《数字化协同制造综合实训》课件-任务1-钻孔的基本编程(英文)_第1页
《数字化协同制造综合实训》课件-任务1-钻孔的基本编程(英文)_第2页
《数字化协同制造综合实训》课件-任务1-钻孔的基本编程(英文)_第3页
《数字化协同制造综合实训》课件-任务1-钻孔的基本编程(英文)_第4页
《数字化协同制造综合实训》课件-任务1-钻孔的基本编程(英文)_第5页
已阅读5页,还剩40页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

AseriesoftextbooksformechanicalinnovationplanninginhighervocationaleducationTask1BasicprogrammingfordrillingProject5HoleMachiningLearnthroughthisprojectItenablesstudentstomastertheapplicationofpoint,drillingandreaminginstructionsofCNCmachinetools,andbeabletoindependentlyoperatetheFANUCVDL-600ACNCmillingmachinetocompletedrillingandprocessingofworkpieces.Task1BasicprogrammingofdrillingFirst,thecontentofthetaskFigure5-1-1ProductionPattern(mm)BylearningtodrillthetooltypepeculiarityPreparationofboreholesMachiningprogramTheworkpieceisprocessedaccordingtotherequirementsoftheproductiondrawingFormulateprocessingroutesBeabletouseG-codescorrectlyFigure5-1-1Task1BasicprogrammingofdrillingSecond,themissionobjectives1MastertheoperationstepsoftheFANUCVDL-600AverticalCNCmillingmachine.2AbletocorrectlyuseG-codetoprogramdrilling.3Cultivatestudents'self-directedlearningabilityandteamworkability.4Enhancestudents'interestinlearningandmotivatestudentstoparticipateinpracticalteachingtasks.Task1Basicprogrammingofdrilling3.TaskpreparationPreparationofmaterials100mm×100mm×20mm45#steel.PreparationofequipmentandtoolsFANUCVDL-600AVerticalCNCMillingMachine,HydraulicVice.KnifepreparationCenterdrills,twistdrills,reamers.GagepreparationVerniercalipers,edgefinders.AuxiliarytoolsHorns,visewrenches,copperrods.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.AdrillbitOrientationAxialforceCuttingedgeFeaturesofthedrillbitusedinCNCmillingmachinedrillingThetoolusedindrillingisadrillbit,whichisusedtopunchholesintheworkpiece.Drillbitsaredividedintohigh-speedsteeldrillsandcementedcarbidedrillsaccordingtothematerial;Drillbitscanbedividedintoordinarydrills,shallowholedrills,deepholedrills,centeringdrills,etc.Task1BasicprogrammingofdrillingFourth,knowledgelinking(1)Cuttingedge1.AdrillbitThetwocuttingedgesareinasymmetricalposition,theradialforcescanceleachotherout,andnobendingoccursintheaxialdirection,asshowninFigure5-1-2.drillbitFigure5-1-2CuttingedgeTask1BasicprogrammingofdrillingFourth,knowledgelinking(2)Axialforce1.AdrillbitTheaxialforceactsontheaxialdirectionofthedrillbit,asshowninFigure5-1-3.AxialforceFigure5-1-3AxialforceA=AxialforceB=FeedTask1BasicprogrammingofdrillingFourth,knowledgelinking(3)Orientation1.AdrillbitThedrillbitisguidedforwardbythemachinedhole,asshowninFigure5-1-4.OrientationFigure5-1-4OrientationTask1BasicprogrammingofdrillingFourth,knowledgelinking1.AdrillbitThediameterofthedrillbitisnotverylarge,whichallowsforefficientmachiningandchipevacuation.Eachpartofthedrillbithasdifferentfunctions,whichisintroducedwithatwistdrillasanexample.Task1BasicprogrammingofdrillingFourth,knowledgelinking(1)Groovelength1.AdrillbitGroovelengthGroovelengthAffectstheaccuracyoftheholeandthelifeofthedrillbitThegroovelengthisdeterminedbythedepthoftheholeandtheamountofheavygrinding,thegroovelengthincreases,thecorrespondingdrillbitlengthincreases,andtherigidityofthedrillbititselfdecreases.Thedrillbitwithlowrigiditywilloscillatestronglywhencuttingintotheworkpiece,andthecenterofrotationcannotbefixed,whichwillreducetheaccuracyoftheholeandaffectthelifeofthedrillbit.Figure5-1-5GroovelengthItisgenerallyadvisabletochooseadrillwithasshortagroovelengthaspossibleTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(2)HelixangleFigure5-1-6HelixAngleHelixangleItistheangleofinclinationofthespiralgrooveofthedrillbitrelativetotheaxialdirection,andthehelixangleoftheouterperipheryofthedrillbitisequaltotherakeangle.Ingeneral,thehelixangleisabout30°Itiscalledwhenitislessthan30°WeakhelixItiscalledwhenitisgreaterthan30°StrongspiralTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(2)HelixangleWeakaugerbitsThelengthofthehelixisshort,andthechipevacuationperformanceisgood,buttherakeangleissmall,andthecuttingresistanceisincreased.StrongaugerbitsTherakeangleislarge,thecuttingresistanceisreduced,andthecuttingedgecornerpartissharp,whichispronetochippingandbreakage.Figure5-1-6HelixAngleTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(2)HelixangleWorkpiecematerialHelixangleCastiron,steel(280HBorless)28°~32°Steel(281HBormore)15°~30°Lightalloy,stainlesssteel10°~42°Dependingontheworkpiecematerial,themostsuitablehelixangleangleisalsodifferent,asshowninTable5-1-1.Table5-1-1HelixanglesforvariousworkpiecematerialsTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(3)CorethicknessanddrilltaperFigure5-1-7CorethicknessanddrilltaperCorethickness,coretaperandgroovewidthDeterminestheshapeofthedrillprofileInthecaseofalargecorethickness,therigidityofthedrillbitcanbeimproved,butthegrooveareaisreduced,chipevacuationbecomesdifficult,andtheaxialforceofthecuttingresistancebecomeslarger,whichhasanimpactontheoveralldrilling.Thehigh-speedsteeldrillbitisusedonthedrillingmachine,andthecorethicknessis10%~20%ofthediameterofthedrillbit,andtheproportionofthedrillbitwithasmalldiameterislarger,andtheproportionwilldecreasewiththeincreaseofthediameterofthedrillbit.HSSdrillbitshavehightoughness,sochipevacuationisapriority.Andthehigh-speed,high-efficiencycarbidedrillbitusedonthehigh-rigidityandhigh-powerCNCmillingmachinehasacorethicknessofupto20%~30%ofthediameter,whichistoimprovetherigidityofthedrillbit,sothatthefeedratecanbeincreasedandthechipscanbebroken.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(3)CorethicknessanddrilltaperFigure5-1-7CorethicknessanddrilltaperAsthecorethicknessincreases,thetransverseedgeofthetopcorethicknessbecomeslonger,andtheextrusionrangeexpands,andtheaxialforceincreases.CoretaperisusedforHSSbitsordeepholebitswiththinnercorethickness,whichcanimprovetherigidityofthedrillbits.Ingeneral,thecoretaperofa100mmdiameterdrillbitiswithin2mm,andifthecoreconeistoolarge,itwillleadtodifficultyinchipevacuation.ThecorethicknessanddrillcoretaperaremadeofDrillbitmaterialWorkpiecematerialtobesureTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(4)TopangleFigure5-1-8TopAngleThesizeoftheapexanglehasaneffectonthechipthicknessFeedfinthecaseofacertainamountWhentheapexangleissmall,thecuttingamounthofthecuttingedgeintheverticaldirection

becomessmaller;Whentheapexangleislarge,thestockremovalh'thickensandthereforethechipthicknessincreases.Thewaytopreventchipsfromgettingtangledaroundthedrillbitistoincreasethetopanglesothatthechipsareeasytobreak.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(5)BladebandwidthItisappropriatetosetthebladewidthat6%~10%ofthedrilldiameter.Figure5-1-9FlutebandwidthOrientationThedrillbithas:Inordertoimprovetheroundnessandroughnessofthemachininghole,therearealsodrillbitsthatincreasethewidthofthecuttingedgetoimprovetherollerpolishingeffect.frictionalforceTask1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(6)InvertedconeFigure5-1-10InvertedconeInthecuttingprocess,inordertoreducethefrictionbetweentheholewallandtheouterperipheryofthedrillbit,aninvertedconeisprovidedontheouterdiameterofthedrillbit.Theinvertedconeissometimesexpressedintermsofangles,butingeneralitisexpressedintermsofthereductionofthediameterrelativetothelengthofthegroove.Whenmachiningsoftmaterialssuchasaluminumalloyordifficult-to-cutmaterialssuchasstainlesssteel,thediameteroftheholeissmallerthanthediameterofthedrillbit,andtheincreaseinthebackconecaneffectivelypreventthetorquefromrising.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(6)InvertedconeFigure5-1-10InvertedconeIftheinvertedconeistoosmall,theshrinkageoftheholewillmakethedrillbitbeboundandeasytobreak;Iftheinvertedconeistoolarge,itwillleadtoadecreaseintheconductivityandtheoccurrenceofadeflectionhole.Theinvertedconeshouldbesetinasuitablerangeaccordingtothedifferencebetweenthedrillbitmaterialandtheworkpiecematerial.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(7)FrontangleFigure5-1-11FrontangleTherakeangle(axial)ofthedrillbitisrelatedtothehelixangleThelargerthehelixangleThelargertherakeangleInfact,thesizeoftherakeangleisaffectedbythepositionofthecuttingedge,andthehelixangleisequaltotherakeangleintheouterperipheryofthedrill.Therakeangleθ2(helixangle)oftheouterperipheryofthecuttingedgecanbefoundusingtheformulainFigure5-1-11.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(8)RearcornerFigure5-1-12RearAngleInordernottohinderthefeedmovementofthedrillbit,areliefangleisprovidedontheflankfaceofthecuttingedge.Thedrillisrotatedfor1rotationandthecuttingedgeadvancesaxiallyf.Ifthereliefangleislessthanorequaltotheangleθ1formedbytheoutermostperipheryofthedrillbitwiththefeed,theflankfaceofthedrillbitwillcomeintocontactwiththeworkpieceandtheaxialforcewillrisesharply.Therefore,theminimumreliefanglemustbegreaterthanthevalueobtainedbytheformulainFigure5-1-12,andthereliefangleisgenerallysetat7°~15°.Ifthereliefangleisincreased,thecontactbetweentheworkpieceandtheflanksurfacewillbereduced,andtheaxialforcewillbereduced,butitiseasytochippingandbreakage.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(9)ShovelbackdepthFigure5-1-13ShovelbackdepthTheshovelbackisagapof0.2~0.5mmsettoavoidthefrictionbetweenthedrillbitandtheworkpiece.Thebackdepthissettocontroltheincreaseintorqueduetotheincreaseinbeltwidthwhenthebeltispartiallyworn,andalsotoconcentratethecoolantonthecuttingedge.Thebackdepthofathinnerdrillbitiscloselyrelatedtotherigidityofthedrillbitandthereforehasasignificantimpactontoollife.Task1BasicprogrammingofdrillingFourth,knowledgelinking1.Adrillbit(10)GroovewidthFigure5-1-14SlotwidthThegroovewidthofthedrillbitItissetonthepremiseoffullyconsideringthestrengthofthedrillbitandthehandlingofchipsItsequilibriumiscalledthegroovewidthratio,whichisexpressedbytheratioofthebladewidthθ1atthetipofthedrillbit

tothegroovewidthθ2.Thegroovewidthratioisgenerally1~1.2,andthegroovewidthofthedrillbitthatattachesimportancetochipremovalperformanceisrelativelylarge,andthegroovewidthofthedrillbitthatattachesimportancetorigidityisrelativelysmall.Task1BasicprogrammingofdrillingFourth,knowledgelinking2.HoleprocessinginstructionsIfmultipleidenticalholesaremachinedonthesamesurface,severalidenticalmachiningsequencesneedtobecompleted;IfwrittenusingcommonprogramminginstructionsTheprocedureofholeprocessingisverytroublesome;TheprogrammingcanbegreatlysimplifiedbyusingtheHoleMakingFixedCyclefunctioninstructions.Thesequentialactionsrequiredtobecompletedinmachiningprocessessuchasdrilling,boring,reaming,deepholedrilling,andtappingholesareverytypical;Task1BasicprogrammingofdrillingFourth,knowledgelinking2.HoleprocessinginstructionsTable5-1-2showsthefixedcyclefunctionforholemachiningoftheFANUCCNCsystem,including12fixedcyclefunctioninstructionsand1unfixedcyclefunctioncommand(G80).G-codeHolemakingaction(-Zdirection)ActionatthebottomoftheholeToolreturnmethod(+Zdirection)useG73Intermittentfeeding—fastHigh-speedpeckingdrillingG74CuttingfeedPause—ThespindlerotatesforwardCuttingfeedTaptheleft-handthreadedholeG76CuttingfeedSpindlequasi-stop—tooldisplacementfastFineboringG80———CancelthefixedloopG81Cuttingfeed—fastDrilling,drillingcenterholesG82CuttingfeedTimeoutfastDrilling,countersinking,boringsteppedholes,holechamferingG83Intermittentfeeding—fastPeckdrillingG84CuttingfeedPause—ThespindleisreversedCuttingfeedTaptheright-handthreadedholeG85Cuttingfeed—CuttingfeedFineboring,reamingG86CuttingfeedTimeoutfastBoringG87CuttingfeedTimeoutfastAnti-boringG88CuttingfeedPause—ThespindlestopsManualBoringG89CuttingfeedTimeoutCuttingfeedFineboringsteppedholesTask1BasicprogrammingofdrillingFourth,knowledgelinking2.HoleprocessinginstructionsFigure5-1-15ThecompositionofthefixedcycleThecompositionofthefixedcycleThefixedcycle,asshowninFigure5-1-15,consistsof6actionsAction1:X,Yaxispositioning,sothatthetoolisquicklypositionedtothepositionofthehole.Action2:TheZ-axisisquicklymovedtotheRplane.Action3:Machiningthehole,performingthemachiningactionoftheholeintheformofcuttingfeed.Action4:Actionsatthebottomofthehole,includingpause,spindlequasi-stop,tooldisplacement,etc.Action5:ReturntotheR-plane,continuemachiningthehole,andreturntotheR-planewhenitissafetomovethetool.Action6:Quicklyreturntotheinitialplane,generallyreturningtotheinitialplaneafteralltheholesaremade.(1)ThecompositionofthefixedcycleTask1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(2)Fixed-loopinstructionformatG90andG91aredatainputformatinstructions,G90istheabsolutecoordinate,andG91istheincrementalcoordinate;G98andG99arethepositioninstructionsforthetoolreturn,G98istheinitialplaneofthetoolreturn,andG99isthetoolreturnRplane(theRplaneisalsocalledthereferenceplane,whichisgenerally2~5mmawayfromtheuppersurfaceoftheworkpiece);G73~G89istheinstructionfortheprocessingmethodofthehole(Table5-1-2);"X"and"Y"arethecoordinatevaluesofXandYfortheplanepoint,whichcanbeusedasabsolutecoordinatevaluesorincrementalcoordinatevalues;"Z"istheZcoordinatevalueofthetoolreachingthebottomofthehole,whichrepresentsthedistancefromthecoordinateorigintotheZpointatthebottomoftheholewhenusingabsolutecoordinates,andthedistancefromtheRplanetotheZpointatthebottomoftheholewhenusingincrementalcoordinates;Fixed-loopinstructionformatG90(G91)G98(G99)G73G89X_Y_Z_R_Q_P_F_L_;Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(2)Fixed-loopinstructionformatFixed-loopinstructionformatG90(G91)G98(G99)G73G89X_Y_Z_R_Q_P_F_L_;"R"istheZcoordinatevalueoftheRplane,whichrepresentsthedistancefromthecoordinateorigintotheRplanewhenusingabsolutecoordinates,andthedistancefromtheinitialplanetotheRplanewhenusingincrementalcoordinates."Q"isthedepthofeachfeedspecifiedintheG73andG83commands,andtheamountofdisplacementofthetoolisspecifiedintheG76andG87commands,giveninincrements;"P"istheresidencetimeofthetoolatthebottomofthehole;"F"isthecuttingfeedrate;"L"isafixednumberofcycles,whichisperformedonlyonceifnotspecified.Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(2)Fixed-loopinstructionformatOncethefixedcyclemachiningmethodisspecified,itremainsunchangedduringthemachiningprocessuntilotherholefixedcycleprocessingmethodsarespecifiedortheG80instructioncancelsthefixedcycle;Whenmachiningthesamehole,themachiningmethodisperformedcontinuously,andthereisnoneedtoreassignthemachiningmethodforeachhole.Whenusingtheholefixedcycleprocessingfunction,allthedatarequiredforthecycleprocessingholeshouldbegivenfirst,andonlythefunctionwordsthatneedtobechangedshouldbegiveninthefixedcycleprocess.IfG00,G01,G02,andG03areusedintheprogram,thefixedcycleprocessingmethodanditsprocessingdataareallcanceled.Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(3)CommonlyusedholefixedcycleprocessinginstructionformatandapplicationexamplesI..Instructionformatfordrilling,drillingcenterholefixedcycleinstructionG81:G90G98(G99)G81X_Y_Z_R_F_;Thespindlerotatesforward,ontheinitialplane,thecutterquicklyreachesthepositionoftheholeforpositioning,quicklyreachestheRplane,startsfromtheRplaneandthetoolmovesdownwardatthefeedratetodrillthehole,andafterreachingthebottomofthehole,itquicklyreturnstotheRplane(G99)ortheinitialplane(G98),andthereisnoholebottomaction,asshowninFigure5-1-16.Illustrate:Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(3)CommonlyusedholefixedcycleprocessinginstructionformatandapplicationexamplesII..Drilling,countersinking,boring,steppedholes,orificechamferingfixedcycleinstructionsG82commandformat:G90G98(G99)G82X_Y_Z_R_P_F_;ThemaindifferencefromG81isthatthereisadwellatthebottomoftheholeinG82,andthedwelltimeisgivenbyaddressP;OtheractionsarethesameastheG81.Thisinstructionismainlyusedformachiningblindholesorsteppedholes,etc.,toimprovetheaccuracyofthebottomofthehole.Illustrate:Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(3)CommonlyusedholefixedcycleprocessinginstructionformatandapplicationexamplesIII..PeckDrillingFixedCycleInstructionG83InstructionFormat:

G90G98(G99)G83X_Y_Z_R_Q_F_;ThemaindifferencewithG81isthatG83isusedfordeepholemachining,usingpeckingdrilling(intermittentfeed)tofacilitatechipevacuation,returningtotheRplaneaftereachdrillingdistanceofQ,distheamountofcutter,itsvalueissetbytheinternalparametersoftheCNCmillingmachinesystem,andthedistanceofthelastdrillingislessthanorequaltoQ,asshowninFigure5-1-17.Illustrate:Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(3)CommonlyusedholefixedcycleprocessinginstructionformatandapplicationexamplesIV..TappingtherightthreadedholetofixtheloopinstructionG84Instructionformat:G90G98(G99)G84X_Y_Z_R_F_;ThemaindifferencewiththeG81isthatthespindleisforwardwhentheG84tapstherightthread,andwhenthespindleexitsaftertappingtherightthread,thespindlereversesandreturnstotheRplane(G99)ortheinitialplane(G98)atthefeedrate.Thetappingprocessrequiresthatthefeedspeedisstrictlyproportionaltothespindlespeed,anditsproportionalityfactoristhepitchofthethread,thatis,thefeedspeed=thepitchofthethread×thespindlespeed,sotheprogrammingrequiresthecalculationofthefeedrateaccordingtothespindlespeed,asshowninFigure5-1-18.Illustrate:Task1BasicprogrammingofdrillingFourth,knowledgelinking2.Holeprocessinginstructions(3)CommonlyusedholefixedcycleprocessinginstructionformatandapplicationexamplesV.Fineboring,reamingfixedcycleinstructionG85instructionformat:G90G98(G99)G85X_Y_Z_R_F_;Thespindlerotatesforward,intheinitialplane,thecutterquicklyarrivesatthepositionoftheholepositioning,quicklyreachestheRplane,startsfromtheRplaneandthetoolmovesdownwardatthefeedratetodrillthehole,andafterreachingthebottomofthehole,itreturnstotheRplane(G99)ortheinitialplane(G98)atthefeedrate,withoutthebottomoftheholeaction,asshowninFigure5-1-19.Illustrate:Task1Basicprogrammingofdrilling5.Tasksteps1.StudythedrawingsReadthedrawingsandpreliminarilycheckthedimensionsandrequirementsofthedrawings.Task1Basicprogrammingofdrilling5.Tasksteps2.FormulateprocessingtechnologyEstablishtheworkpiececoordinatesystemaccordingtothedrawingandsimplifiedprogramming;ThisisshowninFigure5-1-20.Task1Basicprogrammingofdrilling5.Tasksteps2.FormulateprocessingtechnologyFortoolselection,thistaskusesaφ3mmcompositecenterdrillholeandaφ6mmdiameterdrillbittodrillthehole,asshowninTable5-1-3.CutternumberThenameofthecutterSpindlespeedFeedrateT1φ3mmcenterdrillS1000F100T2φ6mmdrillbitS900F50Table5-1-3ToolCardsTask1Basicprogrammingofdrilling5.Tasksteps2.FormulateprocessingtechnologyForbasispointcalculation,seeTable5-1-4.serialnumberXYremark1-150

2150

Table5-1-4basispointcalculationsTask1Basicprogrammingofdrilling5.Tasksteps2.FormulateprocessingtechnologyDeterminetheoriginoftheworkpiececoordinatesystemandtheroutingroute,T1is1→2,T2is1→2.Task1Basicprogrammingofdrilling5.Tasksteps2.FormulateprocessingtechnologyMachiningprogramexegesisO1111;ThenameofthemainprogramG90G17G21G40G49G80;initializeG28G91Z0;TheZ-axisisbacktothereferencepointG54G90G00X0Y0;ThetoolmovesquicklytotheworkpiececenterpointM03S1000;Thespindlerotatesforwardataspeedof1000r/minZ100;ThetoolmovesquicklytoasafesurfaceG98G81X-15Y0Z-1R1F100;Thecuttermovesquicklytohole1anddrillstoadepthof-1mmataspeedofF100X15;Thecuttermovesquicklytohole2anddrillstoadepthof-1mmataspeedofF100M05;ThespindlestopsM30;EndofprogramTable5-1-5ReferenceProcedure(T1=φ3mmCenterDrill)WritetheCNCmachiningprogram,seeTable5-1-5andTable5-1-6forreference.Task1Basicpro

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论