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编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第PAGE10页共NUMPAGES10页第PAGE\*MERGEFORMAT10页共NUMPAGES\*MERGEFORMAT10页NumericalControlOneofthemostfundamentalconceptsintheareaofadvancedmanufacturingtechnologiesisnumericalcontrol(NC).PriortotheadventofNC,allmachinetoolsweremanualoperatedandcontrolled.Amongthemanylimitationsassociatedwithmanualcontrolmachinetools,perhapsnoneismoreprominentthanthelimitationofoperatorskills.Withmanualcontrol,thequalityoftheproductisdirectlyrelatedtoandlimitedtotheskillsoftheoperator.Numericalcontrolrepresentsthefirstmajorstepawayfromhumancontrolofmachinetools.Numericalcontrolmeansthecontrolofmachinetoolsandothermanufacturingsystemsthoughtheuseofprerecorded,writtensymbolicinstructions.Ratherthanoperatingamachinetool,anNCtechnicianwritesaprogramthatissuesoperationalinstructionstothemachinetool,Foramachinetooltobenumericallycontrolled,itmustbeinterfacedwithadeviceforacceptinganddecodingthep2ogrammedinstructions,knownasareader.Numericalcontrolwasdevelopedtoovercomethelimitationofhumanoperator,andithasdoneso.Numericalcontrolmachinesaremoreaccuratethanmanuallyoperatedmachines,theycanproducepartsmoreuniformly,theyarefaster,andthelong-runtoolingcostsarelower.ThedevelopmentofNCledtothedevelopmentofseveralotherinnovationsinmanufacturingtechnology:Electricaldischargemachining.Lasercutting.Electronbeamwelding.Numericalcontrolhasalsomademachinetoolsmoreversatilethantheirmanuallyoperatedpredecessors.AnNCmachinetoolcanautomaticallyproduceawidevarietyofpar4s,eachinvolvinganassortmentofundertaketheproductionofproductsthatwouldnothavebeenfeasiblefromaneconomicperspectiveusingmanuallycontrolledmachinetoolsandprocesses.Likesomanyadvancedtechnologies,NCwasborninthelaboratoriesoftheMassachusettsInstituteofTechnology.TheconceptofNCwasdevelopedintheearly1950swithfundingprovidedbytheU.SAirForce.Initsearlieststages,NCmachineswereabletomakestraightcutsefficientlyandeffectively.However,curvedpathswereaproblembecausethemachinetoolhadtobeprogrammedtoundertakea
