




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
UnitOneDialogueTextSupplementaryReadingDialogueTopicalIntroduction:TomandMaryhavenowjustfinishedaclassgivenbyProfessorSmithontheworkingsofthemachinetools.Yet,theystillhavesomequestions,andso,theywalkovertoProf.Smith.
下一页返回DialogueTom:(toProf.Smith)Excuseme,sir,I’mTom,oneofyourstudentsinthisclass.CouldIaskyousomequestions?Smith:(toTom)Whynot?Comeon,then
Tom:Whydowenamethesemachinesnumericalcontrolmachines?
Smith:Agoodquestion,boy.Youknow,uh-hm….,NC,ornumericalcontrol,actuallyreferstothecontrolofamachinetooloranyotherprocessingmachinesbyusingaseriesofmathematicalinformation,ornumericaldata.Itmeanstheworkofmachinesiscontrolledbyanumericalcontrolprogram.
下一页上一页返回DialogueMary:Oh,Prof.Smith,theideaisniceenough.Butwhatistheadvantageofnumericalcontrolmachiningoverthehandcontrol?Isn’tourhandmoresensibleorreliablethantheprogrammeddata?
Smith:Insomeways,yes.Agoodexampleissomefineworks,likeajadebox,butthequalitiesofhand-madeproductsmaynotbeconsistentorstable.Whatismoreimportant,NChasprovedtobemuchmoreadvantageousinoveralloperation.Mary:Butwhatdoyoumeanbyoveralloperation?下一页上一页返回DialogueSmith:Uh-huh,byitwemeanthegeneralindustrialproductionpractice.Forexample,NCshouldbeadoptedwheneverthereissimilarrawmaterialandworkpartsareproducedinvarioussizesandcomplexshapes.ThoseproductionshopsthatmayhavefrequentchangeoverswillsurelybenefitfromNCprograms.
Tom:Thankyou,Prof.Smith,butIhaveanotherquestion.HowcanweuseNCtogetmoresatisfactoryresultsintherealproduction?
下一页上一页返回DialogueSmith:It’sbettertouseNCtoolstogetherwithothertechnicaladvances,suchasprogrammedoptimizationofcuttingspeedsandfeeds,workpositioning,toolselection,andchipdisposal.Tom&Mary:ThankyouProf.Smith,NCsoundsreallypromisingfromwhatwesay.
上一页返回TextTheHistoryofCNCandNCDevelopment
下一页返回Text
NumericalControl(NC)isanymachiningprocessinwhichtheoperationsareexecutedautomaticallyinsequencesasspecifiedbytheprogramthatcontainstheinformationforthetoolmovements.TheNCconceptwasproposedinthelate1940sbyJohnParsonsofTraverseCity,Michigan.Parsonsrecommendedamethodofautomaticmachinecontrolthatwouldguideamillingcuttertoproducea“thru-axiscurve”inordertogeneratesmoothprofilesonworkpieces.
In1949,TheU.S.AirForceawardedParsonsacontracttodevelopanewtypeofmachinetoolthatwouldbeabletospeedupproductionmethods.
下一页上一页返回TextParsonscommissionedtheMassachusettsInstituteofTechnology(M.I.T)todevelopapracticalimplementationofhisconcept1.ScientistsandengineersatM.I.Tbuiltacontrolsystemforatwo-axismillingmachinethatusedaperforatedpapertapeastheinputmedia.Inashortperiodoftime,allmajormachinetoolmanufacturerswereproducingsomemachineswithNC,butitwasnotuntilthelate1970sthatcomputer-basedNCbecamewidelyused.NCmaturedasanautomationtechnologywheninexpensiveandpowerfulmicroprocessorsreplacedhard-wirelogic-makingcomputer-basedNCsystems.
下一页上一页返回Text下一页上一页返回TextWhenNumericalControlisperformedundercomputersupervision,itiscalledComputerNumericalControl(CNC).ComputersarethecontrolunitsofCNCmachines,theyarebuiltinorlinkedtothemachinesviacommunicationschannels.Whenaprogrammerinputsomeinformationintheprogrambytapeandsoon,thecomputercalculatesallnecessarydatatogetthejobdone.
OnthefirstNumericallyControlled(NC)machineswerecontrolledbytape,andbecauseofthat,theNCsystemswereknownastape-controlledmachines2.下一页上一页返回TextTheywereabletocontrolasingleoperationenteredintothemachinebypunchedormagnetictape.Therewasnopossibilityofeditingtheprogramonthemachine.Tochangetheprogram,anewtapehadtobemade.
Today’ssystemshavecomputerstocontroldata;theyarecalledComputerNumericallyControlled(CNC)machines.ForbothNCandCNCsystems,workprinciplesarethesame.Onlythewayinwhichtheexecutioniscontrolledisdifferent.Normally,newsystemsarefaster,morepowerful,andmoreversatile3.
上一页返回Notes
1.ParsonscommissionedtheMITtodevelopapracticalimplementationofhisconcept.帕森委托麻省理工学院开发他设想中的实际机器。todevelopa…作目的状语。
返回Notes2.Onthefirstnumericallycontrolled(NC)machines,numericaldatawascontrolledbytapeandbecauseofthat,theNCsystemwereknownastape-controlledmachine.that指代上一句onthefirstNumericallycontrolled(NC)machines,numericaldatawascontrolledbytape,可译为:在最初的NC机床上,其数据由磁带提供及控制,因此这种数控系统被称为磁盘控制机。
返回Notes3.Normally,newsystemsarefaster,morepowerful,andmoreversatile.normally,-ly结尾的副词单独作状语放于句首时,通常作评注状语。本句可译为:“一般说来,这种新系统加工速度更快,功率更大,功能更强。
返回SupplementaryReadingTheApplicationsofNC/CNC
Sinceitsintroduction,NCtechnologyhasfoundmanyapplications,includinglathesandturningcenters,millingmachinesandmachiningcenters,punches,electricaldischargemachines(EDM),flamecutters,grinders,andtestingandinspectionequipment.ThemostcomplexCNCmachinetoolsaretheturningcenter,showninFig.1-1(Amodemturningcenterwithaten-stationturretthatacceptsquick-changetools.
EachtoolcanbepositionedinSecondswiththepressofabutton).下一页返回Fig.1-1返回Fig.1-1Amodernturningcenterwithaten–stationturretthatacceptsquick-changetools
SupplementaryReadingAndthemachiningcentershowninFig.1-2(Verticalmachiningcenter,thetoolmagazineisontheleftofthemachine.Thecontrolpanelontherightcanbeswiveledbytheoperator)andFig.1-3(Horizontalmachiningcenter,equippedwithanautomatictoolchanger.Toolmagazinescanstore200cuttingtools).
下一页上一页返回Fig.1-2返回Fig.1-2Avertical-spindlemachinecenter
Fig.1-3返回Fig.1-3Ahorizontal-spindlemachinecenter
SupplementaryReadingWhenpreparingaprogramforaparticularoperation,theprogrammermustselectallcuttingdatausingrecommendationsforconventionalmachining.Thisincludesproperselectionofcuttingspeeds,federate,toolsandtoolgeometry,andsoon.Whentheprogrammerhaschosenallofthenecessaryinformationproperly,theoperatorloadstheprogramintothemachineandpressesabuttontostartthecuttingcycle.TheCNCmachinemovesautomaticallyfromonemachiningoperationtoano
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。
最新文档
- 江西水利职业学院《物流工程与设施规划》2023-2024学年第一学期期末试卷
- 山东省乐陵市第一中学2024-2025学年七年级数学第一学期期末经典模拟试题含解析
- 烟师大地球科学基础教案13第四纪地质
- 脑梗塞合并出血护理查房
- 幼儿园大班班务工作总结计划
- 肾内科护理课件
- 人教版九年级数学学习兴趣激发计划
- 本月心理健康教育工作
- 寒假辅导班.实践报告范文
- 五年级第二学期班主任培训提升计划
- 关于成立薪酬绩效管理委员会的通知1
- 2025年中国华融资产管理股份有限公司招聘笔试参考题库含答案解析
- 职场中的办公室行为礼仪
- 研学战略合作协议书范本
- 《poct院内培训》课件
- 《翻译批评与赏析》课程教学大纲
- 2025年月度工作日历含农历节假日电子表格版
- T-DACS 010-2023 奶牛养殖场生物安全管理规范
- 2025年保安员资格证培训题库及答案
- 诺如病毒感染的临床护理
- 完整版项目实施保密方案
评论
0/150
提交评论