NumericalControlSystemThenumericalcontrolsystemisthedigitalcontrolsystemabbreviation.Byearlyiscomposedofhardwarecircuitiscalledhardwarenumericalcontrol(HardNC),after1970,hardwarecircuitcomponentsgraduallyinsteadbythecomputercalledforcomputernumericalcontrolsystem.Computerizednumericalcontrolsystemisasystemthatisusecomputercontrolprocessingfunctiontoachievenumericalcontrolsystem.CNCsystemaccordingtothecomputermemorystoredinthecontrolprogramexecutionpartorall,numericalcontrolfunction,andisequippedwithinterfacecircuitandservodrivethespecialcomputersystem.CNCsystemconsistsofNCprogram,inputdevices;outputdevices,computernumericalcontrolequipment(CNCequipment),programmablelogiccontrollers(PLC),thespindleandfeeddrive(servo)drive(includingdetectiondevices)andsoon.ThecoreofCNCsystemisequipment.ByusingthecomputersystemwiththefunctionofsoftwareandPLCinsteadofthetraditionalmachineelectricdevicetomakethesystemlogiccontrolmorecompact,itsflexibilityandversatility,reliabilitybecomemorebetter,easytoimplementcomplexnumericalcontrolfunction,useandmaintenancecanbemoreconvenient,anditalsohasconnectedandsuperordinationmachineandtheremotecommunicationfunction.Atpresent,thenumericalcontrolsystemhasvarietyofdifferentforms;compositionstructurehasitsowncharacteristics.Thesestructuralfeaturesfromthebasicrequirementsoftheinitialsystemdesignandengineeringdesignideas.Forexample,thecontrolsystemofpointandcontinuouspathcontrolsystemshavedifferentrequirements.FortheTsystemandtheMsystem,therearealsoverydifferent,theformerappliestorotarypartprocessing,thelattersuitableforspecial-shapedtheaxiallysymmetricalpartsprocessing.Fordifferentmanufacturers,basedonhistoricaldevelopmentfactorsandvarytheircomplexfactors,mayalsobethinkinginthedesignisdifferent.Forexample,theUnitedStatesDynapathsystemusesasmallplateforeasyreplacementandflexiblecombinationoftheboard;whileJapanFANUCsystemisalargeplatestructuretendstomakethesystemworkinfavorofreliability,makethesystemMTBFratecontinuestoincrease.However,nomatterwhatkindofsystem,theirbasicprincipleandstructureareverysimilar.Thenumericalcontrolsystemgenerallyconsistsofthreemajorcomponents,namelythecontrolsystem,servosystemandpositionmeasuringsystem.Controlproceduresbyinterpolationoperationworkpiece,issuecontrolinstructionstotheservodrivesystem;servodrivesystemcontrolinstructionsamplifiedbytheservomotor-drivenmechanicalmovementrequired;measurementsystemdetectsthemovementofmechanicalpositionorspeed,andfeedbacktothecontrolsystem,tomodifythecontrolinstructions.Thesethreepartscombinetoformacompleteclosed-loopcontroloftheCNCsystem.Controlsystemmainlyconsistsofbus,CPU,powersupply,memory,operatingpanelanddisplay,positioncontrolunit,programmablelogiccontrollercontrolunitanddatainput/outputinterfaceandsoon.ThelatestgenerationofCNCsystemalsoincludesacommunicationunit;itcancompletetheCNC,PLC'sinternaldatacommunicationsandexternalhigh-ordernetworks.Servodrivesystemincludingservodrivesandmotors.Positionmeasuringsystemismainlyusedgrating,orcirculargratingincrementaldisplacementencoder.CNCsystemhardwarefromtheNCdevice,input/outputdevices,drivesandmachinelogiccontroldevices,electricalcomponents,betweenthefourpartsthroughtheI/Ointerfacetointerconnect.NumericalcontroldeviceisthecoreofCNCsystem,itssoftwareandhardwaretocontroltheimplementationofvariousCNCfunctions.ThehardwarestructureofnodevicebyCNCinstallationsintheprintedcircuitboardwithinfixingpatterncanbedividedintothebigboardstructureandfunctionmodule(smallboard)structure;PressCNCapparatushardwaremanufacturingmode,canbedividedintospecialstructureandpersonalcomputertypestructure;PressCNCapparatusinthenumberofmicroprocessorcanbedividedintosinglemicroprocessorstructureandmanymicroprocessorstructure.(1)LargepanelstructureandfunctiontemplatesstructureLargepanelstructurePanelstructuresCNCsystemCNCequipmentfromthemaincircuitboard,positioncontrolpanels,PCboards,graphicscontrolpanel,additionalI/Oboardandpowersupplyunitandothercomponents.Themaincircuitboardprintedcircuitboardisbig;theothercircuitboardisasmallplate,insertedinthelargeprintedcircuitboardslot.Thisstructureissimilartothestructureofmicro-computer.Functiontemplatesstructure(2)Single-microprocessorstructureandmulct-microprocessorstructureSingle-microprocessorstructureInasingle-microprocessorstructure,onlyamicroprocessortofocusoncontrol,time-sharingdealswiththevarioustasksofCNCequipment.melt-microprocessorstructureWiththeincreaseinnumericalcontrolsystemfunctions,CNCmachinetoolstoimprovetheprocessingspeedofasinglemicroprocessorCNCsystemcannotmeettherequirement;therefore,manyCNCsystemsusesamulti-microprocessorstructure.Ifanumericalcontrolsystemhastwoormoremicroprocessors,eachmicroprocessorviathedatabusorcommunicationtoconnect,sharesystemmemoryandcommonI/Ointerfaces,eachprocessorsharingsystemPartofthework,whichismulti-processorsystems.CNCsoftwareisdividedintoapplicationsoftwareandsystemsoftware.CNCsystemsoftwarefortherealizationofvariousfunctionsoftheCNCsystem,thepreparationofspecialsoftware,alsoknownascontrolsoftware,storedinthecomputerEPROMmemory.CNCSystemsfeatureavarietyofsettingsanddifferentcontrolschemes,andtheirsystemsoftwareinthestructureandsizevarywidely,butgenerallyincludeinputdataprocessingprocedures,computinginterpolationprocedures,speedcontrolprocedures,managementproceduresanddiagnosticprocedures.(1)InputdataprocessingproceduresItreceivesinputpartprogram,thestandardcode,saidprocessinginstructionsanddatadecoding,dataprocessing,accordingtotheprescribedformatforstorage.Somesystemsalsocalculatedtocompensate,orinterpolationoperationandspeedcontrolforpre-computation.Typically,theinputdataprocessingprogram,includinginput,decodinganddataprocessingthreeelements.(2)ComputinginterpolationproceduresCNCworkpieceprocessingsystemaccordingtothedataprovided,suchascurvetype,start,end,etc.operations.Accordingtotheresultsofoperationsweresenttoeachaxisfeedpulse.Thisprocessiscalledinterpolationoperation.FeeddriveservosystemImpulsivetableorbyacorrespondingmovementofthetooltocompletetheproceduralrequirementsoftheprocessingtasks.InterpolationforCNCsystemisthesideoftheoperation,whileprocessing,isatypicalreal-timecontrol,sotheinterpolationdirectlyaffectsthespeedofoperationthemachinefeedrate,andshouldthereforebepossibletoshortencomputationtime,whichisthepreparationofinterpolationComplementsthekeytotheprogram.(3)SpeedcontrolproceduresSpeedcontrolprogramaccordingtothegivenvaluecontrolthespeedofoperationofthefrequencyinterpolation,inordertomaintainapredeterminedfeedrate.Changesinspeedislarge,theneedforautomaticcontrolofaccelerationanddecelerationtoavoidspeeddrivesystemcausedbymutationsinstep.(4)ManagementproceduresManagementproceduresresponsiblefordatainput,dataprocessing,interpolationprocessingservicesoperationsasthevariousproceduresforregulationandmanagement.Managementprocessbutalsoonthepanelcommand,theclocksignal,theinterruptcausedbyfaultsignalsforprocessing.(5)DiagnosticproceduresDiagnosticfeaturesarefoundintherunningsystemfailureinatimelymanner,andthatthetypeoffailure.Youcanalsorunbeforeorafterthefailure,checkthesystemmaincomponents(CPU,memory,interfaces,switches,servosystems,etc.)functionisnormal,andthatthesiteoffailure.MachiningAnymachiningmusthavethreebasicconditions:machiningtools,workpieceandmachiningsports.Machiningtooledgeshouldbe,thematerialmustberigidthantheworkpiece.Differentformsoftoolstructureandcuttingmovementsconstitutedifferentcuttingmethods.Bladewithablade-shapedandhaveafixednumberofmethodsforcuttingtoolsforturning,drilling,boring,milling,planning,broaching,andsawing,etc.;edgeshapeandedgewithnofixednumberofabrasiveorabrasiveCuttingmethodsaregrinding,grinding,honingandpolishing.Machiningisthemostimportantmachinerymanufacturingprocessingmethods.Althoughtheroughimprovemanufacturingprecision,casting,forging,extrusion,powdermetallurgyprocessingapplicationsonwidely,buttoadapttoawiderangeofmachining,andcanachievehighaccuracyandlowsurfaceroughness,inManufacturingstillplaysanimportantroleintheprocess.Cuttingmetalmaterialshavemanyclassifications.Commonarethefollowingthreekinds.Bycuttingprocessfeaturedistinguishingcharacteristicsofthedecisionprocessonthestructureofcuttingtoolsandcuttingtoolsandworkpiecerelativemotionform.Accordingtothetechnicalcharacteristicsofcuttingcanbedividedinto:turning,milling,drilling,boring,reaming,planning,shaping,slotting,broaching,sawing,grinding,grinding,honing,superfinishing,polishing,gearProcessing,thewormprocess,threadprocessing,ultra-precisionmachining,benchandscrapersandsoon.Bymaterialremovalrateandmachiningaccuracydistinctioncanbedividedinto:①rough:withlargedepthofcut,oneorafewtimesbytheknifeawayfromtheworkcutoutmostorallallowances,suchasroughturning,roughplanning,Roughmilling,drillingandsawing,etc.,roughmachiningprecisionhighefficiencylow,generallyusedasapre-processing,andsometimesalsoforfinalprocessing.②Semi-finishing:Generalroughingandfinishingasthemiddlebetweentheprocess,buttheworkpieceaccuracyandsurfaceroughnessonthelessdemandingposition,butalsocanbeusedasthefinalprocessing.③finishing:cuttingwithafinewaytoachievehighermachiningsurfaceaccuracyandsurfacequality,suchasfinecars,fineplanning,precisionhinges,grindingandsoon.Generalisthefinalfinishingprocess.④Finishingprocess:afterthefinish,theaimistoobtainasmallersurfaceroughnessandtoslightlyimprovetheaccuracy.Finishingprocessingallowanceissmall,suchashoning,grinding,ultra-precisiongrindingandsuperfinishingandsoon.⑤Modificationprocess:theaimistoreducethesurfaceroughness,toimprovethecorrosion,dustpropertiesandimproveappearance,butdoesnotrequirehigherprecision,suchaspolishing,sanding,etc.⑥ultra-precisionmachining:aerospace,lasers,electronics,nuclearenergyandothercutting-edgetechnologiesthatneedsomespecialprecisionparts,highaccuracyoverIT4,surfaceroughnesslessthanRamicrons.Thisneedtotakespecialmeasurestoultra-precisionmachining,suchasturningmirror,mirrorgrinding,chemicalmechanicalpolishingofsoftabrasive.Distinguishedbymethodofsurfacemachining,theworkpieceistorelyonthemachinedsurfaceforcuttingtoolandtheworkpiecetoobtaintherelativemotion.Bysurfacemethods,cuttingcanbedividedintothreecategories.①tiptrajectorymethod:relyingonthetiprelativetothetrajectoryofthesurfacetoobtaintherequiredworkpiecesurfacegeometry,suchascylindricalturning,planningsurface,cylindricalgrinding,withtheformingsurface,suchasbyturningmode.Thetrajectorydependsonthetooltipprovidedbythecuttingtoolandworkpiecerelativemotion.②formingtoolmethod:shortformingmethod,withthefinalworkpiecesurfaceprofilethatmatchestheshapeformingcutterorgrindingwheel,suchasprocessingashapedsurface.Atthistimeformingpartofthemachinemovementwasreplacedbythebladegeometry,suchastheshapeofturning,millingandforminggrindingformingandsoon.Themoredifficultthemanufactureofformingcutter,machine-clamp-workpiece-toolformedbytheprocesssystemcanwithstandthecuttingforceislimited,formingmethodisgenerallyusedforprocessingshortshapedsurface.③generatingmethod:alsoknownasrotarycuttingmethod,cuttingtoolandworkpieceduringprocessingasarelativelydevelopedintoacampaigntool(orwheel)andtheworkpieceinstantaneouscenterlineofpurerollinginteractionbetweenthetwomaintainacertainratiobetweenIsobtainedbyprocessingthesurfaceofthebladeinthismovementintheenvelope.Gearmachininghobbling,gearshaping,shaving,honing,andgrindingteeth(notincludingformgrindingteeth),etc.aregeneratingmethodprocessing.PLCEarlycalledtheprogrammablelogiccontrollerPLC(ProgrammableLogicController,PLC),whichismainlyusedtoreplacethelogiccontrolrelays.Withthetechnology,whichusesmicro-computertechnology,industrialcontroldevicefunctionhasbeengreatlyexceededthescopeoflogiccontrol,therefore,suchadevicetodaycalledprogrammablelogiccontroller,referredtoasthePC.However,inordertoavoidpersonalcomputer(PersonalComputer)intheshortconfusion,itwillbereferredtoasprogrammablelogiccontrollerPLC,plcsince1966,the.DigitalEquipmentCorporation(DEC)developedthere,thecurrentUnitedStates,Japan,Germany,PLCGoodqualityandpowerful.ThebasicstructureofProgrammableLogicControllerA.PowerPLC'spowerinthewholesystemplaysaveryimportantrole.Ifyoudonothaveagood,reliablepowersystemisnotworking,sothePLCmanufacturersdesignandmanufactureofpowerveryseriously.GeneralACvoltagefluctuationsof+10%(+15%)range,youcannottakeothermeasurestoPLCtoconnectdirectlytotheACcessingunit(CPU)Centralprocessingunit(CPU)isthecentralPLCcontrol.ItisgivenbythefunctionofPLCsystemprogramfromtheprogrammerreceivesandstorestheuserprogramanddatatype;checkthepowersupply,memory,I/Oandtimeralertstatus,andtodiagnosesyntaxerrorsintheuserprogram.WhenthePLCintorun-time,firstitscansthescenetoreceivethestatusofvariousinputdevicesanddata,respectively,intoI/Oimagearea,andthenonebyonefromtheuserprogramreadstheuserprogrammemory,afterashellandpressProvisionsoftheDirectivetheresultoflogicorarithmeticoperationsintotheI/Oimageareaordataregister.Andtheentireuserprogramisfinished,andfinallyI/Oimageareaofthestateortheoutputoftheoutputregisterdatatotheappropriateoutputdevice,andsoontorununtilstopped.TofurtherimprovethereliabilityofPLC,PLCisalsolargeinrecentyearsconstitutesaredundantdual-CPUsystem,orbythreevotingsystemsCPU.Thus,evenifaCPUfails,thewholesystemcanstillworkproperly.Storagesystemsoftwareofmemorycalledsystemprogrammemory.Storageapplicationsoftwareofmemorycalledtheuserprogrammemory.andoutputinterfacecircuittheliveinputinterfacecircuitbytheopticalcouplingcircuitandthecomputerinputinterfacecircuit,theroleofPLCandfieldcontrolofaninterfaceforinputchannels.Fieldoutputinterfacecircuitbytheoutputdataregisters,interruptrequeststrobecircuitandintegratedcircuit,theroleofPLCoutputinterfacecircuitthroughtheon-siteimplementationofpartsoftheoutputtothefieldcorrespondingcontrolsignal.moduleSuchascounting,positioningmodules.moduleSuchasEthernet,RS485,Prefabs-DPcommunicationmodule.數控系統數控系統是數字控制系統簡稱，英文名稱為NumericalControlSystem,初期是由硬件電路組成的稱為硬件數控（HardNC）,1970年代以后，硬件電路元件慢慢由專用的運算機代替稱為運算機數控系統。運算機數控（Computerizednumericalcontrol,簡稱CNC）系統是用運算機控制加工功能，實現數值控制的系統。CNC系統按照運算機存儲器中存儲的控制程序，執行部份或全數數值控制功能，并配有接口電路和伺服驅動裝置的專用運算機系統。CNC系統由數控程序、輸入裝置、輸出裝置、運算機數控裝置（CNC裝置）、可編程邏輯控制器（PLC）、主軸驅動裝置和進給（伺服）驅動裝置（包括檢測裝置）等組成。CNC系統的核心是CNC裝置。由于利用了運算機，系統具有了軟件功能，又用PLC代替了傳統的機床電器邏輯控制裝置，使系統更小巧，其靈活性、通用性、靠得住性更好，易于實現復雜的數控功能，利用、保護也方便，并具有與上位機連接及進行遠程通信的功能。目前世界上的數控系統種類繁多，形式各異，組成結構上都有各自的特點。這些結構特點來源于系統初始設計的大體要求和工程設計的思路。例如對點位控制系統和持續軌跡控制系統就有截然不同的要求。對于T系統和M系統，一樣也有專門大的區別，前者適用于回轉體零件加工，后者適合于異形非回轉體的零件加工。對于不同的生產廠家來講，基于歷史進展因素和各自因地而異的復雜因素的影響，在設計思想上也可能各有所長。例如，美國Dynapath系統采用小板結構，便于板子改換和靈活扣合，而日本FANUC系統則趨向大板結構，使之有利于系統工作的靠得住性，促使系統的平均無端障率不斷提高。但是無論哪一種系統，它們的大體原理和組成是十分相似的。一般整個數控系統由三大部份組成，即控制系統，伺服系統和位置測量系統。控制系統按加工工件程序進行插補運算，發出控制指令到伺服驅動系統；伺服驅動系統將控制指令放大，由伺服電機驅動機械按要求運動；測量系統檢測機械的運動位置或速度，并反饋到控制系統，來修正控制指令。這三部份有機結合，組成完整的閉環控制的數控系統。控制系統主要由總線、CPU、電源、存貯器、操作面板和顯示屏、位控單元、可編程序控制器邏輯控制單元和數據輸入/輸出接口等組成。最新一代的數控系統還包括一個通信單元，它可完成CNC、PLC的內部數據通信和外部高次網絡的連接。伺服驅動系統主要包括伺服驅動裝置和電機。位置測量系統主如果采用長光柵或圓光柵的增量式位移編碼器。數控系統的硬件由數控裝置、輸入/輸出裝置、驅動裝置和機床電器邏輯控制裝置等組成，這四部份之間通過I/O接口互連。數控裝置是數控系統的核心，其軟件和硬件來控制各類數控功能的實現。數控裝置的硬件結構按CNC裝置中的印制電路板的插接方式能夠分為大板結構和功能模塊（小板）結構；按CNC裝置硬件的制造方式，能夠分為專用型結構和個人運算機式結構；按CNC裝置中微處置器的個數能夠分為單微處置器結構和多微處置器結構。（1）大板結構和功能模板結構1）大板結構大板結構CNC系統的CNC裝置由主電路板、位置控制板、PC板、圖形控制板、附加I/O板和電源單元等組成。主電路板是大印制電路版，其它電路板是小板，插在大印制電路板上的插槽內。這種結構類似于微型運算機的結構。2）功能模塊結構（2）單微處置器結構和多微處置器結構1）單微處置器結構在單微處置器結構中，只有一個微處置器，以集中控制、分時處置數控裝置的各個任務。2）多微處置器結構隨著數控系統功能的增加、數控機床的加工速度的提高，單微處置器數控系統已不能知足要求，因此，許多數控系統采用了多微處置器的結構。若在一個數控系統中有兩個或兩個以上的微處置器，每一個微處置器通過數據總線或通信方式進行連接，共享系統的公用存儲器與I/O接口，每一個微處置器分擔系統的一部份工作，這就是多微處置器系統。CNC軟件分為應用軟件和系統軟件。CNC系統軟件是為實現CNC系統各項功能所編制的專用軟件，也叫控制軟件，寄存在運算機EPROM內存中。各類CNC系統的功能設置和控制方案各不相同，它們的系統軟件在結構上和規模上不同專門大，可是一般都包括輸入數據處置程序、插補運算程序、速度控制程序、管理程序和診斷程序。(1)輸入數據處置程序它接收輸入的零件加工程序，將標準代碼表示的加工指令和數據進行譯碼、數據處置，并按規定的格式寄存。有的系統還要進行補償計算，或為插補運算和速度控制等進行估計算。通常，輸入數據處置程序包括輸入、譯碼和數據處置三項內容。(2)插補計算程序CNC系統按照工件加工程序中提供的數據，如曲線的種類、起點、終點等進行運算。按照運算結果，別離向各坐標軸發出進給脈沖。那個進程稱為插補運算。進給脈沖通過伺服系統驅動工作臺或刀具作相應的運動，完成程序規定的加工任務。CNC系統是一邊插補進行運算，一邊進行加工，是一種典型的實時控制方式，所以，插補運算的快慢直接影響機床的進給速度，因此應該盡可能地縮短運算時刻，這是編制插補運算程序的關鍵。(3)速度控制程序速度控制程序按照給定的速度值控制插補運算的頻率，以保預定的進給速度。在速度轉變較大時，需要進行自動加減速控制，以避免因速度突變而造成驅動系統失步。⑷管理程序管理程序負責對數據輸入、數據處置、插補運算等為加工進程服務的各類程序進行調度管理。管理程序還要對面板命令、時鐘信號、故障信號等引發的中斷進行處置。(5)診斷程序診斷程序的功能是在程序運行中及時發覺系統的故障，并指出故障的類型。也能夠在運行前或故障發生后，檢查系統各主要部件(CPU、存儲器、接口、開關、伺服系統等)的功能是不是正常，并指動身生故障的部位。切削加工任何切削加工都必需具有3個大體條件:切削工具、工件和切削運動。切削工具應有刃口，其材質必需比工件堅硬。不同的刀具結構和切削運動形式組成不同的切削方式。用刃形和刃數都固定的刀具進行切削的方式有車削、鉆削、鏜削、銃削、刨削、拉削和鋸切等；用刃形和刃數都不固定的磨具或磨料進行切削的方式有磨削、研磨、珩磨和拋光等。切削加工是機械制造中最主要的加工方式。雖然毛坯制造精度不斷提高，精鑄、精鍛、擠壓、粉末冶金等加工工藝應用日廣，但由于切削加工的適應范圍廣，且能達到很高的精度和很低的表面粗糙度