Abrasive Mass Flow Rate Research Articles

Focusing tube operational vibration as a means for monitoring the abrasive waterjet cutting capability

Abstract Abrasive waterjet cutting is a competitive manufacturing technology in the aerospace, defense and automotive industries which, as power users, require state of the art process performances in terms of stability and product assurance, due to their demanding quality standards. Meeting such requirements is a relevant technical challenge for abrasive waterjet cutting, due to insufficient monitored data and intrinsic process instability. The present paper describes an innovative approach based on non-invasive vibration sensors, for monitoring the jet cutting capability. This result is allowed by the experimental evidence proving that the operational vibration monitored by means of two accelerometers installed at the tip of the focusing tube is well related to the kinetic power of the abrasive particles, i.e. the only portion of the jet power that is responsible for the material removal in abrasive waterjet cutting. The approach is validated by means of an experimental investigation, in which the abrasive waterjet is fired at different water pressures and abrasive mass flow rates, providing different kinetic powers. The information delivered enriches the process knowledge, thus paving the way to significant improvements ranging from closed-loop control strategies for the water and abrasive feeding systems to actions for supporting operators in compensating drifts of the jet cutting capability. The expected impact is an improvement of process automation and stability, as well as an enhanced process traceability.

Analysis of the initial damage region in agate plates cut by abrasive waterjet (AWJ) process

The abrasive waterjet (AWJ) cutting process has been widely used in the gemstone processing industry due to its versatility and accuracy characteristics. The influence of the parameters involved in the AWJ process has been investigated by many authors, and it can be seen that in each application different responses are reported. In agate processing via AWJ, the final quality of the piece depends on the properties of the initial damage region (IDR), such as width and depth. The present study has purpose to investigate the influence of the standoff distance, traverse speed, working pressure, and abrasive mass flow rate on the depth and width of the IDR when cutting agates through AWJ. A set of 80 samples were analyzed, and the measurement of the depth and width of the IDR was performed through three-dimensional scanning using X-ray computed microtomography (XCM). This technique allows assessing the IDR in an accurate and reliable way. The results showed that, within the investigated range of parameters, the width and depth of the IDR vary between 0.3 and 0.7 mm. Also, the IDR in the agate plates is strongly influenced by the standoff distance.

Manufacturing and Optimization of Process Parameters by using Abrasive Water Jet Machining of Carbon Fibre Reinforced Polymer Composites

In the last decade, invention of new material is the point of interest of researchers. Carbon composite epoxy is one of those materials, which are currently used in transportation, aerospace, structural as well as naval applications. It is very difficult to machine those carbon composite materials using traditional methods, so an updated solution for this issue is machining using Abrasive Water Jet. Significant input parameters namely Standoff Distance, Abrasive Mass Flow Rate and Traverse Rate are varied for various outputs, out of which kerf width is main point of focus. For précised values, Kerf Width measurement is carried out using Profile Projector. The process parameters were further optimized using GRA and Taguchi method. Regression models were developed for correlation with actual generated data using experiments. The result obtained using Optimization technique and Taguchi method is confirmed using confirmation experiment. The parameters were optimized for Kerf Width of carbon fibre with reference to input parameters by using AWJM.

Effect of Delamination in Carbon Fibre Reinforced Polymer during Abrasive Water Jet Machining

Delamination is a type of defect produced while machining composites or layered materials. Due to matrix crack, shear crack and bending crack delamination is caused. Delamination is usually a separation along a plane parallel to the surface as in the separation of a coating from a substrate or layers of coating from each other. The aim of this project is to explore the study of delamination in carbon Fibre/epoxy composites under abrasive water jet machining. An experimental investigation was held to study the effect of delamination due to abrasive water jet machining on carbon fibre reinforced polymer. Effect of various parameters such as transverse speed, standoff distance, abrasive mass flow rate and water pressure was analysed. Taguchi method was used for overall analysis of parameters. Effect of Kerf width in CFRP material and on fibre cut was analysed step by step. Further observation was done on scanning electron microscopes. It can affect the compression strength of composite laminate and it will slowly cause the composite to experience failure through the buckling. Here the composite of Carbon Fibre Reinforced Polymer is made using carbon fibers and epoxy resin. Further cutting of CFRP is done using Abrasive water jet machining and analysis of delamination at various phases of the material is done. Analysis is done at which parameters delamination is reduced to minimum.

An investigation on machining characteristics in abrasive water jet machining of hybrid laminated composites with SiC nano particles

Abrasive Water Jet Machining process is widely employed in the machining of composite materials. In this work, a novel combination of hybrid laminated composite materials is developed, with Carbon and S-Glass fibers as primary reinforcement and filler material as SiC nano particles. An experimental investigation were conducted to assess the influence of abrasive water jet machining process parameters on kerf taper (Kt) and average surface roughness (Ra) of laminated hybrid composites. The effects of process parameters on experimentally obtained quality characteristics (Ra and Kt) values were empirically correlated by generating response surface graphs and also optimized within the tested range based on desirability approach. The optimal combination process parameters are traverse speed of 145 mm/min, abrasive mass flow rate of 115 g/min, water pressure of 200 MPa and stand-off distance of 1 mm. The optimum parameter levels were also confirmed by verification test. It is clear that, for obtaining a better quality characteristics abrasive mass flow rate and water pressure are significant parameters. The machined surfaces were examined with a Scanning Electron Microscope (SEM) to observe the quality of machined composite surface with the optimal settings obtained through response surface method.

Grey-fuzzy method-based parametric analysis of abrasive water jet machining on GFRP composites

Abrasive water jet machining (AWJM) is an advanced non-traditional material removal process which can machine almost all types of thin hard-to-cut materials. The quality of its machining operation can be effectively enhanced while selecting the appropriate settings of its different input parameters through the application of optimization techniques. This paper aims in obtaining the optimal combination of four AWJM control parameters, such as water jet pressure, stand-off distance, abrasive mass flow rate and traverse speed while machining of glass fiber reinforced polymer (GFRP) composites. Grey relational analysis combined with fuzzy logic is employed here for attaining the most favored values of the process outputs (responses), i.e. material removal rate, surface roughness, kerf width and kerf angle. The effects of varying AWJM process parameters on the measured responses are further studied through the developed interaction plots, while the contributions of those process parameters are identified through analysis of variance technique. The response surface plots would further help in determining the attainable values of the corresponding process parameters to realize the desired quality of the considered responses.

Experiment on carbon fiber–reinforced plastic cutting by abrasive waterjet with specific emphasis on surface morphology

In the machining of carbon fiber–reinforced plastic by abrasive waterjet, the surface morphology of the cutting front directly reflects the processing quality. So in this study, the changes in the topography and surface roughness of the cutting front as a result of variations in five operational parameters, namely, the traverse speed, abrasive mass flow rate, waterjet pressure, standoff distance, and sample thickness, were experimentally studied with the aid of μscan laser confocal microscopy. It was found that periodic stripes and grooves appeared in the traverse direction from observations of three-dimensional surface morphology. And the analysis of the surface roughness revealed that there were three distinct cutting regions along the penetration direction, namely, an initial damage region at the jet entry, a smooth cutting region in the intervening cutting area, and a rough cutting region near the jet exit. According to the three distinct regions in the penetration direction, a three-zone cutting front model was proposed. A high-quality machined surface could be obtained by extending the smooth cutting zone through the appropriate choice of process parameters. Therefore, the influences of the above five parameters on the length of the smooth cutting zone were also investigated, and recommendations are proposed for process control.

Multi-Objective Optimization of Abrasive Water Jet Cutting Using MOGA

Abrasive water jet (AWJ) cutting is an unconventional machining process used to cut different types and thicknesses of materials. Cutting process is based on material removal by erosion. Cutting tool is an ultra-fast thin jet of water mixed with abrasive particles. High-speed water jet accelerates the abrasive particles and these particles erode the material. AWJ cutting is a complex process with many factors that determine performances. The most important factors are: water pressure, water flow rate, orifice diameter, nozzle diameter, abrasive mass flow rate, traverse speed and standoff distance. The most important performances are performances related to economy, productivity and quality. Optimizing the AWJ cutting performances is essential in order to obtain better product quality, higher productivity and higher economic efficiency. In process optimization it is logical to take economy and productivity performances as objectives and quality performances as constraints. For the realization of production goal single-objective optimization is a good way, but multi-objective optimization is the right way. In this paper, multi-objective optimization of abrasive water jet cutting carbon steel S235 is studied. Optimization was performed to simultaneously optimize two objectives (productivity and operating cost) with three factors (traverse speed, abrasive mass flow rate and standoff distance) and three constraints (perpendicularity tolerance, surface roughness limit and traverse speed for separation cut). The optimization problem was solved using multi-objective genetic algorithm (MOGA).

Determination of the Correlation between Process Parameters and Kerf Characteristics in Abrasive Waterjet Milling of High Strength 7075-T6 Aluminum Alloy

Non-conventional manufacturing processes are often advantageous compared to conventional ones, as they can achieve high productivity in demanding cases. Abrasive waterjet (AWJ) machining is one of the most established non-conventional machining processes, which can achieve high material removal rates without leading to undesired workpiece material alterations and can render a large variety of shapes. In the present work, experiments regarding the AWJ milling of high strength 7075-T6 aluminum alloy are conducted with a view to correlate the process parameters, such as waterjet pressure, jet standoff distance, jet traverse speed and abrasive mass flow rate with depth of penetration, width and taper angle of the produced kerf. After the correlation between input and output parameters of the process is established, statistical analysis enables the determination of the influence of input parameters on output quantities and finally, appropriate process conditions for the regulation of depth of cut and kerf characteristics are derived.

Experimental Analysis and Soft Computing Modeling of Abrasive Waterjet Milling of Steel Workpieces

Conventional machining processes such as turning, milling and drilling have long been prominent in the metalworking industry but alternative processes which do not require the use of a cutting tool in order to conduct material removal have also been proven to be sufficiently capable of achieving high efficiency in various cases. In particular, Abrasive Waterjet (AWJ) machining can be regarded as a rather appropriate choice for cutting operations, taking into consideration that it involves no heat affected zones, is able to process all material types and create a variety of complex features with success. In the present work, a comprehensive study on the effect of four process parameters, namely jet traverse speed, stand-off distance, abrasive mass flow rate and jet pressure on the width and depth of machined slots on a steel workpiece is conducted. The results are first analyzed with statistical methods in order to determine the effect and the relative importance of each parameter on the produced width and depth of the slots. Finally, these results are used to develop soft computing predictive models based on Artificial Neural Networks (ANN), which can efficiently relate the process parameters with its outcome.

Influence of abrasive water jet cutting on glass fibre reinforced polymer (GFRP) composites

Abrasive water jet cutting is an advanced machining process where the material is removed by the erosion of rough abrasive particles mixed high pressure of water jet velocity for hard metals and composite materials. In this study, the cutting of glass fiber reinforced polymer is carried out where the machining parameters are stand-off distance, water jet pressure, abrasive mass flow rate and traverse rate are considered for the machining operation. The outcomes of the experiment are material removal rate, kerf width and kerf taper angle. The graphs are plotted between the machining parameters and the outcomes, to study the significant, parameters for the better machining of the composite materials.

Surface morphology investigation of miniature gears manufactured by abrasive water jet machining

In this paper, surface morphology investigation of miniature spur gears manufactured by abrasive water jet machining is discussed. Water jet pressure, abrasive flow rate and stand-off-distance are the varying input parameters to study the surface morphology (surface roughness and topography) of the machined gears. From the investigation, the water jet pressure has highly influenced (with 47% contribution) the surface quality and found as a predominant process parameter. SEM micrograph study found that wear scars and clinging effects are the major surface defects found over the machined surfaces of the gear teeth. Maximum and minimum peaks of the wear tracks are observed with white light spectroscope. The best surface morphology with average surface roughness value 1.08 μm was achieved at 350 MPa water jet pressure, 225 g/min abrasive mass flow rate, and 1mm stand-off distance. The present work identifies the potential of AWJM process for manufacturing of high quality miniature gears.

Investigation and optimization for depth of cut and surface roughness for control depth milling in Titanium Ti6AL4V with abrasive water jet cutting

Abrasive water jet (AWJ) cutting has been widely used in industries because of its precise cutting technique. However, the effectiveness of AWJ cutting is dependent on machine operating parameters and the material properties. In this research AWJ cutting was applied on Titanium Ti6AL4V Grade 5 material to investigate the effects on depth of cut (DoC) and roughness. Taguchi L27 experiments were conducted at three levels with operating parameters such as water pressure, transverse speed, abrasive mass flow rate, abrasive orifice size; a novel approach of ratio 3:1 was adopted with nozzle and orifice diameter to accommodate more parameters for investigation and to inspect the variation of these parameters in real time. Minitab 2017 software was used to simulate the influencing parameters with ANOVA. (GRA) Grey relational analysis linked with Taguchi technique represents a novel approach to optimization. It is a normalization estimation technique extended to elucidate the complex multi-performance characteristics. GRA is used for optimizing the process parameter which helped in determining the optimal parameters for roughness and depth of cut, ANOVA was used for analyzing the effect of independent variables on dependent variables, as per ANOVA the P values and the S/N ration rank indicated that water pressure was the most influencing parameter for surface roughness and transverse speed was the most influencing parameter for the depth of cut. The prediction of cutting depth through GRA optimization proved a valuable tool for the controlled depth milling (CDM) in Ti6Al4V material.

Development of a predictive model for kerf taper angle in AWJM of Kevlar epoxy composite

This paper describes the research work involved in studying the influence of process parameters on kerf taper and development of predicative model for the response in abrasive water jet machining (AWJM) of Kevlar epoxy composite. Four process parameters namely water pressure, stand-off distance, traverse speed and abrasive mass flow rate are considered. To investigate the influence of process parameters on kerf taper, experiments are designed using response surface methodology. Experiments are conducted on flying arm AWJM setup. Kerf taper of machined work pieces is measured using vision measurement system. It is found that water pressure and traverse speed are most significant process parameters influencing kerf taper angle. Based on the analysis, a predictive model is developed to predict kerf taper angle. The confirmation tests are performed to verify the predicative model. The findings of present work is useful in minimizing the kerf taper during AWJM of composite materials.

Experimental study on abrasive water jet machining of carbon epoxy composite

ABSTRACTCarbon epoxy composite material is widely used in various technological applications. Traditional machining of this material is difficult. This paper presents research work involved in abrasive water jet machining of carbon epoxy composite material. Four process parameters, namely pressure, traverse rate, stand-off distance and abrasive mass flow rate, are considered for this study. Response surface methodology is used to design the experiments. Effect of process parameters on surface roughness is investigated on the basis of analysis of variance. Surface roughness decreases with an increase in pressure and abrasive mass flow rate and a decrease in stand-off distance and traverse rate. A mathematical model is developed to predict surface roughness on the basis of analysis. Defects including delamination, fibre pull-out and abrasive embedment are examined in machined samples. Further, optimisation of process parameters is performed in order to minimise surface roughness. Confirmation experiments are performed to verify the predictive model and optimise set of process parameters.

Defect Analysis and Detection of Cutting Regions in CFRP Machining Using AWJM.

The use of composite materials with a polymeric matrix, concretely carbon fiber reinforced polymer, is undergoing further development owing to the maturity reached by the forming processes and their excellent relationship in terms of specific properties. This means that they can be implemented more easily in different industrial sectors at a lower cost. However, when the components manufactured demand high dimensional and geometric requirements, they must be subjected to machining processes that cause damage to the material. As a result, alternative methods to conventional machining are increasingly being proposed. In this article, the abrasive waterjet machining process is proposed because of its advantages in terms of high production rates, absence of thermal damage and respect for the environment. In this way, it was possible to select parameters (stand-off distance, traverse feed rate, and abrasive mass flow rate) that minimize the characteristic defects of the process such as taper angle or the identification of different surface quality regions in order to eliminate striations caused by jet deviation. For this purpose, taper angle and roughness evaluations were carried out in three different zones: initial or jet inlet, intermediate, and final or jet outlet. In this way, it was possible to characterize different cutting regions with scanning electronic microscopy (SEM) and to distinguish the statistical significance of the parameters and their effects on the cut through an analysis of variance (ANOVA). This analysis has made it possible to distinguish the optimal parameters for the process.

Effect of Process Parameters on Depth of Penetration & Surface Roughness in Abrasive Waterjet Cutting of Copper

This study evaluates the effect of process parameters on depth of penetration and surface roughness in abrasive waterjet (AWJ) cutting of copper. Full factorial experiments are carried out on trapezoidal blocks for each of the three abrasive particle sizes used. Experimental parameters - abrasive mass flow rate, water jet pressure and traverse speed are varied at three levels. Main effects and contributions of process parameters to depth of penetration and surface roughness is calculated. From the data, it is observed that, high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in higher depth of penetration and a high abrasive mass flow rate, high water jet pressure and low traverse speed resulted in lesser Ravalue. Using experimental data a statistical model for predicting depth of penetration & surface roughness is developed. Error between experimental and statistical values are compared to validate the statistical model. The maximum DOP of 49.32mm was observed at AMFR=405.4 g/min, P=300 MPa, TS=60 mm/min, MS=60 Mesh and minimum DOP of 4.27mm was observed at AMFR=200 g/min, P=100 MPa, TS=90 mm/min, MS=80 Mesh.

Predication of Kerf Width and Surface Roughness in Waterjet Cutting using Neural Networks

Abrasive waterjet cutting is one of the unconventional methods used to cut some of the difficult to cut materials. In certain materials this method has proved to give better results compared to the conventional methods. In this model the water jet cutting is done on hastelloy using the three parameters which are abrasive mass flow rate, traverse speed, and the stand-off distance. The mathematical modelling to predict the kerf width based on these three input parameters is discussed in this paper. As the relation between the input and the output parameter is non-linear in nature neural network back propagation algorithm is used for the prediction. Here the experiment is conducted using waterjet cutting machine and the data’s like surface roughness, metal removal rate, kerf width and the kerf angle data are collected. Both the input and the output parameters are fed to the neural network toolbox programmed in the MATLAB. After 1000 iterations it has been found that the prediction is closer to the actual value. The mathematical constants which is the weight matrix is used to test the new set of data for accuracy. It has been found that the prediction is more accurate compared to the conventional methods. This experiment is based Taguch’s design which uses the above three parameters to cut the material. This paper also discusses on the predication of surface roughness of hastelloy created due to the variation in these parameters.

Fabrication of high aspect ratio free-standing structures using abrasive water jet micro-machining

The abrasive water jet micro-machining of high aspect ratio free-standing structures such as fins used in heat sinks was investigated. The aim was to fabricate the maximum number of fins per unit length with the highest aspect ratio into Al6061-T6, in order to maximize heat transfer potential. Adjacent straight channels at various offsets were machined using a micro-nozzle, thus leaving the free-standing structures in between. The effect of varying nozzle traverse speed, number of passes, water jet pressure, channel offset, and abrasive mass flow rate on the quality of the resulting free-standing structures was studied. Under some conditions, an undesirable ‘leveling’ phenomenon was found to occur, i.e. the tops of the free-standing structures eroded due to particle impacts at the periphery of the jet, and secondary slurry flow from within the channels between the structures. In general, conditions that led to a higher erosion rate (higher water jet pressures, lower nozzle traverse speeds, and higher abrasive mass flow rates) were found to minimize the leveling at a given offset, because the channels between the structures rapidly became deep, and secondary slurry flow was directed along the channel, rather than up the sidewalls. A threshold minimum offset to avoid this phenomenon was also determined. Contrary to previously reported results, it was found that the jet had ample energy to erode the target material even at effective stand-off distances (distance between nozzle and channel bottom) greater than 10 mm, provided that sufficiently large abrasive particles are used. With these factors in mind, it was demonstrated that high-quality free-standing structures with aspect ratios of more than 40 could be fabricated.

EXPERIMENTAL STUDY OF ABRASIVE WATER JET MACHINING OF KEVLAR EPOXY COMPOSITE

The present paper describes an experimental study of abrasive water jet machining (AWJM) of Kevlar epoxy composite. Influence of process parameters namely stand-off distance, water pressure, traverse speed and abrasive mass flow rate on surface roughness and kerf taper is investigated. Taguchi orthogonal approach is applied to plan the design of experiments; and subsequent analysis of experimental data is done using analysis of variance (ANOVA). It is found that water pressure and traverse speed are most significant parameters followed by stand-off distance and abrasive mass flow rate influencing surface roughness and kerf taper. With increase in water pressure and decrease in traverse speed, kerf taper and surface roughness decreases.