外文翻译基于注塑模具钢研磨和抛光工序的自动化表面处理

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.基于注塑模具钢研磨和抛光工序的自动化表面处理晁常温途利摘要本文研究了注塑模具钢自动研磨与球面抛光加工工序的可能性，这种注塑模具钢PDS5的塑性曲面是在数控加工中心完成的。这项研究已经完成了磨削刀架的设计与制造。最佳表面研磨参数是在钢铁PDS5的加工中心测定的。对于PDS5注塑模具钢的最佳球面研磨参数是以下一系列的组合：研磨材料的磨料为粉红氧化铝，进给量500毫米/分钟，磨削深度20微米，磨削转速为18000RPM。用优化的参数进行表面研磨，表面粗糙度Ra值可由大约1.60微米改善至0.35微米。用球抛光工艺和参数优化抛光，可以进一步改善表面粗糙度Ra值从0.343微米至0.06微米左右。在模具内部曲面的测试部分，用最佳参数的表面研磨、抛光，曲面表面粗糙度就可以提高约2.15微米到00.07微米。关键词:自动化表面处理抛光磨削加工表面粗糙度田口方法一、引言塑胶工程材料由于其重要特点,如耐化学腐蚀性、低密度、易于制造,并已日渐取代金属部件在工业中广泛应用。注塑成型对于塑料制品是一个重要工艺。注塑模具的表面质量是设计的本质要求,因为它直接影响了塑胶产品的外观和性能。加工工艺如球面研磨、抛光常用于改善表面光洁度。研磨工具(轮子)的安装已广泛用于传统模具的制造产业。自动化表面研磨加工工具的几何模型将介绍。自动化表面处理的球磨研磨工具将得到示范和开发。磨削速度,磨削深度，进给速率和砂轮尺寸、研磨材料特性（如磨料粒度大小）是球形研磨工艺中主要的参数，如图1（球面研磨过程示意图）所示。注塑模具钢的球面研磨最优化参数目前尚未在文献得到确切的依据。步距步距研磨高度球磨研磨进给速度工作台图1球面研磨过程示意图进给研磨球工作台研磨深度研磨表面近年来，已经进行了一些研究，确定了球面抛光工艺的最优参数(图2)（球面抛光过程示意图）。比如，人们发现,用碳化钨球滚压的方法可以使工件表面的塑性变形减少,从而改善表面粗糙度、表面硬度、抗疲劳强度。抛光的工艺的过程是由加工中心和车床共同完成的。对表面粗糙度有重大影响的抛光工艺主要参数，主要是球或滚子材料，抛光力，进给速率,抛光速度,润滑、抛光率及其他因素等。注塑模具钢PDS5的表面抛光的参数优化，分别结合了油脂润滑剂，碳化钨球,抛光速度200毫米/分钟,抛光力300牛，40微米的进给量。采用最佳参数进行表面研磨和球面抛光的深度为2.5微米。通过抛光工艺，表面粗糙度可以进给研磨球工作台研磨深度研磨表面图2球面抛光过程示意图此项目研究的目的是，发展注塑模具钢的球形研磨和球面抛光工序，这种注塑模具钢的曲面实在加工中心完成的。表面光洁度的球研磨与球抛光的自动化流程工序，如图3所示。我们开始自行设计和制造的球面研磨工具及加工中心的对刀装置。利用田口正交法，确定了表面球研磨最佳参数。选择为田口L18型矩阵实验相应的四个因素和三个层次。用最佳参数进行表面球研磨则适用于一个曲面表面光洁度要求较高的注塑模具。为了改善表面粗糙,利用最佳球面抛光工艺参数，再进行对表层打磨。PDS试样的设计与制造PDS试样的设计与制造选择最佳矩阵实验因子确定最佳参数实施实验分析并确定最佳因子进行表面抛光应用最佳参数加工曲面测量试样的表面粗糙度球研磨和抛光装置的设计与制造图3自动球面研磨与抛光工序的流程图二、球研磨的设计和对准装置实施过程中可能出现的曲面的球研磨,研磨球的中心应和加工中心的Z轴相一致。球面研磨工具的安装及调整装置的设计，如图4（球面研磨工具及其调整装置）所示。电动磨床展开了两个具有可调支撑螺丝的刀架。磨床中心正好与具有辅助作用的圆锥槽线配合。拥有磨床的球接轨,当两个可调支撑螺丝被收紧时，其后的对准部件就可以拆除。研磨球中心坐标偏差约为5微米,这是衡量一个数控坐标测量机性能的重要标准。机床的机械振动力是被螺旋弹簧所吸收。球形研磨球和抛光工具的安装，如图5（a.球面研磨工具的图片.b.球抛光工具的图片）所示。为使球面磨削加工和抛光加工的进行，主轴通过球锁机制而被锁定。模柄模柄弹簧工具可调支撑紧固螺钉磨球自动研磨磨球组件图4球面研磨工具及其调整装置图5a.球面研磨工具的图片.b.球抛光工具的图片三、矩阵实验的规划3.1田口正交表利用矩阵实验田口正交法，可以确定参数的有影响程度。为了配合上述球面研磨参数，该材料磨料的研磨球(直径10毫米),进给速率，研磨深度,在次研究中电气磨床被假定为四个因素，指定为从A到D（见表1实验因素和水平）。三个层次的因素涵盖了不同的范围特征,并用了数字1、2、3标明。挑选三类磨料,即碳化硅,白色氧化铝,粉红氧化铝来研究.这三个数值的大小取决于每个因素实验结果。选定L18型正交矩阵进行实验，进而研究四——三级因素的球形研磨过程。表1实验因素和水平因素水平123A.碳化硅白色氧化铝粉红氧化铝B.50100200C.研磨深度（µm）205080D.1200018000240003.2数据分析的界定工程设计问题,可以分为较小而好的类型,象征性最好类型,大而好类型，目标取向类型等。信噪比(S/N)的比值，常作为目标函数来优化产品或者工艺设计。被加工面的表面粗糙度值经过适当地组合磨削参数，应小于原来的未加工表面。因此,球面研磨过程属于工程问题中的小而好类型。这里的信噪比（S/N）,η,按下列公式定义:η=−10log平方等于质量特性=−10log（1）这里，y——不同噪声条件下所观察的质量特性n——实验次数从每个L18型正交实验得到的信噪比（S/N）数据，经计算后，运用差异分析技术(变异)和歼比检验来测定每一个主要的因素。优化小而好类型的工程问题问题更是尽量使η最大而定。各级η选择的最大化将对最终的η因素有重大影响。最优条件可视研磨球而待定。四、实验工作和结果这项研究使用的材料是PDS5工具钢(相当于艾西塑胶模具)，它常用于大型注塑模具产品在国内汽车零件领域和国内设备。该材料的硬度约HRC33(HS46)。具体好处之一是,由于其特殊的热处理前处理，模具可直接用于未经进一步加工工序而对这一材料进行加工。式样的设计和制造,应使它们可以安装在底盘，来测量相应的反力。PDS5试样的加工完毕后，装在大底盘上在三坐标加工中心进行了铣削，这种加工中心是由钢铁公司所生产(中压型三号),配备了FANUC-18M公司的数控控制器(0.99型)。用hommelwerket4000设备来测量前机加工前表面的粗糙度,使其可达到1.6微米。图6试验显示了球面磨削加工工艺的设置。一个由Renishaw公司生产的视频触摸触发探头，安装在加工中心上，来测量和确定和原始式样的协调。数控代码所需要的磨球路径由PowerMILL软件产。这些代码经过RS232串口界面，可以传送到装有控制器的数控加工中心上。加工中心加工中心数控机床电脑图6完成了L18型矩阵实验后，表2（PDS5试样光滑表层的粗糙度）总结了光滑表面的粗糙度RA值，计算了每一个L18型矩阵实验的信噪比（S/N）,从而用于方程（1）。通过表2提供的各个数值，可以得到四种不同程度因素的平均信噪比（S/N），在图7中已用图表显示。表2PDS5试样光滑表层的粗糙度实验序号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控制因素信噪比图7控制影响因素控制因素信噪比球面研磨工艺的目标，就是通过确定每一种因子的最佳优化程度值，来使试样光滑表层的表面粗糙度值达到最小。因为−log是一个减函数，我们应当使信噪比（S/N）达到最大。因此，我们能够确定每一种因子的最优程度使得η的值达到最大。因此基于这个点阵式实验的最优转速应该是18000RPM，如表3（优化组合球面研磨参数）所示。表3优化组合球面研磨参数因素水平白色氧化铝50mm/min20μm18000rpm从田口矩阵实验获得的球面研磨优化参数，适用于曲面光滑的模具，从而改善表面的粗糙度。选择香水瓶为一个测试载体。对于被测物体的模具数控加工中心，由PowerMILL软件来模拟测试。经过精铣，通过使用从田口矩阵实验获得的球面研磨优化参数，模具表面进一步光滑。紧接着,使用打磨抛光的最佳参数，来对光滑曲面进行抛光工艺，进一步改善了被测物体的表面粗糙度。(见图9)。模具内部的表面粗糙度用hommelwerket4000设备来测量。模具内部的表面粗糙度RA的平均值为2.15微米，光滑表面粗糙度RA的平均值为0.45微米，抛光表面粗糙度RA的平均值为0.07微米。被测物体的光滑表面的粗糙度改善了：(2.15-0.45)/2.15=79.1％，抛光表面的粗糙度改善了：(2.15-0.07)/2.15=96.7％。抛光表面抛光表面Ra=0.07μm内部表面Ra=2.15μm光滑表面Ra=0.45μm图8被测物体表面粗糙五、结论在这项工作中,对注塑模具的曲面进行了自动球面研磨与球面抛光加工，并将其工艺最佳参数成功地运用到加工中心