刀具磨损及其寿命.docx

刀具磨损及其寿命.docx

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刀具磨损及其寿命

tippedtool（硬质合金刀）toolbits（车刀）Toolwear

FromWikipedia,thefreeencyclopedia

Toolwear describesthegradualfailureofcuttingtoolsduetoregularoperation.Itisatermoftenassociatedwith tippedtools, toolbits,or drillbits thatareusedwith machinetools.

刀具磨损是用来描述刀具在正常加工过程中的一种逐渐失效的形似。

主要是用以描述硬质合金刀，车刀和钻铣刀等的逐渐失效的术语。

Typesofwearinclude:

∙flankwear inwhichtheportionofthetoolincontactwiththefinishedparterodes.CanbedescribedusingtheToolLifeExpectancyequation.

∙刀具的侧面/后刀面磨损是刀具和工件已切削完的部分接触磨损中的一部分，可以用刀具寿命公式表示。

∙craterwear inwhichcontactwithchipserodestherakeface.Thisissomewhatnormalfortoolwear,anddoesnotseriouslydegradetheuseofatooluntilitbecomesseriousenoughtocauseacuttingedgefailure.

∙剥落磨损或（前刀面磨损/月牙洼磨损）是由于和切屑相接处而磨损出现的一个凹坑（月牙洼），月牙洼和切削刃之间有一小的棱边，在磨损过程中月牙洼逐渐扩大使得棱边逐渐变窄，切削刃的强度大为增加，极易导致崩刀现象。

Canbecausedbyspindlespeedthatistooloworafeedratethatistoohigh.In orthogonal cuttingthistypicallyoccurswherethetooltemperatureishighest.Craterwearoccursapproximatelyataheightequalingthecuttingdepthofthematerial.Craterweardepth~t0 t0=cuttingdepth

主轴转速较低或进给速度较高的时候容易引起前刀面的磨损。

前刀面的磨损经常发生在切削温度较高的地方，它的磨损可以近似的用一个温度和切深公式表示。

∙built-upedge inwhichmaterialbeingmachinedbuildsuponthecuttingedge.Somematerials（notably aluminum and copper）haveatendencyto anneal themselvestothecuttingedgeofatool.Itoccursmostfrequentlyonsoftermetals,withalowermeltingpoint.Itcanbepreventedbyincreasingcuttingspeedsandusinglubricant.Whendrillingitcanbenoticedasalternatingdarkandshinyrings.

切削瘤/积屑瘤磨损主要发生在低速切削软材料时发生的。

可以通过提高切削速度和使用润滑剂来抑制。

∙glazing occurson grindingwheels,andoccurswhentheexposed abrasive becomesdulled.Itisnoticeableasasheenwhilethewheelisinmotion.

∙edgewear,indrills,referstoweartotheouteredgeofa drillbit aroundthecuttingfacecausedbyexcessivecuttingspeed.Itextendsdownthedrillflutes,andrequiresalargevolumeofmaterialtoberemovedfromthedrillbitbeforeitcanbecorrected.

边缘磨损，主要发生在钻削中。

EffectsofToolWear[edit]

SomeGeneraleffectsoftoolwearinclude:

∙increasedcuttingforces

∙increasedcuttingtemperatures

∙poorsurfacefinish

∙decreasedaccuracyoffinishedpart

∙Mayleadtotoolbreakage

∙Causeschangeintoolgeometry

Reductionintoolwearcanbeaccomplishedbyusing lubricants and coolants whilemachining.Thesereducefrictionandtemperature,thusreducingthetoolwear.

刀具磨损会增加切削力和切削温度，降低加工精度，增加工件的粗糙度，严重的还会引起断刀和加工变形等。

可以通过使用润滑剂和冷却器来抑制刀具的具的磨损。

ToolLifeExpectancy[edit]

The Taylor'sEquationforToolLifeExpectancy[1] providesagoodapproximation.

Amoregeneralformoftheequationis

where

∙

=cuttingspeed

∙T=toollife

∙D=depthofcut

∙S=feedrate

∙x and y aredeterminedexperimentally

∙n and C areconstantsfoundbyexperimentationorpublisheddata;theyarepropertiesoftoolmaterial,workpieceandfeedrate.

TemperatureConsiderations[edit]

Temperaturegradientoftool,workpieceandchipduringorthogonalcutting.Ascaneasilybeseen,heatisremovedfromtheworkpieceandthetooltothechip.Craterwearoccursaroundthe720degreeareaofthetool.

Athightemperaturezonescraterwearoccurs.Thehighesttemperatureofthetoolcanexceed700°Candoccursattherakefacewhereasthelowesttemperaturecanbe500°Corlowerdependingonthetool...

EnergyConsiderations[edit]

Energy comesintheformofheatfromtool friction.Itisareasonableassumptionthat80%ofenergyfromcuttingiscarriedawayinthechip.Ifnotforthistheworkpieceandthetoolwouldbemuchhotterthanwhatisexperienced.Thetoolandtheworkpieceeachcarryapproximately10%oftheenergy.Thepercentofenergycarriedawayinthechipincreasesasthespeedofthecuttingoperationincreases.Thissomewhatoffsetsthetoolwearfromincreasedcuttingspeeds.Infact,ifnotfortheenergytakenawayinthechipincreasingascuttingspeedisincreased;thetoolwouldwearmorequicklythanisfound.

温度分布合理的假设是，切屑带走了80%的热量刀具和工件各吸收10%的热量；当切削速度增加时，切屑带走的温度所占的比重更大，这刚好弥补了速度增加时对刀具的磨损，否则速度增加时刀具的磨损将更快。

Multi-CriteriaofMachiningOperation[edit]

MalakootiandDeviprasad（1989）introducedthemulti-criteriametalcuttingproblemwherethecriteriacouldbecostperpart,productiontimeperpart,andqualityofsurface.Also,Malakootietal.（1990）proposedamethodtorankthematerialsintermsofmachinability.Malakooti（2013）presentscomprehensivediscussionabouttoollifeanditsmulti-criteriaproblem.Asasexampleobjectivescanbeminimizingof Totalcost （whichcanbemeasuredbythetotalcostofreplacingalltoolsduringaproductionperiod）,maximizingof Productivity （whichcanbemeasuredbythetotalnumberofpartsproducedperperiod）,andmaximizingof qualityofcutting.

Seealso[edit]

∙machinetool

∙toolbit

∙tippedtool

∙drillbit

∙drillpress

∙honing

∙cutting

References[edit]

1.Jumpup^ Taylor,F.W.,OntheArtofCuttingMetals,AmericansocietyofMechanicalEngineers1906,paragraph700andparagraph718

∙Malakooti,B;Deviprasad,J（1989）."AnInteractiveMultipleCriteriaApproachforParameterSelectioninMetalCutting".OperationsResearch37（5）:

805-818.

∙S.KalpakjianandS.R.Schmidt. ManufacturingEngineeringandTechnology.2000,PrenticeHall,UpperSaddleRiver,NJ.

∙S.KalpakjianandS.R.Schmidt. ManufacturingProcessesforEngineeringMaterials.2002,PrenticeHall,UpperSaddleRiver,NJ.

∙K.Kadirgamaetal.2011,"ToolLifeandWearMechanism""http:

//umpir.ump.edu.my/2230/"

∙Malakooti,B.（2013）.OperationsandProductionSystemswithMultipleObjectives.JohnWiley&Sons

∙Malakooti,B.,Wang,J.,&Tandler,E.C.（1990）."Asensor-basedacceleratedapproachformulti-attributemachinabilityandtoollifeevaluation".TheInternationalJournalofProductionResearch,28（12）,2373-2392.

Externallinks[edit]

∙ToolWearPredictionandVerificationinOrthogonalCutting

∙ManufacturingProcessEducationalWebsite

∙InformationPageonGundrillingtoolwear

∙StudyoftoolwearandsurfaceroughnessinmachiningofhomogenisedSiC-preinforcedaluminiummetalmatrixcomposite

1.Vb是磨损量，T是刀具使用时间，以分钟为单位，Vc是进给速度。

0.3是定义的失效标准，磨损量达到0.3mm报废。

这是所谓Taylor刀具寿命理论

Theoptimalcutting-parameterselectionofheavycutting

processinsidemillingforSUS304stainlesssteel

ChangChing-Kao&H.S.L

Basically,metalremovalrateandtoollifearecorrelatedwiththecuttingparameterssuchasspindlespeed,feedpertooth,radialdepthofcutandaxialdepthofcut.

Taguchimethodisoneofthesolutionsforparameterdesignandexperimentalplanning田口方法是加工参数优化的一种方法Itanalyzestheinfluenceofparametervariationtoperformancecharacter-istics.Thereby,anoptimalresultcanbeobtainedsothatthesensitivityofperformancecharacteristicsrespecttoparam-etervariation.通过参数变化的影响程度++++greyrelationalanalysisandfuzzylogicstoacquirethisoptimaldesign.The此外灰箱理论和模糊算法也可以用以计算参数优化算法。

greyrelationalgradeisobtainedtoevaluatethemultipleperformancecharacteristics.

Thetheoryoffuzzylogics,initiatedbyZadehin1965

[21]hasproventobeusefulfordealingwithuncertainandvagueinformation,andhasbeensuccessfullyappliedinmanyresearchfields[20,22–25].Thisissuitabletodealwiththeoptimizationprobleminthisstudy,sincethedefinitionofperformancecharacteristicssuchaslower-the-better,higher-the-better,andnominal-the-bettercontainsacertaindegreeofuncertaintyandvagueness.

Toollifeandmetalremovalrateareinclosecorrelationwiththecuttingparameterssuchasspindlespeed,feedpertooth,axialdepthofcut,andradialdepthofcut,thatareregardedascontrollablefactorsinthestudy.Eachfactorissettothreelevels.According

加工参数spindlespeedof2000rpm,feedpertoothof0.074mm/t,axialdepthofcutof15mmandradialdepthofcutof0.7mm.

模糊算法中忽略了因素不同隶属度之间的关系。

Inthefuzzylogicanalysis,thefuzzifierusesmembershipfunctionstofuzzifythegreyrelationalcoeffi-cientfirst.模糊逻辑是用隶属度函数将数值模糊化的Next,theinferenceengineperformsafuzzyreasoningonfuzzyrulestogenerateafuzzyvalue.Finally,thedefuzzifierconvertsthefuzzyvalueintoagrey-fuzzyreasoninggrade.

Theyareconvertedintolinguisticfuzzysubsetsusingmembershipfunctionsofatriangleform,thatareshowninFig.3,andareuniformlyassignedintothreefuzzysubsets—small（S）,medium（M）,andlarge（L）grade.隶属度函数将模糊集合转换成三角形式

Thefuzzyinferenceengineisthekernelofafuzzysystem.Itcansolveaproblembysimulatingthethinkinganddecisionpatternofhumanbeingusingapproximateorfuzzyreasoning.模糊推理机理是模糊系统的核心他可以模仿人的大脑用近似或模糊机理进行决断。

Finally,adefuzzificationmethod,calledthecenter-of-gravitymethod[18],isutilizedheretotransformthefuzzyinferenceoutputmCointoanon-fuzzyvalue将输出的模糊集合用中心重力方法去模糊化得到想要的结果

BasedonTable7,theparameterswiththebestlevelareV1,F3,Da3,andDr3duetotheirhighgrey-fuzzyreasoninggrade.TherankinginTable7demonstratesthattheparameterV（spindlespeed）,Dr（radialdepthofcut）,andDa（axialdepthofcut）haverelativelystrongimpactsonthemultipleperformancecharacteristics,whiletheparameterF（feedpertooth）hasrelativelyweakimpact.每齿进给率相对于轴向切深和径向切深以及主轴转速对加工性能的影响相对较小。

Progressivetoolflankwearmonitoringbyapplyingdiscretewavelettransformonturnedsurfaceimages

SamikDuttaa,SurjyaK.Palb,⇑,RanjanSena

用discretewavelettransform离散小波变换，处理加工表面的微尺寸图片

AEsensorsaredisadvanta-geousforprogressivemonitoringoftoolwearduetodiffi-cultyinpositioning,complexcalibrationandsensitivenesstonoiseofmachining.声发射传感器，由于对定位、噪声的敏感度以及复杂的校准导致不是与刀具的磨损监测Powersensorsaremoresensitiveto