Investigation on performance of abrasive water jet in machining hybrid composites

For machining of composites, abrasive water jet machining is widely employed. For assembly of the machine tool structure, production of slots is essential. In this paper, abrasive water jet machining of composite laminates was experimentally investigated for various cutting parameters in terms of average surface roughness (R_a) and kerf taper (K_t). By generating a response surface model, the experimental values obtained for quality characteristics (R_a and K_t) were empirically related to cutting parameters. The effects of cutting parameters on quality characteristics were analyzed by utilizing empirical models and also optimized within the tested range based on desirability approach. The optimum parameter levels were also validated by confirmation test. From this investigation, it is evident that for obtaining a minimum kerf taper, traverse speed, water pressure, and abrasive mass flow rate are significant parameters and for obtaining less surface roughness traverse speed is the significant parameter.     

Machinability study of abrasive aqua jet parameters on hybrid metal matrix composite

The present work involves investigation of the abrasive aqua jet (AAJ) machining of hybrid metal matrix which consists of Al 6063 reinforced with boron carbide (B₄C) and zirconium silicate (ZrSiO₄) in the form of particulates in the proportion of 5% B₄C and 5% ZrSiO₄. The Response surface method using a central composite design was adopted for conducting experiments by changing the aqua jet pressure, abrasive flow rate, and traverse rate. The results were taken with different types of abrasives of various mesh sizes in this study, which were analyzed using response surface graphs. The striation effect on the bottom-machined surfaces was also examined using the striation length and its frequency. Surface topography and morphology were analyzed on the AAJ-machined composite kerf wall cut surfaces. The machined surface exhibited the inherent characteristics of AAJ which included wear tracks, and contamination generated in the metal surface. The experimental results revealed that higher abrasive flow rate (400 g/min), lower traverse rate (30 mm/min), and higher aqua jet pressure (300 MPa), the production of a higher material removal rate, lower surface roughness and kerf taper angle.     

Investigation of multiple process parameters in abrasive water jet machining of tiles

This paper discusses the optimization of an abrasive water jet machining process with multiple characteristics, using the Taguchi orthogonal array and grey relational analysis (GRA). The machining process variables, such as mesh size, nozzle diameter, abrasive flow rate, water pressure, stand-off distance, and feed rate, were optimized with respect to multiple performance characteristics, namely, the surface roughness and the kerf angle. Experiments were performed using an L₁₈ orthogonal array, and the optimum machining process variables were determined, using GRA. Analysis of variance was used to identify the most significant factor in the machining performance. A confirmatory test was performed to verify the improvement of the performance characteristics. The microstructure of the machined surfaces was also examined by scanning electron microscopy and atomic force microscopy. The results showed that the surface roughness and kerf angle were minimized under optimal machining conditions.     

Machinability of Nickel-Based Superalloy by Abrasive Water Jet Machining

This paper deals with the machinability of nickel-based superalloys using abrasive water jet machining process. The machining studies were carried out with three different parameters such as water jet pressure, traverse speed of jet nozzle, and standoff distance at three different levels. The performances of the process parameters are evaluated by measuring difference in kerf width, kerf wall inclination, and material removal rate (MRR). Further, the surface morphology and material removal mechanisms are analyzed through scanning electron microscope (SEM) images. It is found that water jet pressure is the most influencing factor related to surface morphology and surface quality.     

Machinablity of Hybrid Natural Fiber Composite with and without Filler as Reinforcement

The filler materials are reinforced along with natural fibers in the composite to improve the quality and property of the component materials based on the requirements and its applications. In this paper, hybrid natural fiber composites were developed with and without filler materials as reinforcement. The developed hybrid natural fiber composites are machined using abrasive water jet cutting process with three different cutting parameters. The influences of cutting parameters are evaluated with respect to the kerf wall inclination, material removal rate, and surface roughness. The surface morphology was also studied to infer the basic mechanism involved during composite machining. The hybrid fiber composite with filler has proved that it can produce good engineering component without delamination and fiber pullouts during machining.     

Surface integrity of Mg-based nanocomposite produced by Abrasive Water Jet Machining (AWJM)

This paper investigates the influence of jet traverse speed on the surface integrity of 0.66?wt% Al₂O₃ nanoparticle reinforced metal matrix composite (MMC) generated by Abrasive Water Jet Machining (AWJM). Surface morphology, surface topography, and surface roughness (SR) of the AWJ surface were analyzed. The machined surfaces of the nanocomposites were examined by laser confocal microscope and field emission scanning electron microscope (FESEM). Microhardness and elasticity modulus measurement by nanoindentation testing were also performed across thickness of the samples to see depth of the zone, affected by AWJ cutting. The result reveals that extent of grooving by abrasive particle and irregularity in AWJ machined surface increases as the traverse speed increased. Similarly, the rise in value of surface roughness parameters with traverse speed was also seen. In addition, nanoindentation testing represents the lower hardness and elastic modulus due to softening occurs in AWJ surface.     

Surface integrity studies on abrasive water jet cutting of AISI D2 steel

This article investigates the 3D surface topography and 2D roughness profiles, and micrographs were analyzed in the abrasive water jet (AWJ) cutting of AISI D2 steel kerf wall cut surfaces by varying water jet pressures and jet impact angles. In 3D surface topography, roughness parameters such as Sq, Ssk, Sp, Sv, Sku, Sz, and Sa were improved by various jet impact angles with different water jet pressures. However, the roughness parameters Ssk and Sku strongly depend on the water jet pressure and jet impact angle. This is confirmed by kerf wall cut profile structures. Fine irregularities of peaks and valleys are found on the AWJ cut surfaces, as evident from 2D roughness profiles. The scanning electron microscope micrographs confirm the production of an upper zone not very much damaged and a lower striation free bottom zone, by using the jet impact angle of 70° with a water jet pressure of 200?MPa. Finally, the results indicate a jet impact angle of 70° maintaining the surface integrity of D2 steel better than normal jet impact angle of 90°. The results are useful in mating applications subjected to wear and friction. This has resulted in enhancement of the functionality of the AWJ machined D2 steel components.     

Multiresponse Optimization of Abrasive Water Jet Cutting Process Parameters Using TOPSIS Approach

This paper describes how optimization studies were carried out on an abrasive water jet (AWJ) cutting process with multiresponse characteristics based on Multi Criteria Decision Making Methodology (MCDM) using the Technique for Order Preference by Similarity Ideal Solution (TOPSIS) approach. The process parameters water jet pressure, traverse rate, abrasive flow rate, and standoff distance are optimized with multiresponse characteristics, including the depth of penetration (DOP), cutting rate (CR), surface roughness (R_a), taper cut ratio (TCR), and top kerf width (TKW). The optimized results obtained from this approach indicate that higher DOP and CR and lower R_a, TCR, and TKW were achieved with combinations of the AWJ cutting process parameters, such as water jet pressure of 300 MPa, traverse rate of 120 mm/min, abrasive flow rate of 360 g/min, and standoff distance of 1 mm. The experimental results indicate that the multiresponse characteristics of the AA5083-H32 unit used during the AWJ cutting process can be enhanced through the TOPSIS method. Analysis of variance was carried out to determine the significant factors for the AWJ cutting process.     

Investigation of process parameters influence in abrasive water jet cutting of D2 steel

In the present experimental study, abrasive water jet (AWJ) cutting tests were conducted on D2 steel by different jet impingement angles and abrasive mesh sizes. The experimental data was statistically analyzed using the simos–grey relational method and ANOVA test. In addition, the outcome of influencing cutting parameters, namely jet pressure, jet impingement angle, and abrasive mesh size on the different response parameters, namely, the jet penetration, material removal rate, taper ratio, roughness, and topography, were studied. Micro-hardness test and surface morphology analysis were employed to examine the D2 cut surfaces at different AWJ cutting conditions. The chemical element study was performed to determine the abrasive particle contamination in the AWJ kerf wall cut surfaces. The ANOVA test result indicated the jet pressure and jet impingement angle as the influencing process parameters affecting the various performance characteristics of AWJ cutting. The overall AWJ cutting performance of the D2 steel has been improved through proper identification of the optimal process parameter settings, namely jet pressure 225?MPa, abrasive mesh size #100, and jet impingement angle 70° by the simos–grey relational analysis.     

Electrolytic concentration effect on the abrasive assisted-electrochemical machining of an aluminum–boron carbide composite

All engineering materials can be machined by one or combination of processes in such a way that the material’s potential is fully exploited. Electrochemical machining is found to be a most promising process that produces various components from the hard-to-machine materials for the various applications. Electrolyte concentration is playing a positive role by improving the electrolyte conductivity, but negatively forming the passivation layer on the cut surfaces. In order to improve the surface finish and removal of generated residual materials from the cut surfaces, abrasive particles were fed along with electrolyte into the machining zone. This present paper investigates the sodium chloride (NaCl) electrolyte with varied concentration (10–30%) in association with SiC abrasive particles on the material removal rate, surface roughness, and radial overcut while machining of aluminum 6061–boron carbide (5–15?wt%) composites. This study conclusively derived that electrolyte concentration up to 20% exhibited a positive role in the material removal rate for the machining of composites because the rate of dissolution was of higher magnitude. Externally supplied abrasive particles along with electrolyte reduced the surface roughness and radial over cut to an extent. Conversely, at higher electrolyte concentration, the externally supplied abrasive particles have a little effect on the removal of the formed passivation layer as confirmed by SEM analysis.     

Abrasive waterjet cutting of cladded material: kerf taper and MRR analysis

Gas/plasma cutting of cladded materials provides inferior cut quality that demands subsequent finishing processes. Abrasive waterjet cutting could be a proficient alternate in terms of cut quality. However, the inherent problem of kerf taper and low material removal rate in comparison to the said thermal cutting processes limit its application. Therefore, potential of aforesaid machining process for cutting of stainless-clad steel is investigated with a prior focus on maximizing the material removal rate with minimum kerf taper. Abrasive mass flow, traverse speed, water pressure, and stand-off distance have been selected as input parameters. ANOVA analysis revealed that traverse rate as well as abrasive mass flow are the major contributing factors for both the responses. Optimal settings of parameters developed by S/N ratio analysis results in an improvement of 18.6% in material removal rate and 39% in the kerf taper. Moreover, regression models are developed and validated through various statistical tests.     

An investigation on cutting quality by adding polymer in abrasive water jet

ABSTRACT

An experimental investigation is presented to improve the cutting quality in abrasive water jet (AWJ) cutting of marble by an addition of polyacrylamide (PAM). Considering experimental data, the kerf widths have a remarkable change when the PAM concentration approaches to 400 ppm. The deviation between top and bottom kerf width reaches the minimal value when PAM concentration is equal to about 600 ppm. In addition, the surface topography analyses illustrate that an addition of PAM can broaden the cutting wear zone and make the cutting quality better. Furthermore, the effects of PAM on the surface roughness are assessed by a profilometer. It is eventually found that the surface roughness decreases initially and then increases greatly with the increase of the depth of cut. Additionally, the minimum surface roughness occurs when the PAM concentration is 600 ppm, which agrees well with the experimental result of kerf width. An increasing stand-off distance or traverse speed produces a higher surface roughness.     

Effect of abrasive water jet machining parameters on aramid fibre reinforced plastics composite

This paper presents a study on the effect of abrasive water jet machining (AWJM) process parameters on surface roughness (R _a) and kerf taper ratio (T _R) of aramid fibre reinforced plastics (AFRP) composite. Taguchi’s design of experiment was used as the experimental approach. Through analysis of variance (ANOVA), it was found that the traverse rate was considered to be the most significant factor in both R _a and T _R quality criteria. R _a and T _R were reduced as increasing the hydraulic pressure and reducing the standoff distance and traverse rate. However, there was no clear pattern for abrasive mass flow rate on both R _a and T _R. Therefore, it was confirmed that increasing the kinetic energy of water jet may produce a better quality of cuts. Mathematical models were also developed using multiple linear regression analysis to predict the performance of R _a and T _R in terms of AWJM process parameters. Considerably, the models are useful in predicting R _a and T _R in AWJM of AFRP laminate as shown in present study.     

Study the parametric effect of abrasive water jet machining on surface roughness of Inconel 718 using RSM-BBD techniques

This paper presents an experimental investigation to ascertain the parametric impact of abrasive water jet machining on the surface quality of Inconel 718 material. Experiments were designed according to response surface methodology-box Behnken design by maintaining three levels of four process parameters—abrasive flow rate, water pressure, stand-off distance and traverse speed. The surface irregularity is measured during machining. The design expert software was used to establish an optimized mathematical model of process parameters for achieving the required surface roughness. Desirability function has also been used to optimize the process parameters. The confirmation experiments validate the reliability and capability of the developed model. Further, the surface characteristics were analyzed through scanning electron microscope images and energy-dispersive X-ray spectroscopy.     

Cutting performance of glass-vinyl ester composite by abrasive water jet

Polymer matrix composite materials have been increasingly used in aerospace, defense, automotive and marine industries. In these fields, nontraditional machining method of abrasive water jet (AWJ) has been used significantly in order to form polymer matrix components. In this study, glass fiber reinforced vinyl ester composite plates have been investigated under various AWJ cutting parameters by using the Taguchi experimental design in detail. For Taguchi experimental design, experimental parameters of standoff distance, abrasive mass flow rate, traverse speed, pressure and material thickness were determined at three levels. Top kerf width and the surface roughness were investigated in order to understand the cutting performance. Finally, linear regression models were conducted and all performance parameters were examined using analysis of variance (ANOVA) and main effects plots. According to the overall test results, standoff distance was determined as the most effective one. The optimal parameter levels were obtained by the ‘main effects plots’, and finally, the predictive modeling was validated by performing the optimal combination of parameter levels.     

AWJ machinability performance of CS/UPR composites with the effect of chemical treatment

This work focuses on the effect of chemical treatment of coconut sheath/unsaturated polyester (CS/UPR) composite on the performance of abrasive waterjet machining (AWJM). Two different chemical treatments, namely alkali (NaOH) and trichlorovinylsilane, were imposed on the CS fiber. Further, the induced compressive strength arising as a result of AWJM was studied along the radial and depth directions of the composite. Experimental results revealed significantly lower induced stress at all points compared to the ultimate stress of CS/UPR composites except the free-edge loading condition. The chemically treated composites also exhibited inconsistent results in the machining characteristics such as kerf taper angle (T_a) and surface roughness (R_a) under varying cutting conditions. However, no direct correlation was seen between interfacial adhesion and T_a and R_a of the cutting zone. The maximum decrease of 12% of T_a and 22% of R_a was found for silane-treated composites compared to the untreated ones. In addition, the composite failure mechanisms such as fiber pullout, fiber breakage, interfacial debonding, matrix failure, and voids were identified in the cutting surfaces through scanning electron microscopy analysis.     

旋转超声磨削Si3 N4陶瓷用金刚石磨具磨损行为研究

热压烧结Si₃N₄陶瓷材料常应用于航天飞行器中关键耐高温零部件,但由于高硬度和低断裂韧性,其加工效率和加工表面质量难以满足制造需求。为了提高热压烧结Si₃N₄陶瓷旋转超声磨削加工质量,减小由于金刚石磨具磨损带来的加工误差,开展了磨具磨损行为研究。基于热压烧结Si₃N₄陶瓷旋转超声磨削加工实验,分析了金刚石磨具磨损形式;基于回归分析建立了金刚石磨具磨损量数学模型,揭示了加工参数及磨具参数与金刚石磨具磨损量间映射关系;并研究了磨损形式与磨具磨损量及加工表面粗糙度影响规律。结果表明：磨粒磨耗是旋转超声磨削Si₃N₄陶瓷用金刚石磨具最主要磨损形式,比例超过50%;主轴转速和磨粒粒度对磨具磨损量影响最为显著;且磨损量较小时,加工表面粗糙度值反而增加。以上研究可为提高旋转超声磨削Si₃N₄陶瓷加工精度和加工质量提供指导。     

Turning of glass with abrasive waterjet

This article reports research results on abrasive waterjet (AWJ) turning of glass. Glass rods, 25 mm in diameter, were turned by using AWJ to investigate the effects of several process parameters on the surface quality of the machined glass surfaces. The parameters studied are rotational speed, stand-off distance, water pressure, nozzle traverse speed, and abrasive flow rate. The results were also compared with those obtained from conventional machining of glass. The results showed that higher traverse rates were associated with an increase in material removal rate and thus an increase in surface roughness and waviness values. The sensitivity of surface quality to rotational speed was more than that to the traverse speed. Good surface finish was achieved at lower traverse speeds and higher turning speeds. Higher stand-off produced rougher surface finish. The best finish was generated when the nozzle consumed 300 g min^-1 of abrasives. Higher pressures did not produce smoother surface finish.     

Study of trimming damages of CFRP structures in function of the machining processes and their impact on the mechanical behavior

The main focus of this paper is to investigate the defects generated by different machining processes (namely burr tool machining, abrasive water jet machining ‘AWJM’ and abrasive diamond cutter ‘ADS’) and their impact on the mechanical behavior of CFRP in quasi-static (compression and inter-laminar shear) and tensile–tensile fatigue tests. The cutting conditions are selected so that different levels of degradation can be obtained. The machined surface is characterized using roughness measuring devices with and without contact and SEM observations. The results show that the defects generated during the trimming process with a cutting tool are fibers pull-out and resin degradation. These defects are mainly located in the layers with the fibers oriented at −45° and 90°. However, when using abrasive water jet and abrasive diamond processes, the defects generated have the form of streaks and are not dependent on the fiber orientation. Furthermore, the results of quasi-static tests performed on specimens machined by cutting tools show that AWJ specimens offer a better resistance in compression but the ADS samples offer higher inter-laminar-shear strengths. Moreover, the results of fatigue tests show that specimens machined with a burr tool offer higher endurance limit. Finally, it is concluded that the type and the mode of the mechanical loading (quasi-static fatigue) affect the mechanical response of CFRP and favor a given machining process.     

Effect of abrasive jet process parameters on machining glass fibre reinforced polymer composite

An experimental and theoretical research work on abrasive jet machining of glass fiber reinforced polymer composite materials was conducted using abrasive jet machining setup fabricated in our workshop. The objective of this research work is to machine holes on the glass fiber reinforced polymer composite using an abrasive jet machine under various levels of process parameter. The material removal rate and hole geometry (kerf analysis) were observed as a part of the investigation. Four factors five levels central composite rotatable design matrix was used for optimizing the required number of experiments. The objective of the present investigation is to develop mathematical models using the response surface methodology. The adequacy of the models has been checked using the ANOVA technique. Use of the developed mathematical models, material removal rate and hole geometry of the machined glass fibre reinforced polymer composite helps prediction at 95% confidence level.