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ID:50049623
大小:159.50 KB
页数:24页
时间:2020-03-08
《数控技术专业英语 教学课件 作者 黄义俊 电子教案统一模板(数控)Unit4.ppt》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、Unit4TheComponentsofCNCMachinesLesson7TheConstructionofCNCMachines4.1Lesson8TheComponentsofCNCMachines4.2ReadingMaterials7TheOperationPanelofCNCMachinesⅠ4.3ReadingMaterials8TheOperationPanelofCNCMachinesⅡ4.44.1Lesson7TheConstructionofCNCMachinesCNCmachine
2、toolsarecomplexassemblies.Ingeneral,CNCmachinetoolconsistsofthefollowingunits:1.Computer—Aswithallcomputers,theCNCmachinecomputerworksonabinaryprincipleusingonlytwocharacters1and0,forinformationprocessingprecisetimeimpulsesfromthecircuit.Therearetwostates
3、,astatewithvoltage,1,andastatewithoutvoltage,0.Seriesofonesandzeroesaretheonlystatesthatthecomputerdistinguishesacalledmachinelanguage,whichistheonlylanguagethecomputerunderstands.Whencreatingtheprogram,theprogrammerdoesnotcareaboutthemachinelanguage.Heor
4、shesimplyusesalistofcodesandkeysinthemeaningfulinformation.Specialbuilt-insoftwarecompilestheprogramintomachinelanguageandthemachinemovesthetoolbyitsservomotors.However,theprogrammabilityofthemachineisdependentonwhetherthereisacomputerinthemachine’scontro
5、l.2.Controlsystem—TherearetwotypesofcontrolsystemsonNC/CNCmachines:open-loopandclosed-loop.Thetypeofcontrolloopuseddeterminestheoverallaccuracyofthemachine.Theopen-loopcontrolsystemdoesnotprovidepositioningfeedbacktothecontrolunit.Theclosed-loopcontrolsys
6、temisveryaccurate.Ithasanautomaticcompensativefunctionforerror,sincethefeedbackdeviceindicatestheerrorandthecontrolmakesthenecessaryadjustmentstobringtheslidebacktotheposition.TheyapplyAC,DCorhydraulicservomotors.3.Drivemotors—Thedrivemotorscontrolthemach
7、ineslidemovementonNC/CNCequipment.Theyfallintofourbasictypes:Steppermotorsconvertadigitalpulsegeneratedbythemicrocomputerunit(MCU)intoasmallsteprotation.Steppermotorsareusedinopen-loopcontrolsystems,whileAC,DCorhydraulicservomotorsareusedinclosed-loopcon
8、trolsystems.Directcurrent(DC)servomotorsarevariablespeedmotorsthatrotateinresponsetotheappliedvoltage.Theyareusedtodrivealeadscrewandgearmechanism.DCservomotorsprovidehigher-torqueoutputthansteppermotors.Alternati
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