数控技术：Numerical Control Technology和数控机床编程及加工

《NCTechnology》

机电工程学院主讲：蒋廷彪

NumericalControlTechnology《NCTechnology》

Ch1introduction《NCTechnology》

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

WhatisNC&CNC?

NC:NumericalControl

数控(技术)CNC:ComputerNumericalControl

计算机数控(技术)NCmachinetool数控机床《NCTechnology》

PrincipleofNCmachinetool

Howtorealizemachining?relativemovement!WhatistheNCmachinetool?Theprogrammednumericalcommandsareusedtocontroltherelativemovementandactionsofmachinetool!《NCTechnology》

AnexampleN003G90G01X+325.9Y+279.346Z-429.7S1000T02F500M07第三程序段绝对坐标直线段加工终点坐标主轴转速2号刀具进给速度冷却液打开《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.从1974年开始采用微型电子计算机控制的系统(MicrocomputerNumericalControl----MNC)《NCTechnology》

CURRENTDEVOLOPMENT

OPENCNC《NCTechnology》

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AdvantagesandLimitationsofCNC《NCTechnology》

AdvantagesandLimitationsofCNC《NCTechnology》

请大家欣赏机床发展的历史回顾《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（直线）Circular（圆弧）Helical（螺旋线）Parabolic（抛物线）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（铣削）Turning（车外圆）Electricdischargemachining,orEDM（电火花）Punching（冲压）Formingandbending（成形与弯曲）Grinding（磨削）Flameandlasercutting（激光切割）Inspection（检测）Robotics

（机器人）《NCTechnology》

HomeworkNarratetheconceptofNC,CNC&NCmachine.WhatarethecomponentsofNCmachinetool?Whatisthepoint-to-pointcontrol,contouringcontrolNCmachine?Whatistheopen-loopcontrol,half-closed-loopcontrolandclosed-loopcontrolmachineandtheirdifference?数控机床编程及加工机械工程实验教学中心实验目的通过数控机床的加工程序编制，掌握编程的方法及技巧；将在计算机上用OpenSoftCNC软件模拟显示加工过程校验程序，然后在数控机床上对工件进行加工；结合机械加工工艺，实现最优化编程，提高加工质量和生产效率。机械工程实验教学中心数控编程的基本原理数控编程的目的；数控编程的内容；编程步骤。机械工程实验教学中心数控编程的基本原理所谓编程，就是把零件的图形尺寸、工艺过程、工艺参数、机床的运动以及刀具位移等内容，按照数控机床的编程格式和能识别的语言记录在程序单上的全过程。这样编制的程序还必须按规定把程序单制备成控制介质如程序纸带、磁带等，变成数控系统能读懂的信息，再送入数控机床，数控机床的CNC装置对程序经过处理之后，向机床各坐标的伺服系统发出指令信息，驱动机床完成相应的运动。机械工程实验教学中心数控编程的目的数控编程的基本原理①分析零件图纸，确定加工工艺过程；②计算走刀轨迹，得出刀位数据；③编写零件加工程序；④制作控制介质；⑤校对程序及首件试加工。机械工程实验教学中心数控编程的内容数控编程的基本原理机械工程实验教学中心数控编程的步骤零件图纸分析零件图纸制定工艺规程数学处理编写程序文件制作控制介质程序校验及试切数控机床OpenSoftCNC软件介绍OpenSoftCNC软件包括数控车床模拟仿真和数控铣床模拟仿真系统，由软件+标准硬件系统构成，不要求专用硬件或运动控制卡，所有数控功能和逻辑控制功能均由软件完成，操作界面由系统操作和机床控制两大部分组成。机械工程实验教学中心OpenSoftCNC软件介绍机械工程实验教学中心为例，软件提供下列指令：以数控车床模拟仿真系统（OpenSoftCNC01T）组别指令功能编程格式模态

1G00快速线性移动G00X(U)_Z(W)_√G01直线插补G01X(U)_Z(W)_√G02顺时针圆弧插补G02I_K_X(U)_Z(W)_√G03逆时针圆弧插补G03I_K_X(U)_Z(W)_√G32恒螺距公制螺纹插补G32X(U)_Z(W)_K_I_H√G33恒螺距英制螺纹插补G33X(U)_Z(W)_K_I_H√G27X轴返回程序零点G27

G28Z轴返回程序零点G28

G92定义绝对坐标系G92X_Z_√2G04延时G04E_

3M00暂停M00

M02程序结束M02

4M03主轴正转M03√M04主轴反转M04√M05主轴停M05√5M08开冷却液M08√M09关冷却液M09√