外文翻譯基于注塑模具鋼研磨和拋光工序的自動(dòng)化表面處理

ShiouFJ,ChenCH(2003)Determinationofoptimalball-burnishingparametersforplasticinjectionmoldingsteel.IntJAdvManufTechnolAutomatedsurfacefinishingofplasticinjectionmoldsteelwithsphericalgrindingandballburnishingprocessesChao-ChangA.Chen·Wen-TuLiAbstractThisstudyinvestigatesthepossibilitiesofautomatedsphericalgrindingandballburnishingsurfacefinishingprocessesinafreeformsurfaceplasticinjectionmoldsteelPDS5onaCNCmachiningcenter.Thedesignandmanufactureofagrindingtoolholderhasbeenaccomplishedinthisstudy.TheoptimalsurfacegrindingparametersweredeterminedusingTaguchi’sorthogonalarraymethodforplasticinjectionmoldingsteelPDS5onamachiningcenter.TheoptimalsurfacegrindingparametersfortheplasticinjectionmoldsteelPDS5werethecombinationofanabrasivematerialofPAAl2O3,agrindingspeedof18000rpm,agrindingdepthof20μm,andafeedof50mm/min.ThesurfaceroughnessRaofthespecimencanbeimprovedfromabout1.60μmto0.35μmbyusingtheoptimalparametersforsurfacegrinding.SurfaceroughnessRacanbefurtherimprovedfromabout0.343μmto0.06μmbyusingtheballburnishingprocesswiththeoptimalburnishingparameters.Applyingtheoptimalsurfacegrindingandburnishingparameterssequentiallytoafine-milledfreeformsurfacemoldinsert,thesurfaceroughnessRaoffreeformsurfaceregiononthetestedpartcanbeimprovedfromabout2.15μmto0.07μm.KeywordsAutomatedsurfacefinishing·Ballburnishingprocess·Grindingprocess·Surfaceroughness·Taguchi’smethod1IntroductionPlasticsareimportantengineeringmaterialsduetotheirspecificcharacteristics,suchascorrosionresistance,resistancetochemicals,lowdensity,andeaseofmanufacture,andhaveincreasinglyreplacedmetalliccomponentsinindustrialapplications.Injectionmoldingisoneoftheimportantformingprocessesforplasticproducts.Thesurfacefinishqualityoftheplasticinjectionmoldisanessentialrequirementduetoitsdirecteffectsontheappearanceoftheplasticproduct.Finishingprocessessuchasgrinding,polishingandlappingarecommonlyusedtoimprovethesurfacefinish.Themountedgrindingtools(wheels)havebeenwidelyusedinconventionalmoldanddiefinishingindustries.Thegeometricmodelofmountedgrindingtoolsforautomatedsurfacefinishingprocesseswasintroducedin.Afinishingprocessmodeofsphericalgrindingtoolsforautomatedsurfacefinishingsystemswasdevelopedin.Grindingspeed,depthofcut,feedrate,andwheelpropertiessuchasabrasivematerialandabrasivegrainsize,arethedominantparametersforthesphericalgrindingprocess,asshowninFig.1.TheoptimalsphericalgrindingparametersfortheinjectionmoldsteelhavenotyetbeeninvestigatedbasedintheliteratureInrecentyears,someresearchhasbeencarriedoutindeterminingtheoptimalparametersoftheballburnishingprocess(Fig.2).Forinstance,ithasbeenfoundthatplasticdeformationontheworkpiecesurfacecanbereducedbyusingatungstencarbideballoraroller,thusimprovingthesurfaceroughness,surfacehardness,andfatigueresistance.Theburnishingprocessisaccomplishedbymachiningcentersandlathes.Themainburnishingparametershavingsignificanteffectsonthesurfaceroughnessareballorrollermaterial,burnishingforce,feedrate,burnishingspeed,lubrication,andnumberofburnishingpasses,amongothers.TheoptimalsurfaceburnishingparametersfortheplasticinjectionmoldsteelPDS5wereacombinationofgreaselubricant,thetungstencarbideball,aburnishingspeedof200mm/min,aburnishingforceof300N,andafeedof40μm.Thedepthofpenetrationoftheburnishedsurfaceusingtheoptimalballburnishingparameterswasabout2.5microns.Theimprovementofthesurfaceroughnessthroughburnishingprocessgenerallyrangedbetween40%and90%.Fig.2.Schematicdiagramoftheball-burnishingprocessTheaimofthisstudywastodevelopsphericalgrindingandballburnishingsurfacefinishprocessesofafreeformsurfaceplasticinjectionmoldonamachiningcenter.TheflowchartofautomatedsurfacefinishusingsphericalgrindingandballburnishingprocessesisshowninFig.3.Webeganbydesigningandmanufacturingthesphericalgrindingtoolanditsalignmentdeviceforuseonamachiningcenter.TheoptimalsurfacesphericalgrindingparametersweredeterminedbyutilizingaTaguchi’sorthogonalarraymethod.FourfactorsandthreecorrespondinglevelswerethenchosenfortheTaguchi’sL18matrixexperiment.Theoptimalmountedsphericalgrindingparametersforsurfacegrindingwerethenappliedtothesurfacefinishofafreeformsurfacecarrier.Toimprovethesurfaceroughness,thegroundsurfacewasfurtherburnished,usingtheoptimalballburnishingparameters.Fig.3.Flowchartofautomatedsurfacefinishusingsphericalgrindingandballburnishingprocesses2DesignofthesphericalgrindingtoolanditsalignmentdeviceTocarryoutthepossiblesphericalgrindingprocessofafreeformsurface,thecenteroftheballgrindershouldcoincidewiththez-axisofthemachiningcenter.Themountedsphericalgrindingtoolanditsadjustmentdevicewasdesigned,asshowninFig.4.Theelectricgrinderwasmountedinatoolholderwithtwoadjustablepivotscrews.Thecenterofthegrinderballwaswellalignedwiththehelpoftheconicgrooveofthealignmentcomponents.Havingalignedthegrinderball,twoadjustablepivotscrewsweretightened;afterwhich,thealignmentcomponentscouldberemoved.Thedeviationbetweenthecentercoordinatesoftheballgrinderandthatoftheshankwasabout5μm,whichwasmeasuredbyaCNCcoordinatemeasuringmachine.Theforceinducedbythevibrationofthemachinebedisabsorbedbyahelicalspring.Themanufacturedsphericalgrindingtoolandball-burnishingtoolweremounted,asshowninFig.5.Thespindlewaslockedforboththesphericalgrindingprocessandtheballburnishingprocessbyaspindle-lockingmechanism.Fig.4.SchematicillustrationofthesphericalgrindingtoolanditsadjustmentdeviceFig.5.(a)Photoofthesphericalgrindingtool(b)Photooftheballburnishingtool3Planningofthematrixexperiment3.1ConfigurationofTaguchi’sorthogonalarrayTheeffectsofseveralparameterscanbedeterminedefficientlybyconductingmatrixexperimentsusingTaguchi’sorthogonalarray.Tomatchtheaforementionedsphericalgrindingparameters,theabrasivematerialofthegrinderball(withthediameterof10mm),thefeedrate,thedepthofgrinding,andtherevolutionoftheelectricgrinderwereselectedasthefourexperimentalfactors(parameters)anddesignatedasfactorAtoD(seeTable1)inthisresearch.Threelevels(settings)foreachfactorwereconfiguredtocovertherangeofinterest,andwereidentifiedbythedigits1,2,and3.Threetypesofabrasivematerials,namelysiliconcarbide(SiC),whitealuminumoxide(Al2O3,WA),andpinkaluminumoxide(Al2O3,PA),wereselectedandstudied.Threenumericalvaluesofeachfactorweredeterminedbasedonthepre-studyresults.TheL18orthogonalarraywasselectedtoconductthematrixexperimentforfour3-levelfactorsofthesphericalgrindingprocess.Table1.Theexperimentalfactorsandtheirlevels3.2DefinitionofthedataanalysisEngineeringdesignproblemscanbedividedintosmaller-thebettertypes,nominal-the-besttypes,larger-the-bettertypes,signed-targettypes,amongothers[8].Thesignal-to-noise(S/N)ratioisusedastheobjectivefunctionforoptimizingaproductorprocessdesign.Thesurfaceroughnessvalueofthegroundsurfaceviaanadequatecombinationofgrindingparametersshouldbesmallerthanthatoftheoriginalsurface.Consequently,thesphericalgrindingprocessisanexampleofasmaller-the-bettertypeproblem.TheS/Nratio,η,isdefinedbythefollowingequation:η=?10log10(meansquarequalitycharacteristic)=?10log10where:yi:observationsofthequalitycharacteristicunderdifferentnoiseconditionsn:numberofexperimentAftertheS/NratiofromtheexperimentaldataofeachL18orthogonalarrayiscalculated,themaineffectofeachfactorwasdeterminedbyusingananalysisofvariance(ANOVA)techniqueandanF-ratiotest.Theoptimizationstrategyofthesmaller-thebetterproblemistomaximizeη,asdefinedbyEq.1.Levelsthatmaximizeηwillbeselectedforthefactorsthathaveasignificanteffectonη.Theoptimalconditionsforsphericalgrindingcanthenbedetermined.4ExperimentalworkandresultsThematerialusedinthisstudywasPDS5toolsteel(equivalenttoAISIP20),whichiscommonlyusedforthemoldsoflargeplasticinjectionproductsinthefieldofautomobilecomponentsanddomesticappliances.ThehardnessofthismaterialisaboutHRC33(HS46).Onespecificadvantageofthismaterialisthataftermachining,themoldcanbedirectlyusedforfurtherfinishingprocesseswithoutheattreatmentduetoitsspecialpre-treatment.Thespecimensweredesignedandmanufacturedsothattheycouldbemountedonadynamometertomeasurethereactionforce.ThePDS5specimenwasroughlymachinedandthenmountedonthedynamometertocarryoutthefinemillingonathree-axismachiningcentermadebyYang-IronCompany(typeMV-3A),equippedwithaFUNUCCompanyNC-controller(type0M).Thepre-machinedsurfaceroughnesswasmeasured,usingHommelwerkeT4000equipment,tobeabout1.6μm.Figure6showstheexperimentalset-upofthesphericalgrindingprocess.AMP10touch-triggerprobemadebytheRenishawCompanywasalsointegratedwiththemachiningcentertoolmagazinetomeasureanddeterminethecoordinatedoriginofthespecimentobeground.TheNCcodesneededfortheball-burnishingpathweregeneratedbyPowerMILLCAMsoftware.ThesecodescanbetransmittedtotheCNCcontrollerofthemachiningcenterviaRS232serialinterface.Fig.6.Experimentalset-uptodeterminetheoptimalsphericalgrindingparametersTable2summarizesthemeasuredgroundsurfaceroughnessalueRaandthecalculatedS/NratioofeachL18orthogonalarraysingEq.1,afterhavingexecutedthe18matrixexperiments.TheaverageS/NratioforeachlevelofthefouractorsisshowngraphicallyinFig.7.Table2.GroundsurfaceroughnessofPDS5specimenExp.Innerarray(controlfactors)Measuredsurfaceroughnessvalue(Ra)ResponsenoABCDS/N(η(dB))Mean111110.350.350.359.1190.350212220.370.360.388.6340.370313330.410.440.407.5970.417421230.630.650.643.8760.640522310.730.770.782.3800.760623120.450.420.397.5300.420731320.340.310.329.8010.323832130.270.250.2811.4710.267933210.320.320.329.8970.3201011220.350.390.408.3900.3801112330.410.500.436.9680.4471213110.400.390.427.8830.4031321130.330.340.319.7120.3271422210.480.500.476.3120.4831523320.570.610.534.8680.5701631310.590.550.545.0300.5601732120.360.360.358.9540.3571833230.570.530.535.2930.543Fig.7.PlotsofcontrolfactoreffectsThegoalinthesphericalgrindingprocessistominimizethesurfaceroughnessvalueofthegroundspecimenbydeterminingtheoptimallevelofeachfactor.Since?logisamonotonedecreasingfunction,weshouldmaximizetheS/Nratio.Consequently,wecandeterminetheoptimallevelforeachfactorasbeingthelevelthathasthehighestvalueofη.Therefore,basedonthematrixexperiment,theoptimalabrasivematerialwaspinkaluminumoxide;theoptimalfeedwas50mm/min;theoptimaldepthofgrindingwas20μm;andtheoptimalrevolutionwas18000rpm,asshowninTable3.TheoptimalparametersforsurfacesphericalgrindingobtainedfromtheTaguchi’smatrixexperimentswereappliedtothesurfacefinishofthefreeformsurfacemoldinserttoevaluatethesurfaceroughnessimprovement.Aperfumebottlewasselectedasthetestedcarrier.TheCNCmachiningofthemoldinsertforthetestedobjectwassimulatedwithPowerMILLCAMsoftware.Afterfinemilling,themoldinsertwasfurthergroundwiththeoptimalsphericalgrindingparametersobtainedfromtheTaguchi’smatrixexperiment.Shortlyafterwards,thegroundsurfacewasburnishedwiththeoptimalballburnishingparameterstofurtherimprovethesurfaceroughnessofthetestedobject(seeFig.8).ThesurfaceroughnessofthemoldinsertwasmeasuredwithHommelwerkeT4000equipment.TheaveragesurfaceroughnessvalueRaonafine-milledsurfaceofthemoldinsertwas2.15μmonaverage;thatonthegroundsurfacewas0.45μmonaverage;andthatonburnishedsurfacewas0.07μmonaverage.Thesurfaceroughnessimprovementofthetestedobjectongroundsurfacewasabout(2.15?0.45)/2.15=79.1%,andthatontheburnishedsurfacewasabout(2.15?0.07)/2.15=96.7%.Fig.8.Fine-milled,groundandburnishedmoldinsertofaperfumebottle5ConclusionInthiswork,theoptimalparametersofautomatedsphericalgrindingandball-burnishingsurfacefinishingprocessesinafreeformsurfaceplasticinjectionmoldweredevelopedsuccessfullyonamachiningcenter.Themountedsphericalgrindingtool(anditsalignmentcomponents)wasdesignedandmanufactured.TheoptimalsphericalgrindingparametersforsurfacegrindingweredeterminedbyconductingaTaguchiL18matrixexperiments.TheoptimalsphericalgrindingparametersfortheplasticinjectionmoldsteelPDS5werethecombinationoftheabrasivematerialofpinkaluminumoxide(Al2O3,PA),afeedof50mm/min,adepthofgrinding20μm,andarevolutionof18000rpm.ThesurfaceroughnessRaofthespecimencanbeimprovedfromabout1.6μmto0.35μmbyusingtheoptimalsphericalgrindingconditionsforsurfacegrinding.Byapplyingtheoptimalsurfacegrindingandburnishingparameterstothesurfacefinishofthefreeformsurfacemoldinsert,thesurfaceroughnessimprovementsweremeasuredtobegroundsurfacewasabout79.1%intermsofgroundsurfaces,andabout96.7%intermsofburnishedsurfaces.AcknowledgementTheauthorsaregratefultotheNationalScienceCounciloftheRepublicofChinaforsupportingthisresearchwithgrantNSC89-2212-E-011-059.References1.WangKK(1980)Systemapproachtoinjectionmoldingprocess.Polym-PlastTechnolEng14(1):75–93.2.Shelesh-NezhadK,SioresE(1997)Intelligentsystemforplasticinjectionmoldingprocessdesign.JMaterProcessTechnol63(1–3):458–462.3.AluruR,KeefeM,AdvaniS(2001)Simulationofinjectionmoldingintorapid-prototypedmolds.RapidPrototypingJ7(1):42–51.4.ShenSF(1984)Simulationofpolymericflowsintheinjectionmoldingprocess.IntJNumerMethodsFluids4(2):171–184.5.AgassantJF,AllesH,PhiliponS,VincentM(1988)Experimentalandtheoreticalstudyoftheinjectionmoldingofthermoplasticmaterials.PolymEngSci28(7):460–468.6.ChiangHH,HieberCA,WangKK(1991)Aunifiedsimulationofthefillingandpost-fillingstagesininjectionmolding.PartI:formulation.PolymEngSci31(2):116–124.7.ZhouH,LiD(2001)Anumericalsimulationofthefillingstageininjectionmoldingbasedonasurfacemodel.AdvPolymTechnol20(2):125–131.8.HimasekharK,LotteyJ,WangKK(1992)CAEofmoldcoolingininjectionmoldingusingathree-dimensionalnumericalsimulation.JEngIndTransASME114(2):213–221.9.TangLQ,PochirajuK,ChassapisC,ManoochehriS(1998)Computeraidedoptimizationapproachforthedesignofinjectionmoldcoolingsystems.JMechDes,TransASME120(2):165–174.10.RizzoFJ,ShippyDJ(1977)Anadvancedboundaryintegralequationmethodforthree-dimensionalthermoelasticity.IntJNumerMethodsEng11:1753–1768.11.HartmannF(1980)ComputingtheC-matrixinnon-smoothboundarypoints.In:Newdevelopmentsinboundaryelementmethods,CMLPublications,Southampton,pp367–379.12.ChenX,LamaYC,LiDQ(2000)Analysisofthermalresidualstressinplasticinjectionmolding.JMaterProcessTechnol101(1):275–280.13.LeeEH,RogersTG(1960)Solutionofviscoelasticstressanalysisproblemsusingmeasuredcreeporrelaxationfunction.JApplMech30(1):127–134.14.LiY(1997)Studiesindirecttoolingusingstereolithography.Dissertation,UniversityofDelaware,Newark,DE.基于注塑模具鋼研磨和拋光工序的自動(dòng)化表面處理晁常溫途利摘要本文研究了注塑模具鋼自動(dòng)研磨與球面拋光加工工序的可能性，這種注塑模具鋼P(yáng)DS5的塑性曲面是在數(shù)控加工中心完成的。這項(xiàng)研究已經(jīng)完成了磨削刀架的設(shè)計(jì)與制造。最佳表面研磨參數(shù)是在鋼鐵PDS5的加工中心測定的。對于PDS5注塑模具鋼的最佳球面研磨參數(shù)是以下一系列的組合：研磨材料的磨料為粉紅氧化鋁，進(jìn)給量500毫米/分鐘，磨削深度20微米，磨削轉(zhuǎn)速為18000RPM。用優(yōu)化的參數(shù)進(jìn)行表面研磨，表面粗糙度Ra值可由大約1.60微米改善至0.35微米。用球拋光工藝和參數(shù)優(yōu)化拋光，可以進(jìn)一步改善表面粗糙度Ra值從0.343微米至0.06微米左右。在模具內(nèi)部曲面的測試部分，用最佳參數(shù)的表面研磨、拋光，曲面表面粗糙度就可以提高約2.15微米到00.07微米。關(guān)鍵詞:自動(dòng)化表面處理拋光磨削加工表面粗糙度田口方法一、引言塑膠工程材料由于其重要特點(diǎn),如耐化學(xué)腐蝕性、低密度、易于制造,并已日漸取代金屬部件在工業(yè)中廣泛應(yīng)用。注塑成型對于塑料制品是一個(gè)重要工藝。注塑模具的表面質(zhì)量是設(shè)計(jì)的本質(zhì)要求,因?yàn)樗苯佑绊懥怂苣z產(chǎn)品的外觀和性能。加工工藝如球面研磨、拋光常用于改善表面光潔度。研磨工具(輪子)的安裝已廣泛用于傳統(tǒng)模具的制造產(chǎn)業(yè)。自動(dòng)化表面研磨加工工具的幾何模型將介紹。自動(dòng)化表面處理的球磨研磨工具將得到示范和開發(fā)。磨削速度,磨削深度，進(jìn)給速率和砂輪尺寸、研磨材料特性（如磨料粒度大?。┦乔蛐窝心スに囍兄饕膮?shù)，如圖1（球面研磨過程示意圖）所示。注塑模具鋼的球面研磨最優(yōu)化參數(shù)目前尚未在文獻(xiàn)得到確切的依據(jù)。步距步距研磨高度球磨研磨進(jìn)給速度工作臺圖1球面研磨過程示意圖進(jìn)給研磨球工作臺研磨深度研磨表面近年來，已經(jīng)進(jìn)行了一些研究，確定了球面拋光工藝的最優(yōu)參數(shù)(圖2)（球面拋光過程示意圖）。比如，人們發(fā)現(xiàn),用碳化鎢球滾壓的方法可以使工件表面的塑性變形減少,從而改善表面粗糙度、表面硬度、抗疲勞強(qiáng)度。拋光的工藝的過程是由加工中心和車床共同完成的。對表面粗糙度有重大影響的拋光工藝主要參數(shù)，主要是球或滾子材料，拋光力，進(jìn)給速率,拋光速度,潤滑、拋光率及其他因素等。注塑模具鋼P(yáng)DS5的表面拋光的參數(shù)優(yōu)化，分別結(jié)合了油脂潤滑劑，碳化鎢球,拋光速度200毫米/分鐘,拋光力300牛，40微米的進(jìn)給量。采用最佳參數(shù)進(jìn)行表面研磨和球面拋光的深度為2.5微米。通過拋光工藝，表面粗糙度可以進(jìn)給研磨球工作臺研磨深度研磨表面圖2球面拋光過程示意圖此項(xiàng)目研究的目的是，發(fā)展注塑模具鋼的球形研磨和球面拋光工序，這種注塑模具鋼的曲面實(shí)在加工中心完成的。表面光潔度的球研磨與球拋光的自動(dòng)化流程工序，如圖3所示。我們開始自行設(shè)計(jì)和制造的球面研磨工具及加工中心的對刀裝置。利用田口正交法，確定了表面球研磨最佳參數(shù)。選擇為田口L18型矩陣實(shí)驗(yàn)相應(yīng)的四個(gè)因素和三個(gè)層次。用最佳參數(shù)進(jìn)行表面球研磨則適用于一個(gè)曲面表面光潔度要求較高的注塑模具。為了改善表面粗糙,利用最佳球面拋光工藝參數(shù)，再進(jìn)行對表層打磨。PDS試樣的設(shè)計(jì)與制造PDS試樣的設(shè)計(jì)與制造選擇最佳矩陣實(shí)驗(yàn)因子確定最佳參數(shù)實(shí)施實(shí)驗(yàn)分析并確定最佳因子進(jìn)行表面拋光應(yīng)用最佳參數(shù)加工曲面測量試樣的表面粗糙度球研磨和拋光裝置的設(shè)計(jì)與制造圖3自動(dòng)球面研磨與拋光工序的流程圖二、球研磨的設(shè)計(jì)和對準(zhǔn)裝置實(shí)施過程中可能出現(xiàn)的曲面的球研磨,研磨球的中心應(yīng)和加工中心的Z軸相一致。球面研磨工具的安裝及調(diào)整裝置的設(shè)計(jì)，如圖4（球面研磨工具及其調(diào)整裝置）所示。電動(dòng)磨床展開了兩個(gè)具有可調(diào)支撐螺絲的刀架。磨床中心正好與具有輔助作用的圓錐槽線配合。擁有磨床的球接軌,當(dāng)兩個(gè)可調(diào)支撐螺絲被收緊時(shí)，其后的對準(zhǔn)部件就可以拆除。研磨球中心坐標(biāo)偏差約為5微米,這是衡量一個(gè)數(shù)控坐標(biāo)測量機(jī)性能的重要標(biāo)準(zhǔn)。機(jī)床的機(jī)械振動(dòng)力是被螺旋彈簧所吸收。球形研磨球和拋光工具的安裝，如圖5（a.球面研磨工具的圖片.b.球拋光工具的圖片）所示。為使球面磨削加工和拋光加工的進(jìn)行，主軸通過球鎖機(jī)制而被鎖定。模柄模柄彈簧工具可調(diào)支撐緊固螺釘磨球自動(dòng)研磨磨球組件圖4球面研磨工具及其調(diào)整裝置圖5a.球面研磨工具的圖片.b.球拋光工具的圖片三、矩陣實(shí)驗(yàn)的規(guī)劃3.1田口正交表利用矩陣實(shí)驗(yàn)田口正交法，可以確定參數(shù)的有影響程度。為了配合上述球面研磨參數(shù)，該材料磨料的研磨球(直徑10毫米),進(jìn)給速率，研磨深度,在次研究中電氣磨床被假定為四個(gè)因素，指定為從A到D（見表1實(shí)驗(yàn)因素和水平）。三個(gè)層次的因素涵蓋了不同的范圍特征,并用了數(shù)字1、2、3標(biāo)明。挑選三類磨料,即碳化硅,白色氧化鋁,粉紅氧化鋁來研究.這三個(gè)數(shù)值的大小取決于每個(gè)因素實(shí)驗(yàn)結(jié)果。選定L18型正交矩陣進(jìn)行實(shí)驗(yàn)，進(jìn)而研究四——三級因素的球形研磨過程。表1實(shí)驗(yàn)因素和水平因素水平123A.碳化硅白色氧化鋁粉紅氧化鋁B.50100200C.研磨深度（μm）205080D.1200018000240003.2數(shù)據(jù)分析的界定工程設(shè)計(jì)問題,可以分為較小而好的類型,象征性最好類型,大而好類型，目標(biāo)取向類型等。信噪比(S/N)的比值，常作為目標(biāo)函數(shù)來優(yōu)化產(chǎn)品或者工藝設(shè)計(jì)。被加工面的表面粗糙度值經(jīng)過適當(dāng)?shù)亟M合磨削參數(shù)，應(yīng)小于原來的未加工表面。因此,球面研磨過程屬于工程問題中的小而好類型。這里的信噪比（S/N）,η,按下列公式定義:η=?10log平方等于質(zhì)量特性=?10log（1）這里，y——不同噪聲條件下所觀察的質(zhì)量特性n——實(shí)驗(yàn)次數(shù)從每個(gè)L18型正交實(shí)驗(yàn)得到的信噪比（S/N）數(shù)據(jù)，經(jīng)計(jì)算后，運(yùn)用差異分析技術(shù)(變異)和殲比檢驗(yàn)來測定每一個(gè)主要的因素。優(yōu)化小而好類型的工程問題問題更是盡量使η最大而定。各級η選擇的最大化將對最終的η因素有重大影響。最優(yōu)條件可視研磨球而待定。四、實(shí)驗(yàn)工作和結(jié)果這項(xiàng)研究使用的材料是PDS5工具鋼(相當(dāng)于艾西塑膠模具)，它常用于大型注塑模具產(chǎn)品在國內(nèi)汽車零件領(lǐng)域和國內(nèi)設(shè)備。該材料的硬度約HRC33(HS46)。具體好處之一是,由于其特殊的熱處理前處理，模具可直接用于未經(jīng)進(jìn)一步加工工序而對這一材料進(jìn)行加工。式樣的設(shè)計(jì)和制造,應(yīng)使它們可以安裝在底盤，來測量相應(yīng)的反力。PDS5試樣的加工完畢后，裝在大底盤上在三坐標(biāo)加工中心進(jìn)行了銑削，這種加工中心是由鋼鐵公司所生產(chǎn)(中壓型三號),配備了FANUC-18M公司的數(shù)控控制器(0.99型)。用hommelwerket4000設(shè)備來測量前機(jī)加工前表面的粗糙度,使其可達(dá)到1.6微米。圖6試驗(yàn)顯示了球面磨削加工工藝的設(shè)置。一個(gè)由Renishaw公司生產(chǎn)的視頻觸摸觸發(fā)探頭，安裝在加工中心上，來測量和確定和原始式樣的協(xié)調(diào)。數(shù)控代碼所需要的磨球路徑由PowerMILL軟件產(chǎn)。這些代碼經(jīng)過RS232串口界面，可以傳送到裝有控制器的數(shù)控加工中心上。加工中心加工中心數(shù)控機(jī)床電腦圖6完成了L18型矩陣實(shí)驗(yàn)后，表2（PDS5試樣光滑表層的粗糙度）總結(jié)了光滑表面的粗糙度RA值，計(jì)算了每一個(gè)L18型矩陣實(shí)驗(yàn)的信噪比（S/N）,從而用于方程（1）。通過表2提供的各個(gè)數(shù)值，可以得到四種不同程度因素的平均信噪比（S/N），在圖7中已用圖表顯示。表2PDS5試樣光滑表層的粗糙度實(shí)驗(yàn)序號ABCDS/N(η(dB))Mean111110.350.350.359.1190.350212220.370.360.388.6340.370313330.410.440.407.5970.417421230.630.650.643.8760.640522310.730.770.782.3800.760623120.450.420.397.5300.420731320.340.310.329.8010.323832130.270.250.2811.4710.267933210.320.320.329.8970.3201011220.350.390.408.3900.3801112330.410.500.436.9680.4471213110.400.390.427.8830.4031321130.330.340.319.7120.3271422210.480.500.476.3120.4831523320.570.610.534.8680.5701631310.590.550.545.0300.5601732120.360.360.358.9540.3571833230.570.530.535.2930.543控制因素信噪比圖7控制影響因素控制因素信噪比球面研磨工藝的目標(biāo)，就是通過確定每一種因子的最佳優(yōu)化程度值，來使試樣光滑表層的表面粗糙度值達(dá)到最小。因?yàn)?log是一個(gè)減函數(shù)，我們應(yīng)當(dāng)使信噪比（S/N）達(dá)到最大。因此，我們能夠確定每一種因子的最優(yōu)程度使得η的值達(dá)到最大。因此基于這個(gè)點(diǎn)陣式實(shí)驗(yàn)的最優(yōu)轉(zhuǎn)速應(yīng)該是18000RPM，如表3（優(yōu)化組合球面研磨參數(shù)）所示。表3優(yōu)化組合球面研磨參數(shù)因素水平白色氧化鋁50mm/min20μm18000rpm從田口矩陣實(shí)驗(yàn)獲得的球面研磨優(yōu)化參數(shù)，適用于曲面光滑的模具，從而改善表面的粗糙度。選擇香水瓶為一個(gè)測試載體。對于被測物體的模具數(shù)控加工中心，由PowerMILL軟件來模擬測試。經(jīng)過精銑，通過使用從田口矩陣實(shí)驗(yàn)獲得的球面研磨優(yōu)化參數(shù)，模具表面進(jìn)一步光滑。緊接著,使用打磨拋光的最佳參數(shù)，來對光滑曲面進(jìn)行拋光工藝，進(jìn)一步改善了被測物體的表面粗糙度。(見圖9)。模具內(nèi)部的表面粗糙度用hommelwerket4000設(shè)備來測量。模具內(nèi)部的表面粗糙度RA的平均值為2.15微米，光滑表面粗糙度RA的平均值為0.45微米，拋光表面粗糙度RA的平均值為0.07微米。被測物體的光滑表面的粗糙度改善了：(2.15-0.45)/2.15=79.1％，拋光表面的粗糙度改善了：(2.15-0.07)/2.15=96.7％。拋光表面拋光表面Ra=0.07μm內(nèi)部表面Ra=2.15μm光滑表面Ra=0.45μm圖8被測物體表面粗糙五、結(jié)論在這項(xiàng)工作中,對注塑模具的曲面進(jìn)行了自動(dòng)球面研磨與球面拋光加工，并將其工藝最佳參數(shù)成功地運(yùn)用到加工中心