - 80%. The nozzle height was also varied ranging from 4mm to 6mm and the cutting speed from 2 – 4 mm/s. The cut material was analysed by taking the reading of top kerf width. The best parameter is then used to cut decorative wood panels which imitate traditional Malay wood carvings (papan pemanis) to be installed at homes. Through the analysis, there are total 10 solutions being generated which will produce good cut quality.

Parametric analysis of process parameter for Laser cutting process on SS-304

Stainless steel is an important engineering material that is difficult to be cut by oxy-fuel methods because of the high melting point and low viscosity of the formed oxides. However, it is suitable to be cut with help of laser. The objective of this work is to do parametric analysis of process parameters for fiber laser cutting system on surface characteristics of the cut section in the cutting of 3 mm Stainless Steel (SS) sheet (ASTM 304). In this study, the laser cutting parameters such as laser power, cutting speed and gas pressure were analyzed and optimized with consideration of workpiece surface roughness and top kerf width. Design of experiments (DOE) technique was implemented to analyze all three parameters. It was observed that the laser power had more effect on responses rather than cutting speed and gas pressure.

Abrasive Water Jet Machining of Multidirectional CFRP Laminates

Abrasive water jet machining (AWJM) is widely used in aerospace, marine and automotive industries for trimming composites. However, AWJM demonstrates some challenges when cutting carbon fibre reinforced plastic (CFRP) composites materials such as cut accuracy and quality. More experimental work is needed to provide sufficient machinability databases for manufacturing engineers. This paper presents an experimental study and statistical analysis for cutting 2 lay-up configurations of multidirectional CFRP laminates. Different AWJM conditions including jet pressure, feed rate, and standoff distance are experimented using full factorial design of experiments. Machining process responses such as top and bottom kerf width, kerf taper, machinability and surface characteristics have been evaluated using analysis of variance (ANOVA) technique. A process cost model for the AWJM is presented.

Optimization of CO2 Laser Cutting of Stainless Steel Sheet for Curved Profile

Laser cutting is one of the most widely used thermal energy based non-contact type advance machining process. In recent years, considerable experimental investigations have been carried out aiming at improving laser cutting process performance. In this work CO2 laser cutting parameters on stainless steel 304 width 2.5 mm thickness were studied. The cut quality achieved minimum kerf width to cut stainless steel sheet depends on appropriate selection process parameters was investigated. The parameters consider to include laser output power, cutting speed, gas pressure. The effect of cutting parameter on the cut quality was further investigated by monitoring top kerf width, and bottom kerf width using box –behnken designing the response surface methodology. And finally optimized best CO2 laser cutting parameters are selected by using genetic algorithm approach.

Investigation of Laser Cutting Width of LiCoO2 Coated Aluminum for Lithium-Ion Batteries

Lithium-ion batteries are widely used for many applications such as portable electronic devices and Electric Vehicles, because they have lighter weight, higher energy density, higher power density, and a higher energy-to-weight ratio than other types of batteries. Conventional contact-based cutting technology may be inefficient whenever cell design is changed since lithium-ion battery cells are not standardized. Furthermore, the conventional cutting may result in process instability and a poor cut quality due to the tool wear so that it leads to short circuits and local heat generation. These process instability and inefficiency may be solved by laser cutting due to advantages such as clean cutting edge, less deformation, applicability to almost all materials, possibility of precision processing, and easy modification of cutting path. Despite the importance of the laser cutting research, no clear definition of cutting widths has been presented, and there is lack of knowledge to understand the effect of laser parameters on cutting widths. Therefore, this research examines the surface of cathode cut by a laser and defines cutting widths such as top width, melting width, and kerf width. The relationship between the laser parameters and cutting characteristics with defined widths are studied. When the volume energy is less than 6.0172 × 10 10 J / m 3 , no active electrode material is removed. When the laser power is greater or equal to 100 W, both the top and melting widths are clearly observed. The laser power of 50 W can selectively ablate the active electrode material with the material removal rate of 32.14–55.71 mm 3 / min . The threshold volume energy to fully penetrate the 50 μm-thick current collector is between 9.6275 × 10 10 – 8.0229 × 10 10 J / m 3 . All clearance width is less than 20 μm, while the clearance width interestingly exceeds 20 μm when the laser power is 200 W. The effect of material properties on heat transfer using the one dimensional transient semi-infinite conduction model is investigated. In addition, five types of physical characteristics are defined and discussed.

Enhancement of low power CO2 laser cutting process for injection molded polycarbonate

Laser cutting technology is a non-contact process that typically is used for industrial manufacturing applications. Laser cut quality is strongly influenced by the cutting processing parameters. In this research, CO2 laser cutting specifications have been investigated by using design of experiments (DOE) with considering laser cutting speed, laser power and focal plane position as process input parameters and kerf geometry dimensions (i.e. top and bottom kerf width, ratio of the upper kerf to lower kerf, upper heat affected zone (HAZ)) and surface roughness of the kerf wall as process output responses. A 60 Watts CO2 laser cutting machine is used for cutting the injection molded samples of polycarbonate sheet with the thickness of 3.2mm. Results reveal that by decreasing the laser focal plane position and laser power, the bottom kerf width will be decreased. Also the bottom kerf width decreases by increasing the cutting speed. As a general result, locating the laser spot point in the depth of the workpiece the laser cutting quality increases. Minimum value of the responses (top kerf, heat affected zone, ratio of the upper kerf to lower kerf, and surface roughness) are considered as optimization criteria. Validating the theoretical results using the experimental tests is carried out in order to analyze the results obtained via software.