制造業(yè)用于提高表面光潔度和減少切削力的拋丸清理機-畢設(shè)翻譯

./畢業(yè)設(shè)計〔論文〕英文資料翻譯MicroShotBlastingofMachineTools學(xué)院：西北工業(yè)大學(xué)明德學(xué)院專業(yè)：機械設(shè)計制造與自動化班級：161003班__王偉學(xué)號：指導(dǎo)2015年6月MicroshotblastingofmachinetoolsforimprovingsurfacefinishandreducingcuttingforcesinmanufacturingD.M.Kennedy*,J.Vahey,D.HanneyFacultyofEngineering,DublinInstituteofTechnology,BoltonStreet,Dublin1,IrelandReceived5January2004;accepted3February2004Availableonline13April2004AbstractMicroblastingofcuttingtipsandtoolsisaveryeffectiveandreliablemethodofadvancingthelifeoftoolsundertheactionofturning,milling,drilling,punchingandcutting.Thispaperoutlinesthewaysinwhichmicroblastedtools,bothcoatedanduncoatedhavebenefitedfromshotblastingandresultedingreaterproductivity,lowercuttingforces,improvedsurfacefinishoftheworkpiecesandlessmachinedowntime.Theprocessofmicroblastingisdiscussedinthepaper.Itseffectivenessdependsonmanyparametersincludingtheshotmediaandsize,themechanicsofimpactandtheapplicationoftheshotviathemicroshotblastingunit.Controloftheprocesstoproviderepeatabilityandreliabilityintheshotblastingunitisdiscussed.Comparisonsbetweentreatedanduntreatedcuttingtoolsaremadeandresultsoftoollifeforthesecuttingtipsoutlined.Theprocesshasshowntobeofmajorbenefittotoollifeimprovement.2004ElsevierLtd.Allrightsreserved.Keywords:Microshotblasting;Surfacefinish;Machinetools1.IntroductionManymoderntechniqueshavebeendevelopedtoenhancethelifeofcomponentsinservice,suchasalloyingadditions,heattreatment,surfaceengineering,surfacecoating,implantationprocesses,lasertreatmentandsurfaceshapedesign.Processessuchasthinfilmtechnology,plasmaspraying,vacuumtechniquesdepositingarangeofmulti-layeredcoatingshavegreatlyenhancedthelife,useandapplicationsofengineeringcomponentsandmachinetools.Bombardmentwithmillionsofmicroshotranginginsizefrom4to50lmwithacontrolledprocesscanleadtodramaticoperatinglifeimprovementsofcomponents.StandardshotpeeningwasfirstusedinaproductionprocesstoextendthelifeofvalvespringsforBuickandCadillacenginesintheearly1930s[1,2]butpriortothisitwasawellknownprocessusedbyblacksmithsandswordmakersovertimetoimprovethetoughnessofthecuttingedgesoftheirtoolsandweapons.Today,cuttingtipsandtoolscanbegreatlyimprovedbytheprocessofmicroshotblastingtheirsurfacestoinducecompressiveresidualstresses.Theoperatinglifeoftoolssuchasdrills,turningtips,millingtips,punches,knifeedges,slicers,blades,andarangeofotherworkingpartscanalsobenefitfromthisprocess.Standardcomponents,suchassprings,dies,shafts,cams,anddynamiccomponentsinmachinesandenginescanbeenhancedbythisprocess.Thefatiguelifeofcompressorcomponentsforexample,treatedbyshotpeeninghaveincreaseddramaticallyasreportedbyEckersleyandFerrelli[3].Otherfactorssuchasimprovedfatigueresistance,microcrackclosure,reducedcorrosionandanimprovedsurfacefinishcanalsobedesignedintocomponentsasaresultofthisthepeeningprocess.Notonlycanimprovementsbemadetothesurfacefinishofthecuttingtipsandtoolsbutalsothesurfacefinishoftheworkpiecesmachinedwiththesetoolshaveimprovedasaresultofthistechnique.Engineeringmaterialssuchastoolssteels,carbides,ceramics,coatedcarbides,throughtopolymersandevenrubbers<elastomers>canbenefit.Thekeyrequirementforthisprocessistodevelopanautomatedmicroblastingprocesstofitinsideasprayboothorstandardshotblastingbooth.Shotmaterial,sizeandmass,operatingpressures,operatingvelocities,kineticenergy,densityandcoveragetimewillneedtobeperfectedandoptimisedforarangeofmaterials.Theprocessisalineofsightmethodbutcanbeappliedtocomplexsurfaceshapessuchasthetipsofdrillbits.2.MethodofoperationOneoftheprimarywaysthatcomponentsfailinerviceisthroughfatigue.Thisiscloselyassociatedwithcyclicstressesandacceleratedbytensilestresses,microcrackpropagationandstresscorrosioncracking.Cracksreducethecrosssectionofamaterialandeventuallyitwillfailtosupporttheappliedloads.Onesimplemethodofreducingfailurebyfatigueistoarrestthesetensilestressesbyinducingcompressivestressesintoasurface.Thebenefitsobtainedwithshotpeeningareadirectresultoftheresidualcompressivestressesproducedinacomponent.AtypicalshotstrikingasurfaceisshowninFig.1.AnyappliedtensileloadswouldhavetoovercometheresidualcompressivestressesbeforeacrackcouldinitiateasdescribedbyAlmen[4].Poormachiningofmaterialscanresultinresidualstressesaccruingatthesurface.Roughsurfaceshavedeepernotches,wherecrackscaninitiateduetotensilestressconcentrationsatthesepoints.Manystandardmachiningprocessessuchasgrinding,milling,turning,andcoatingprocessessuchaselectroplatinginduceresidualtensilestressesinsurfacesandthiscanleadtoearlyfailureofcomponents.Furthertensileloadinginservicewouldleadtoearlyfailureandthiscanbepreventedbyshotpeeningandmicroblastingofcomponentsurfaces.Microshotblastingwillchangethefollowinginamaterialssurface:<i>resistancetofatiguefracture;<ii>resistancetostresscorrosion;<iii>achangeinresidualstresses;<iv>modificationofsurfacefinish.Itisacoldworkingprocessinvolvingbombardingpowderssuchasceramics,glassandmetalsofmainlysphericalshapesagainstsurfacesandcanbeusedinconjunctionwithotherprocesses.Themainstagesinvolvedinthisdynamicprocessincludeelasticrecoveryofthesubstrateafterimpact,someplasticdeformationofthesubstrateiftheimpactpressureexceedstheyieldstress,increasedplasticdeformationduetoanincreaseinimpactpressureandfinallysomereboundoftheshotduetoareleaseofelasticenergy.Somecriticaldesigncharacteristicsofthemicroshotpeeningprocessincludetheshotsize,shape,hardness,density,durability,angleofimpact,velocityandintensity.Alloftheseparameterswillinfluencetheresidualcompressivestressesproducedinthesubstrate.3.ExperimentalworkToolmaterialssuchasTungstenCarbide,HighSpeedSteelsusedinmillingandturningtoolsweresubjectedtothemicropeeningprocessusingdifferentshotmedia<ceramicandglassbead>andshotsize.Testspriortoandfollowingtheblastingprocesswereconductedtoascertainanyimprovementsresultingfromtheprocess.ThemicroshotpeeningunitisshowninPhoto1itincorporatesanairfilter,pressureregulatorandgauge,airflowregulator,pressurisedblastmediacontainerandaventuriblastnozzlefordirectingthestreamofmicroshot.TheunitisPLCcontrolledandasteppermotor,usedtodrivealeadscrew,isusedtomovetheblastnozzleacrossthesampleinordertocontrolmediashotcoverage.Theblastnozzlecanalsoberotatedtoallowshotmediatostrikethesamplesatdifferentangles.Testsundertakenincludesurfacefinishandroughnessmeasurement,machiningtestsonstandardlathesandmills,hardnesstests,cuttingforcesonturningoperations,toolwearandthedeterminationofsurfacefinishoftheworkpiecesmachined.Figs.2and3showatypicalhighspeedsteel<HSS>tippriortoandfollowingthemicroshotpeeningprocessusingceramicbeadatapressureof5.5bar.4.ExperimentalresultsTestingoftreatedanduntreatedcuttingtipsandtoolswasconductedonHSSsforturningandmillingaswellascoatedanduncoatedcarbideinserts.Adynamometerwasusedtomeasurecuttingforcesontheturningtool<Lathe>.Thecuttingprocessconsistedofadepthofcutof2mmonastandardbrightmildsteelspecimenoveralengthof750mmwhilemillingtestsconsistedofmachininga25_25_150mmpieceofmildsteelusingadepthofcutof1mmwithaslotmillingcutterof18mmdiameter.Surfaceroughnessmeasurementswereconductedonthemachinedcomponentspriortoandaftermachiningtoestablishwhetherthetreatedcuttingtipshadsuperiorperformancetotheuntreatedtips.MicroHardnesstestingwasalsocarriedouttoestablishiftherewasanyincreaseinsurfacehardnessduetothemicroshotpeeningprocess.Theimpactangleoftheshotwassetat90_asthisprovidestheoptimumcompressivelayer[5].Theshotvelocityonimpactwithasurfaceislargelydependentonthenozzlesize,theairpressureandthedistancefromthesubstrate.TheexposuretimewasadequatetogivesufficientcoverageofthesubstrateandthiswasdeterminedbytheAlmenstripsaturationtime,workpieceindentationtimeandvisualappearance.Hardermaterialssuchascarbideswillobviouslyrequirelongerexposuretimeorhardershotmedia.Themicropeeningmediausedwasaceramicbeadofapproximately40lmdiameterprovidinghighimpactstrengthandhardness<NFL06-824,approximately60HRc>.4.1.MicrohardnesstestsCombinedVickersmicrohardnesstestsgavetheresultsinTable1.forbothtreatedanduntreatedHSScuttingtips.4.2.SurfaceroughnessvaluesInallsurfaceroughnesstestsconducted,themicroblastedsurfacegaveanimprovedsurfaceroughnessvalue.SurfaceroughnessandprofiletestswerecarriedoutonbothaTalyorHobsonTallysurfinstrumentandanoncontactsurfaceprofileometer.SurfaceroughnessdetailsofatypicaluntreatedHSScuttingtipandatreatedoneareshowninFigs.4and5andTable2showstheresultsofsurfacemeasurementvaluesforothercuttingtipsandtoolsandworkpieces.Fig.6showsanuncoatedcarbidecuttingtipwhichwasnotsubjectedtomicroblasting.Theflankwearwasmeasuredusinganopticalmicroscopeandthevaluerecordedwas150lmafter676sofmachining.Fig.7showsanuncoatedcarbidetipsubjectedtomicroblasting.Theflankwearinthiscaseisonly90lmforthesamemachiningtime.and5andTable2showstheresultsofsurfacemeasurementvaluesforothercuttingtipsandtoolsandworkpieces.Fig.6showsanuncoatedcarbidecuttingtipwhichwasnotsubjectedtomicroblasting.Theflankwearwasmeasuredusinganopticalmicroscopeandthevaluerecordedwas150lmafter676sofmachining.Fig.7showsanuncoatedcarbidetipsubjectedtomicroblasting.Theflankwearinthiscaseisonly90lmforthesamemachiningtime.4.3.DynamometertestsFigs.8and9showthecomparisonforDynamometerresultsforHSSinthetreated<microblasted>anduntreatedstateswithrelevantcomments.Similarprofilesareshownforcoatedanduncoatedturningtipsinboththetreated<microblasted>anduntreatedconditionsinFigs.10–13.Inallcases,themicroblastedtipsprovidedanincreaseincuttingtiplifewithlowercuttingforcesrecorded.5.ConclusionsThisresearchworkhasshownthatmicroshotblastingofcuttingtipsandtoolshasaverypositiveeffectoncomponentsurfacesbyincreasingtoughness,operatinglife,improvinghardnessandsurfacefinish.Fromthetestsconducted,itisobviousthattheprocessaffectstheresidualstressesatornearthesurfaceinabeneficialwaybyinducingcompressivestressesonthesubstratestested.Themicroblastingprocessisverysimpletoapplyandeconomicaltouse.Themechanicalpropertiesofthesubstrateswilldeterminethetypeoftreatment,i.e.shothardness,velocityanddurationofapplicationinordertoobtainmaximumbenefitsfromthisprocess.Insomecases,authorshavereporteda4–10foldimprovementinfatiguelifeinarangeofdynamicmachinepartssubjectedtostandardshotblasting.Furthertestingwillneedtobeconductedatthemicroshotblastingstagetoobtainsimilarbenefits.Otherapplicationsforthemicroblastingprocessarecurrentlybeinginvestigatedandrubberbasedproductsthataresubjectedtofatigueandweararebeingtestedinordertoremovethesurfacevoidsthatactasstressconcentrationsinthesematerials.References[1]Impact.Bloomfield,CT:MetalImprovementCompany;Fall1989.[2]ZimmerliFP.Heattreating,settingandshot-peeningofmechanicalsprings.Metalprocess;June1952.[3]EckersleyJS,FerrelliB.Usingshot-peeningtomultiplythelifeofcompressorcomponents.In:Theshotpeener,Internationalnewsletterforshot-peeningsurfacefinishingindustry,vol.9,IssueNo.1;March1995.[4]AlmenJC.J.O.Almenonhotblasting.Generalmotorstest,USPatent2,350,440.[5]ChampaigneJ.Controlledshotpeening.ElecInc.,Report;1989.制造業(yè)用于提高表面光潔度和減少切削力的拋丸清理機摘要在旋轉(zhuǎn),銑削,鉆孔,沖孔和切削運動中,微拋丸切削技巧和工具是一種提高工具壽命的非常高效并且可靠的方法。本文概述了應(yīng)用微拋丸工具的方式,微拋丸對有無鍍膜工件的益處,并且創(chuàng)造了更大的生產(chǎn)力,降低了切應(yīng)力,提高了工件的表面光潔度,減少了機器的停機時間。本文對微拋丸過程進(jìn)行了討論。它的效率取決于包括彈丸媒體和型號在內(nèi)的許多參數(shù),碰撞力學(xué)和通過微拋丸單元的彈丸的應(yīng)用程序。對控制流程提供的可重復(fù)性和可靠性的爆破裝置進(jìn)行了探討。處理和未經(jīng)處理的刀具的做出了對比,切割技巧對刀具壽命的影響做出了概述。這個過程體現(xiàn)了提高工具壽命的主要好處。2004愛思唯爾XX保留所有權(quán)利。關(guān)鍵詞:微噴丸清理,表面光潔度;機床介紹許多現(xiàn)代技術(shù)已經(jīng)開發(fā)出來加強服務(wù)組件的壽命,例如添加合金,熱處理,表面工程,表面涂層,移植過程,激光治療以與表面外形設(shè)計。例如薄膜技術(shù),等離子噴涂,沉淀多層涂料的真空技術(shù)都大大加強了壽命,工程和應(yīng)用程序組件和機床使用。通過控制過程用數(shù)以百萬計的大小在4到50微米的微拋丸撞擊可以顯著提高組件的使用壽命。標(biāo)準(zhǔn)噴丸技術(shù)首次使用時在20世紀(jì)30年代提高別克和凱迪拉克引擎氣門彈簧的生產(chǎn)過程中,但在此之前該技術(shù)就是被鐵匠和刀制造商所熟知的來提高他們工具和武器切削刃韌性的過程。當(dāng)今,切割技巧和工具可以通過微拋丸清理它們的表面的過程來引導(dǎo)壓縮參與應(yīng)力而被大大提高。鉆頭,車削頭,銑削頭,沖頭,刀刃,切片機,葉片以與一系列的其他工作部分都可以受益于該過程。機器和引擎中的標(biāo)準(zhǔn)組件,例如離合器,柴油機,軸,凸輪以與動態(tài)組件等都可以通過該過程提高。由Eckersley和Ferrelli所述,例如壓縮機組件的疲勞壽命通過拋丸處理可以顯著增加。其他因素,例如抗疲勞強度,微裂紋閉合,減少腐蝕以與提高表面光潔度都可以被作為噴丸的結(jié)果而被設(shè)計進(jìn)組件當(dāng)中。不僅可以做到切削刀具表面光潔度的提高,而且由這些刀具加工的工件的表面光潔度作為該技術(shù)的一個成果也得到了提高。工程材料中,例如工具鋼,硬質(zhì)合金,陶瓷,涂層硬質(zhì)合金,通過聚合物甚至橡膠〔彈性物〕都可以受益。這個過程的關(guān)鍵要求是開發(fā)一個自動化微拋丸的工藝過程來適用于噴漆柜或者標(biāo)準(zhǔn)拋丸位置。拋丸材料,大小和質(zhì)量,操作壓力,操作速度,動能,密度,覆蓋時間都要被完美優(yōu)化一系列材料。這個過程是一種視線方法卻可以應(yīng)用于復(fù)雜外形例如鉆孔。操作方法服務(wù)組件損壞的主要原因之一是疲勞使用。這是與循環(huán)應(yīng)力密切相關(guān),加速了抗拉應(yīng)力,微裂紋擴(kuò)展和應(yīng)力腐蝕開裂。裂紋減少材料的橫截面,最終它將無法支持應(yīng)用加載。減少疲勞的失敗的一個簡單方法是通過誘導(dǎo)壓應(yīng)力到表面來停止這些拉伸應(yīng)力。拋丸加工直接產(chǎn)生的好處是一個組件產(chǎn)生的殘余壓應(yīng)力。典型的鏡頭的表面是圖1所示。在由阿爾門[4]描述的裂紋出現(xiàn)之前,任何應(yīng)用拉伸加載將不得不克服殘余壓應(yīng)力。不良的加工材料會導(dǎo)致殘留表面壓力積累。粗糙表面有更深層次的等級,在這些點,由于拉應(yīng)力會產(chǎn)生裂紋。許多標(biāo)準(zhǔn)磨削,銑削、車削和涂層工藝?yán)珉婂兊燃庸み^程,在表面產(chǎn)生殘余拉應(yīng)力,這可能會導(dǎo)致早期失效的組件。進(jìn)一步拉伸加載服務(wù)會導(dǎo)致早期失效,這可以防止噴丸加工和微拋丸組件表面。微拋丸處理將改變以下材料表面：抗疲勞斷裂；抗應(yīng)力腐蝕；