數(shù)控技術(shù)：Numerical Control Technology和數(shù)控機(jī)床編程及加工

《NCTechnology》

機(jī)電工程學(xué)院主講：蔣廷彪

NumericalControlTechnology《NCTechnology》

Ch1introduction《NCTechnology》

Outline?Terms&basicconceptsHistoryofNCandCNC?NCversusCNC?BasicelementsofaCNCmachine?AdvantagesandlimitationofCNC?ModeofNCcontrolsystem《NCTechnology》

WhatisNC&CNC?

NC:NumericalControl

數(shù)控(技術(shù))CNC:ComputerNumericalControl

計(jì)算機(jī)數(shù)控(技術(shù))NCmachinetool數(shù)控機(jī)床《NCTechnology》

PrincipleofNCmachinetool

Howtorealizemachining?relativemovement!WhatistheNCmachinetool?Theprogrammednumericalcommandsareusedtocontroltherelativemovementandactionsofmachinetool!《NCTechnology》

AnexampleN003G90G01X+325.9Y+279.346Z-429.7S1000T02F500M07第三程序段絕對(duì)坐標(biāo)直線段加工終點(diǎn)坐標(biāo)主軸轉(zhuǎn)速2號(hào)刀具進(jìn)給速度冷卻液打開(kāi)《NCTechnology》

Computernumericalcontrol(CNC)istheprocessofmanufacturingmachinedparts.Productioniscontrolledandallocatedbyacomputerizedcontroller.Thecontrollerusesmotorstodriveeachaxisofamachinetoolandactuallyregulatesthedirection,speed,andlengthoftimeeachmotorrotates.Aprogrammedpathisloadedintothemachine'scomputerbytheoperatorandthenexecuted.Theprogramconsistsofnumericpointdatainconjunctionwithspecializedmachinecontrolcommandsandfunctioncodes.PrincipleofNCmachinetool

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TheworkprocessofNC《NCTechnology》

BasiccomponentsofCNCmachinetool《NCTechnology》

TheevolutionofNCTheprincipleofNCmanufacturinghasbeenevolvingsincetheIndustrialRevolution.NotuntilWorldWarIIdidindustrialistsrealizethattheycouldn'tmeetbothquantityandqualityrequirementsatthesametime.《NCTechnology》ENIACDuringWorldWarIItheUnitedStatesArmyBallisticResearchLabandtheUniversityofPennsylvaniacollaboratedondevelopmentofENIAC,theworld'sfirstdigitalcomputer.

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TheevolutionofNC

ToensurethatallU.S.militaryairplanesweremanufacturedidentically,theUnitedStatesAirForceinvitedseveralcompaniestodevelopandmanufacturenumericalcontrolsystemsthatcouldhandlethevolumeandrepeatability.ThefirstcontractwasawardedtotheParsonsCorporationofMichigan,whichthensubcontracteddevelopmentofaservosystemforthemachinetooltotheServomechanismLaboratoryatMIT《NCTechnology》

TheServoMechanismlaboratoryatMIT《NCTechnology》

TheevolutionofNCThespecificgoalsofdevelopingNC:IncreaseproductionImprovethequalityandaccuracyofmanufacturedpartsStabilizemanufacturingcosts

Manufactureandassemblecomplexpartsquickly《NCTechnology》

ThefirstNCmachineproducing

identicalparts《NCTechnology》TheevolutionofNCBy1960,NCwaswidelyacceptedandreadilyavailable.ThemajorityofthesefirstgenerationNCmachinetoolsrequiredcodedpapertapetorun.TheengineerswouldgenerateNCcodeontheircomputers,thenencodelongstripsofpapertapebypunchingholepatternsinthem.Later,theuseof“man-readable”solvedthisproblem《NCTechnology》

AnearlyNCpapertapereader《NCTechnology》

CNCDirectnumericalcontrolanddistributednumericalcontrol(DNC)describecommunicationstoamachinetoolfromaremotecomputer.《NCTechnology》

APTFrom1955to1960,MITalsodevelopedacomputer-assistedprogrammingsystemcalledautomaticallyprogrammedtools(APT).Thisprogramminglanguagewasdevelopedtoeasethetaskofcomplicatedthree-axisprogramming,mainlyintheaerospaceindustry.APTusesEnglish-likewordstodescribethegeometryandthetoolmotionsonapartprogram.《NCTechnology》

MICROCOMPUTERTECHNOLOGYThemoderncomputerisanelectronicmachinethatperformsmathematicalorlogicalcalculationsinaccordancewithapredeterminedsetofinstructions.從1974年開(kāi)始采用微型電子計(jì)算機(jī)控制的系統(tǒng)(MicrocomputerNumericalControl----MNC)《NCTechnology》

CURRENTDEVOLOPMENT

OPENCNC《NCTechnology》

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AdvantagesandLimitationsofCNC《NCTechnology》

AdvantagesandLimitationsofCNC《NCTechnology》

請(qǐng)大家欣賞機(jī)床發(fā)展的歷史回顧《NCTechnology》

NCSYSTEMCLASSIFICATIONBasedonmodeofcontrolBasedontypesofservo-drivesystemBasedonapplication……《NCTechnology》

ModeofNCcontrolSystemPointtopointPoint-to-pointsystem,alsocalledPositingcontrolsystem,movestheworktabletoaprogrammedlocationwithoutregardforthepathtakentogettothelocation.contouringcontrolsystemThecontouringfacilityenablesanNCmachinetofollowanypathatanyprescribedfeed-rate.

Thecontouringcontrolsystem,alsocalledcontinuouspathcontrolsystem,managesthesimultaneousmotionofthecuttingtoolintwo,three,four,orfiveaxesbyinterpolatingtheproperpathbetweenprescribedpoints.《NCTechnology》

Pointtopoint1:Axialpath《NCTechnology》

Pointtopoint2:45degreeslinepath3:Linearpath《NCTechnology》

CircularInterpolationTheoretically,Capableofcreatingcurveandcircle,usingincrementofsmalllineorpolygon.《NCTechnology》

Exampleofcontinuouspath《NCTechnology》

CNCInterpolationInterpolator

Hardwaredevice(NCsystem)

Softwareprogram(CNCsystem)Functions:Computeindividualaxisvelocitiestodrivetoolalongprogrammedpathatgivenfeed-rate.Generateintermediatecoordinatepositionsalongtheprogrampath.《NCTechnology》

TypesofInterpolation5typesofinterpolation:Linear（直線）Circular（圓?。〩elical（螺旋線）Parabolic（拋物線）Cubic(三次)《NCTechnology》

TypesofNCServo-DriveSystemsOpen-loopservo-driveHalf-closed-loopservo-driveclosed-loopservo-drive《NCTechnology》

Open-loopservo-drive《NCTechnology》

Open-loopservo-driveSimplestandleastcostformofservo-driveThesystemlacksfeedback,thatis,oncetheinputsignalissent,thereisnosensingdevicetoconfirmtheactionofthecontrolsignal.Theservomotorisusuallysteppingmotorsteppingmotoroutputshaftrotatesindirectproportiontopulsesreceived.

Highaccuracy,easyimplementationandcompatiblewithdigitalsignalslowtorque,limitedspeedandriskofmissedpulseunderload《NCTechnology》

ApplicationareaTheactionsperformedbythecontrolsystemaresimpleTheactuatingfunctionisveryreliableAnyreactionforcesopposingtheactuationaresmallenoughtohavenoeffectontheactuation.UsedintheeconomicNCmachine!《NCTechnology》

Half-closed-loopservo-drive《NCTechnology》

Half-closed-loopservo-driveIndirectfeedbackmonitorstheoutputofservomotor.PopularwithNCsystemThehalf-closed-loopsystemcomparesthecommandpositionsignalwiththedrivesignaloftheservomotor.Convenienttoadjust;goodstability.Unabletosensebacklashorleadscrewwindupduetovaryingloads.《NCTechnology》

closed-loopservo-drive《NCTechnology》

closed-loopservo-driveIndirectfeedbackmonitorstheoutputofservomotor.Feedbacksensordirectlymeasuresthepositionofworktable.Theoreticalpreferredsystem&moreaccurateHighercost,unstableConventionalvariable-speedACorDCmotors,calledservos.《NCTechnology》

CNCapplicationMilling（銑削）Turning（車外圓）Electricdischargemachining,orEDM（電火花）Punching（沖壓）Formingandbending（成形與彎曲）Grinding（磨削）Flameandlasercutting（激光切割）Inspection（檢測(cè)）Robotics

（機(jī)器人）《NCTechnology》

HomeworkNarratetheconceptofNC,CNC&NCmachine.WhatarethecomponentsofNCmachinetool?Whatisthepoint-to-pointcontrol,contouringcontrolNCmachine?Whatistheopen-loopcontrol,half-closed-loopcontrolandclosed-loopcontrolmachineandtheirdifference?數(shù)控機(jī)床編程及加工機(jī)械工程實(shí)驗(yàn)教學(xué)中心實(shí)驗(yàn)?zāi)康耐ㄟ^(guò)數(shù)控機(jī)床的加工程序編制，掌握編程的方法及技巧；將在計(jì)算機(jī)上用OpenSoftCNC軟件模擬顯示加工過(guò)程校驗(yàn)程序，然后在數(shù)控機(jī)床上對(duì)工件進(jìn)行加工；結(jié)合機(jī)械加工工藝，實(shí)現(xiàn)最優(yōu)化編程，提高加工質(zhì)量和生產(chǎn)效率。機(jī)械工程實(shí)驗(yàn)教學(xué)中心數(shù)控編程的基本原理數(shù)控編程的目的；數(shù)控編程的內(nèi)容；編程步驟。機(jī)械工程實(shí)驗(yàn)教學(xué)中心數(shù)控編程的基本原理所謂編程，就是把零件的圖形尺寸、工藝過(guò)程、工藝參數(shù)、機(jī)床的運(yùn)動(dòng)以及刀具位移等內(nèi)容，按照數(shù)控機(jī)床的編程格式和能識(shí)別的語(yǔ)言記錄在程序單上的全過(guò)程。這樣編制的程序還必須按規(guī)定把程序單制備成控制介質(zhì)如程序紙帶、磁帶等，變成數(shù)控系統(tǒng)能讀懂的信息，再送入數(shù)控機(jī)床，數(shù)控機(jī)床的CNC裝置對(duì)程序經(jīng)過(guò)處理之后，向機(jī)床各坐標(biāo)的伺服系統(tǒng)發(fā)出指令信息，驅(qū)動(dòng)機(jī)床完成相應(yīng)的運(yùn)動(dòng)。機(jī)械工程實(shí)驗(yàn)教學(xué)中心數(shù)控編程的目的數(shù)控編程的基本原理①分析零件圖紙，確定加工工藝過(guò)程；②計(jì)算走刀軌跡，得出刀位數(shù)據(jù)；③編寫零件加工程序；④制作控制介質(zhì)；⑤校對(duì)程序及首件試加工。機(jī)械工程實(shí)驗(yàn)教學(xué)中心數(shù)控編程的內(nèi)容數(shù)控編程的基本原理機(jī)械工程實(shí)驗(yàn)教學(xué)中心數(shù)控編程的步驟零件圖紙分析零件圖紙制定工藝規(guī)程數(shù)學(xué)處理編寫程序文件制作控制介質(zhì)程序校驗(yàn)及試切數(shù)控機(jī)床OpenSoftCNC軟件介紹OpenSoftCNC軟件包括數(shù)控車床模擬仿真和數(shù)控銑床模擬仿真系統(tǒng)，由軟件+標(biāo)準(zhǔn)硬件系統(tǒng)構(gòu)成，不要求專用硬件或運(yùn)動(dòng)控制卡，所有數(shù)控功能和邏輯控制功能均由軟件完成，操作界面由系統(tǒng)操作和機(jī)床控制兩大部分組成。機(jī)械工程實(shí)驗(yàn)教學(xué)中心OpenSoftCNC軟件介紹機(jī)械工程實(shí)驗(yàn)教學(xué)中心為例，軟件提供下列指令：以數(shù)控車床模擬仿真系統(tǒng)（OpenSoftCNC01T）組別指令功能編程格式模態(tài)

1G00快速線性移動(dòng)G00X(U)_Z(W)_√G01直線插補(bǔ)G01X(U)_Z(W)_√G02順時(shí)針圓弧插補(bǔ)G02I_K_X(U)_Z(W)_√G03逆時(shí)針圓弧插補(bǔ)G03I_K_X(U)_Z(W)_√G32恒螺距公制螺紋插補(bǔ)G32X(U)_Z(W)_K_I_H√G33恒螺距英制螺紋插補(bǔ)G33X(U)_Z(W)_K_I_H√G27X軸返回程序零點(diǎn)G27

G28Z軸返回程序零點(diǎn)G28

G92定義絕對(duì)坐標(biāo)系G92X_Z_√2G04延時(shí)G04E_

3M00暫停M00

M02程序結(jié)束M02

4M03主軸正轉(zhuǎn)M03√M04主軸反轉(zhuǎn)M04√M05主軸停M05√5M08開(kāi)冷卻液M08√M09關(guān)冷卻液M09√