THE INFLUENCE OF ABRASIVE WATER JET MACHINING PARAMETERS .

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Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015ISSN 2278 – 0149 www.ijmerr.comVol. 4, No. 1, January 2015 2015 IJMERR. All Rights ReservedReview ArticleTHE INFLUENCE OF ABRASIVE WATER JETMACHINING PARAMETERS ON VARIOUSRESPONSES—A REVIEWJignesh K Patel1 and Abdulhafiz A Shaikh1**Corresponding Author: Abdulhafiz A Shaikh, aas@med.svnit.ac.inComposites materials are getting difficult to machine owing to its constituents properties, fiberorientation and relative volume fraction of matrix. Abrasive water jet machining is a recent nontraditional machining process, and widely used in many industrial applications. Abrasive waterjet cutting of material involves the effect of a high pressure velocity jet of water with inducedabrasive particle on to materials to be cut. The present paper collects the findings on influencesof distinct parameters of AWJ machining of composite materials. The parameters such ashydraulic pressure, traverse speed, abrasive mass flow rate, standoff distance, types of abrasivematerials, grit size, jet nozzle oscillation and cutting orientation are focused for kerf tapper angle,surface roughness and depth of cut. From the literature survey it was found that by increase ofwater pressure, kerf tapper angle and surface roughness gets decreased. However, traversespeed and standoff distance shows reverse effects.Keywords: Abrasive water jet machining, Kerf tapper ratio, Surface roughness, Fiberreinforced composite materials, Abrasive materialsINTRODUCTIONinstalled at Alton Boxboard in 1972 and ledto the development of a new tool formanufacturing industry (Walstad andNoecker, 1972). In the AWJ machiningprocess, high pressure water is supplied bya pump at the orifice inside the cutting headfrom where it is converted into a high velocityjet. While passing through a mixing chamber,water creates a vacuum which draws theabrasive particles into a focusing tube wherethe Abrasive Water Jet (AWJ) mixture isNature has taught that even the hardest rockscan be eroded by a stream of water andmoved away from the area. Because thiseffect could be seen, it could also be adaptedto man’s use. In the late 1960s Franz foundthat very high pressure jets could be used tocut through wood products with little damageto the material on the outside of the cutsurface and at relatively high cutting speed(Byran, 1963). The first equipment was1Department of Mechanical Engineering, SV National Institute of Technology, Ichchhanath, Surat 395007, Gujarat, India.383

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015formed (Momber, 1998). The jet plume(mixture of abrasives and water droplets)impacts the target surface it results in thegeneration of a unique footprint (kerf). As aresult of this, the work-piece material removalis mainly caused by the impact of amultitudeof high velocities abrasive particles asdiscussed by Momber and Kovacevic (1998).It has advantage over other machiningprocess; such as (a) it can cut any materiallike titanium, diamond, glass, plastics andcomposite, etc. (b) Any 2-D profile can cutwith high tolerance. (c) There is no directcontact between cutting tool and workmaterial, so no heat generation, no wear oftool and no structural change in work material.(d) No special fixture or tooling is requiredfor cutting. (e) It has minimum cutting force injet direction so no special clamping isrequired.generating system. (3) Cutting head and (4)Abrasive delivery system and catcher asshown in Figure 1.The Water Purifying and StorageSystemThe water purifying and storage system is usedfor supplying pressure to ultrahigh pressurepump continuously. Typical AWJ systemincludes two different storage tanks (i) cuttingtank, and (ii) cooling water tank as shown inFigure 1. Generally, particle having size greaterthan 1 µm needs to be removed from the wateras it creates wear of the critical part of pump,which leads to failure of pump. Cooling wateris used to reduce the temperature of oil pump.High Pressure Generating SystemThis system is equipped with intensifier andaccumulator to generate high pressure andstorage of high pressure water respectively.Intensifier includes double acting reciprocatingpump which is operated by oil pressure. Ultrahigh pressure pump includes two differentA typical abrasive water jet system includesmain four components: (1) the water purifyingand storage system. (2) High pressureFigure 1: Schematic Diagram of an Abrasive Water Jet Cutting System384

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015circuits to generate high pressure up to 600MPa. Accumulator stores the high pressurewater energy to reduce the pressure loss innext stage.which contains large amount of energy neededto absorb before it can damage any part.Catcher is used to collect the pressurizedwater after cutting.Cutting HeadLITERATURE OVERVIEWThe cutting head equipped with focusing tube,orifice, nozzle and mixing chamber. Generally,focusing tube is made up of stainless steelhaving length of 76.2 mm and diameter 0.76mm. Sapphire, ruby and diamond material canbe used for orifice having diameter rangingfrom 0.08 to 0.8 mm. High pressure tubecarries the pressured water from accumulatorto cutting head through focusing tube. Highpressure water passes through orifice whichconverts pressure energy of water into kineticenergy of water particle due to convergentshape of orifice. The high speed water jet thenpasses through a mixing chamber, which isdirectly connected to orifice. Water loses itspressure energy as it passes through mixingchamber due to venturi effect which createsvacuum in mixing chamber. Due to vacuumabrasive enters in mixing chamber mixes withwater. In mixing chamber high energy of waterparticle transfers to abrasive particle then mixerof water and abrasive pass through nozzle withact as saw to cut the material.Abrasive Water Jet Machining (AWJM) is anew non-conventional material removaltechnology which is increasingly used inindustry (Ciglar et al., 2009). The AWJMprocess has a high-potential and is applicableto both metals and non-metals (Jain, 2008).Thus, AWJM offers a productive alternative toconventional techniques. In AWJM processmaterial removal occurs through erosion andresults from the interaction between anabrasive laden water jet and target (Arola andRamulu, 1997). In this section an extensivereview of the current state of research anddevelopment in AWJM conducted. AWJ cuttinginvolves a large number of variables, andvirtually all these variables affect the cuttingresults, only the major and easy-to-adjustvariables were considered. The performanceof AWJM depends upon number of processparameters and can be classified into twocategories: the input parameters and outputparameters. The abrasive water jet machiningprocess is characterized by large number ofprocess parameters that determine efficiency,economy and quality of the whole process.Figure 2 demonstrates the factors influencingAWJ machining process.Abrasive Delivery System andCatcherThe abrasive delivery system includesabrasive hopper and pneumatically operatedvalve to control the abrasive mass flow rate.Generally, three different types of abrasivematerial used in industries such as garnet,aluminum oxide and silicon carbide withdifferent mesh size ranging from 60 to 120mesh. The target material is being cut by water,Shanmugam and Masood (2009) havemade an investigation on the kerf taper angle,generated by Abrasive Water Jet (AWJ)machining of two kinds of composite materials(i) epoxy pre-impregnated graphite wovenfabric and (ii) glass epoxy. The experiments385

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015Figure 2: Process Parameters Influencing the AWJ Machininghave been conducted on a flow water jetsystem with sapphire orifice having diameterof 0.254 mm and abrasive garnets with a meshsize of #80. Taguchi experiments design wasused to construct the design of experimentsfor the process parameters. Effect of differentfour process parameters were studied namelywater pressure, traverse speed, standoffdistance and abrasive mass flow rate on kerftaper angle. They concluded that, increase ofwater pressure and traverse speed shows theopposite effect on kerf taper angles as shownin Figures 3a and 6a. With increasing standoffdistance the kerf taper angle increases asdemonstrated in Figure 9a. As increase inabrasive mass flow rate kerf taper angle isdecreases insignificantly as illustrated inFigure 11a.Wang (1999) investigated the machinabilityand kerf characteristics of polymer matrixcomposite sheets under abrasive water jetmachining. Experiments were conducted ona Flow Systems International water jet cutterequipped with a model 20X dual intensifierhigh output pump (up to 380 MPa) and a fiveaxis robot positioning system to cut 300 x 300mm test specimens. The specimens wereprepared from Teflon and phenolic resin. Threemajor parameters have been studied mainly,water pressure, the nozzle traverse speed andthe standoff distance. It can be noted fromFigure 3b that both the top and bottom kerfwidths increase approximately linearly with thewater pressure. The kerf taper angle alsoincreases with the water pressure. The effectof traverse speed on the top kerf width, bottom386

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015kerf width and kerf taper is shown in Figure6b. As shown in Figure 9b, that the top andbottom kerf widths increase with an increasein the standoff distance.model water jet, driven by a Model 20-35 waterjet pump. The material used for theexperiments was graphite/epoxy (Gr/Ep)laminated sheets with 16 mm thickness. Threeseries of cutting tests were performed eachconstructed using a Taguchi’s experimentaldesign array. Five independent variablesassociated with AWJ cutting process werevaried including jet pressure, standoff distance,traverse speed, grit size and abrasive massflow rate. Surface roughness parametersincluding Ra, Rq, Ry, and Rz were obtained withSurfAnalyzer 4000 profilometer using a 5µdiameter probe. Measurements were reducedusing analysis of variance (ANOVA)techniques of Taguchi to designate the effectsand interaction effects of the processparameters on cut quality. Kerf taper (TR) wasdefined as the ratio of the jet entrance kerfwidth to th exit kerf width. Taper (T R )measurements were obtained by recordingthe entrance and exit kerf widths an opticalmicroscope and calculating the ratio of themeasurements.Azmir and Ahsan (2009) explained theinfluence of six machining parameters onsurface roughness (Ra) and kerf taper ratio(TR) characteristics during an abrasive waterjet machining of glass/epoxy laminatedcomposite. Taguchi’s design of experimentsand analysis of variance were used todetermine the effect of machining parameterson Ra and TR. In this case, six machiningparameters abrasive types, hydraulicpressure, standoff distance, abrasive massflow rate, traverse rate and cutting orientationwere selected as control factors. Theequipment used for machining the sampleswas Excel-CNC abrasive water jet cuttingmachine equipped with Ingersold Rand modelof water jet pump with the designed pressureof 345 MPa. The machine is equipped with agravity feed type of abrasive hopper, anabrasive feeder system. For the nozzleassembly, it has an orifice of 0.25 mmdiameter of sapphire jewel and a focusing tubeof 0.76 mm internal diameter of carbide with afocus length of 70 mm. The effect of hydraulicpressure, traverse speed, standoff distance,abrasive mass flow rate, types of abrasive andcutting orientation on mean kerf taper ratio andmean surface roughness as shown in Figures3c, 6c, 9c, 12b, 14a,15a and 4a, 7a, 10a, 13a,14a and 15a respectively.Azmir et al. (2009) investigated the effectof Abrasive Water Jet Machining (AWJM)process parameters on kerf taper ratio (T R)and surface roughness (Ra) of Aramid FiberReinforced Plastics (AFRP) composite.Taguchi’s design of experiment was used asthe experimental approach. The equipmentused for machining the samples was ExcelCNC abrasive water jet cutting machineequipped with Ingersold Rand model of waterjet pump with a designed pressure of 345MPa. In that study, Kevlar 129 was used andhand laminated in the prepreg form ofmodified phenolic resin having its realweight of 410 g/m2. The aramid fibres whichRamulu and Arola (1994) examined theinfluence of cutting parameters on the surfaceroughness and kerf taper of an abrasive waterjet machined graphite/epoxy laminate. All theexperiments were performed with a PowerJet387

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015was readily available in a woven fabric andnamed for its manufacture’s style of 258 (2 2 basket weave) were used for thepreparation of the laminates Throughanalysis of variance (ANOVA), it was foundthat the traverse rate was considered to bethe most significant factor in both TR and Raquality criteria. TR and Ra were reduced asincreasing the hydraulic pressure as shownin Figures 3e and 4b. T R and R a wereincreases as the traverse rate and standoffdistance increases, as demonstrated inFigures 6e, 7b, 9d and 10b respectively.However, there was no clear pattern forabrasive mass flow rate on both Ra and TRas shown in Figures 12c and 13b.rate shows the opposite effect on depth ofpenetration as given in Figure 8.Xu and Wang have been presented anddiscussed an experimental investigation ofAbrasive Water Jet (AWJ) cutting of aluminaceramics with controlled nozzle oscillation. Inthat experiment, the specimens used were87% alumina ceramic plates with a thicknessof 12.7 mm, to represent brittle materials. Theabrasive water jet cutting system employedwas the Flow International Water jet Cutterdriven by a “Model 20X” dual intensifierpumping system, with an operating pressureof up to 380 MPa. A Taguchi experimentaldesign array was used to construct the cuttingtests. They found that, larger oscillation anglesincrease the overlap cutting action and thenumber of scanning actions on a given part ofsurface, so that the scanning action wasdominant and thus reduces the surfaceroughness. It has been found that oscillationangle have a similar effect on kerf taper andsurface roughness.Wang and Guo (2002) developed semiempirical model to predict the depth of jetpenetration in abrasive water jet cutting ofpolymer matrix composites. All theexperiments have been conducted on a FlowSystems International water jet cutter to cut 300X 300 mm2 test specimens of 16 mm thick.The water jet cutter was equipped with a model20X dual intensifier high output pump (up to380 MPa) and a five-axis robot manipulatorfor positioning and moving the nozzle. All thespecimens were Phenolic Fabric PolymerMatrix Composites which are non-metalliclaminated sheets made by impregnated layersof fiber (cotton) reinforcement with resin matrix.They have studied the effect of threeparameters likely, water pressure, nozzletraverse speed, and abrasive mass flow rateon depth penetration while kept all otherparameters as constant. As shown in Figure 5and Figure 11, depth of penetration isincreases as water pressure and abrasivemass flow rate increases. While jet traverseHydraulic PressureEffect of Hydraulic Pressure onKerf GeometryShanmugam and Masood have been madean investigation on AWJ machining of graphitewoven fabric and glass epoxy and studied theinfluence of hydraulic pressure on kerfgeometry. Figure 3a shows the influence ofwater pressure on the kerf taper angles. Theyconcluded that, within the operating rangeselected, increase of water pressure resultsin decrease of kerf taper angles. When waterpressure is increased, the jet kinetic energyincreases that lead to a high momentumtransfer of the abrasive particles, generatinga wider-bottom kerf. Therefore, the difference388

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015in top and bottom kerf width is reduced,leading to a decrease in kerf taper angle.above are opposite to those reported in glass/epoxy cutting. This may stem from the differenttypes of materials processed, different pressureand speed ranges selected as well as differentratios of jet energy used to the energy requiredto cut the materials.Jun Wang studied the effect of hydraulicpressure on kerf taper angle on AWJ machiningof polymer matrix composite. As shown in Figure3b that both the top and bottom kerf widthsincrease approximately linearly with the waterpressure, as higher water pressure results ingreater jet kinetic energy impinging onto thematerial and opens a wider slot. The kerf taperangle also increases with the water pressure.This is because the bottom kerf width is notincreased in the same order as the top kerf width,as indicated in the figure. It follows that as the jetloses its kinetic energy, it cannot remove thematerial adequately at the lower section, resultingin a narrow bottom kerf. It is interesting to notethat the characteristics of the taper angle in termsof water pressure and traverse speed discussedAzmir and Ahsan have been made aninvestigation on AWJ machining glass/epoxyand studied the influence of hydraulic pressureon kerf geometry. Higher hydraulic pressureresults in greater jet kinetic energy and opensa wider slot on the work-piece on both of thetop and bottom widths. Consequently, the kerftaper ratio calculated as the ratio of top to thebottom width is reduced with further increaseof supply hydraulic pressure due to the morerapidly increasing of top kerf width comparedto the bottom kerf width. This is clearlyillustrated in Figure 3c.Figure 3: Effect of Hydraulic Pressure on Kerf Taper Ratio389

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015Effect of Hydraulic Pressure onSurface RoughnessRamulu and Arola studied the effect ofhydraulic pressure on kerf taper ratio of AWJmachining of graphite/epoxy laminatedcomposite. The influence of pressure on kerftaper is shown in Figure 3d. High supplypressures increase the kinetic energy of theabrasive particles and retain their capacity formaterial removal. As expected, higher supplypressures reduce the kerf taper over the cuttingdepth. Further increases in the supply pressurewould reduce the kerf taper.Azmir and Ahsan studied the effect ofhydraulic pressure on surface roughness ofAWJ machining of glass/epoxy laminatedcomposite. While, in case of hydraulicpressure, a higher hydraulic pressureincreases the kinetic energy of the abrasiveparticles and enhances their capability formaterial removal. As a result, the surfaceroughness decreases as illustrated inFigure 4a.Azmir et al. have been made aninvestigation on AWJ machining aramid fiberreinforced plastics and studied the influenceof hydraulic pressure on kerf geometry. Higherhydraulic pressure results in greater jet kineticenergy and opens a wider slot on the workpiece on both of the top and bottom widths. TRis reduced with further increase of supplyhydraulic pressure due to the more rapidlyincreasing of top kerf width compared to thebottom kerf width. This is clearly illustrated inFigure 3e.Azmir et al. have been made aninvestigation on AWJ machining aramid fiberreinforced plastics and studied the influenceof hydraulic pressure on surface roughness.Looking to case of hydraulic pressure, a higherhydraulic pressure increases the kinetic energyof the abrasive particles and enhances theirability for material removal. Whenever thesupply pressure provides sufficiently highenergy to the abrasives, the cutting process isenabled to be carried out without severe jetFigure 4: Effect of Hydraulic Pressure on Surface Roughness390

Int. J. Mech. Eng. & Rob. Res. 2015Abdulhafiz A Shaikh and Jignesh K Patel, 2015Traverse Speeddeflection which in turn minimizes the wavinesspattern. As a result, the Ra decreases asillustrated in Figure 4b. In the AWJM of AFRPlaminate, higher degrees of waviness weregenerally noted on the specimens that weremachined w

The abrasive water jet machining process is characterized by large number of process parameters that determine efficiency, economy and quality of the whole process. Figure 2 demonstrates the factors influencing AWJ machining process. Shanmugam and Masood (2009) have made an investigation on the kerf taper angle, generated by Abrasive Water Jet (AWJ) machining of two kinds of composite .

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