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附录附录1英文翻译DIMENSIONALCONTROLINTHEEARLYDAYSOFENGINEER,THEMATINGOFPARTSWASACHIEVEDBYMACHININGONEPARTASNEARLYASPOSSIBLETOTHEREQUIREDSIZE,MACHININGTHEMATINGPARTNEARLYTOSIZE,ANDTHENCOMPLETINGITSMACHINING,CONTINUALLYOFFERINGTHEOTHERPARTTOIT,UNTILTHEDESIREDRELATIONSHIPWASOBTAINEDIFITWASINCONVENIENTTOOFFERONEPARTTOTHEOTHERPARTDURINGMACHINING,THEFINALWORKWASDONEATTHEBENCHBYAFITTER,WHOSCRAPEDTHEMATINGPARTSUNTILTHEDESIREDFITWASOBTAINED,THEFITTERTHEREFOREBEINGA‘FITTER’INTHELITERALSENSEITISOBVIOUSTHATTHETWOPARTSWOULDHAVETOBEDONEALLOVERAGAININTHESEDAYS,WEEXPECTTOBEABLETOPURCHASEAREPLACEMENTFORABROKENPART,ANDFORITTOFUNCTIONCORRECTLYWITHOUTTHENEEDFORSCRAPINGANDOTHERFITTINGOPERATIONSWHENONEPARTCANBEUSED‘OFFTHESHELF’TOREPLACEANOTHEROFTHESAMEDIMENSIONANDMATERIALSPECIFICATION,THEPARTSARESAIDTOBETOBEINTERCHANGEABLEASYSTEMOFINTERCHANGEABILITYUSUALLYLOWERSTHEPRODUCTIONCOSTS,ASTHEREISNONEEDFORANEXPENSIVE‘FIDDLING’OPERATION,ANDITALSOBENEFITSTHECUSTOMERINTHEEVENTOFTHENEEDTOREPLACEWORNPARTSITALSO,HOWEVER,DEMANDSTHATTHEDIMENSIONOFMATINGPARTSBESPECIFIED,ANDTHATDIMENSIONALVARIATIONS,DUETOMACHINEANDOPERATORSHORTCOMINGS,BETAKENINTOACCOUNTSOMEFORMOFINSPECTIONMUSTBEINTRODUCEDTOENSURETHATTHEMANUFACTUREISCONTROLLED；THISISPARTICULARLYIMPORTANT,BECAUSEDIMENSIONALERRORSMAYNOTBEREVEALEDUNTILSOMETIMEHASELAPSED,ANDOFTENMANYMILESFROMTHEPLACEWHERETHEMACHININGWASDONE1TOLERANCEANDLIMITSOFSIZESINCEITISACCEPTEDTHATITISVIRTUALLYIMPOSSIBLETOMANUFACTUREAPARTWITHOUTERROR,ORINTHERAREEVENTOFAPARTBEINGWITHOUTERROR,TOBEABLETOPROCLAIMITTOBEPERFECTBECAUSETHEMEASURINGINSTRUMENTSARESUBJECTTOERRORS,ITISNECESSARYTOINDICATETHEMAXIMUMERRORSPERMITTEDTHEDRAUGHTSMANMUSTINDICATETHELARGESTANDSMALLESTSIZESTHATTHELIMITSOFSIZE,ANDTHEDIFFERENCEBETWEENTHEMISCALLEDTHETOLERANCE,THEACTUALTOLERANCEMUSTBEINCREASEDWITHSIZETHETOLERANCESHOULDBEASLARGEASPOSSIBLE,TOKEEPTHECOSTTOAMINIMUMTHEMETHODOFINDICATING,ONADRAWING,THEPERMITTEDTOLERANCEDEPENDSMAINLYUPONTHETYPEOFOPERATIONINVOLVED,BUTLOCALPREFERENCEMUSTALSOBETAKENINTOACCOUNTTHEFOLLOWINGEXAMPLESWILLILLUSTRATESOMEOFTHEMETHODSUSED,1UNILATERALLIMITSTHESEAREUSUALLYUSEDWHENTHEDISTANCEBETWEENTWOFACES,ORTHEDIAMETEROFAHOLEORSHAFTIDSPECIFIEDFOREXAMPLE,WHENADIAMETERISBEINGGROUND,THEMACHINISTWOULDPREFERTOAIMATTHELARGESTSIZEPERMITTED,SOTHAT,INTHEEVENTOFHISREACHINGADIAMETERTHATISJUSTALITTLELARGERTHANTHEMAXIMUMSIZEPERMITTED,HECANTAKEANOTHERCUT,KNOWINGTHATHECANUSEUPTHEWHOLEOFTHETOLERANCEBEFORETHEJOBISREJECTEDADRAUGHTSMANMIGHTDIMENSIONANOMINAL750012MMDIAMETERSHAFTASD75SIMILARLY,ANOMINAL75MMHOLEMIGHTDIMENSIONEDASD750012,THESAMEREASONINGAPPLIESASFORSHAFTS2BILATERALLIMITSTHESEAREUSUALLYAPPLIEDWHEN,FOREXAMPLE,THEPOSITIONOFAHOLEISSPECIFIEDTHEMACHINEOPERATORMAYPOSITIONHEHOLENEARERTHEDATUMORFURTHERFROMTHEDATUMTHANINTENDED,HEMUSTAIMBETWEENTHELIMITSOFPOSITION,SOTHATTHEMAXIMUMERRORCANBEMADEWITHOUTCAUSINGTHEPARTTOBEREJECTEDTHECENTERDISTANCEBETWEENTWOHOLESWOULDTHEREFOREBESPECIFIEDAS,FOREXAMPLE,100002MM2FITSARECONCERNEDWITHTHERELATIONSHIPBETWEENTWOPARTSCONSIDERASHAFTANDAHOLECOMBINATIONIFTHESHAFTISLARGERTHANTHEHOLE,THECONDITIONISSAIDTOBEOFINTERFERENCE；ANDIFSMALLERTHANTHEHOLE,THECONDITIONISSAIDTOBEOFCLEARANCETHEINTERFERENCEMAYBESUCHTHATTHETWOPARTSCANBEASSEMBLEDONLYBYSHRINKING,ORITMAYBEVERYSLIGHT,SOTHATTHEPARTSCANBEASSEMBLEDBYHANDOPERATEDPRESSSIMILARLY,THECLEARANCECANBESLIGHT,SOTHATTHESHAFTCANROTATEEASILYINTHEHOLE,ORBELARGE,SOTHATTHEREISAMPLECLEARANCEFORBOLTSTOPASSTHROUGHINORDERTHATTHEPRECISECONDITIONISENSURED,THELIMITSOFSIZEOFBOTHTHESHAFTANDTHEHOLEMUSTBESTIPULATED1CLASSESOFFITTHESEARECLASSIFIEDASFOLLOWSCLEARANCEFITWHENTHELIMITSOFSIZEOFBOTHTHEHOLEANDTHESHAFTARESUCHTHATTHESHAFTISALWAYSSMALLERTHANTHEHOLE,THEFITIDSAIDTOBEACLEARANCEFITINTERFERENCEFITWHENTHELIMITSOFSIZEOFBOTHTHEHOLEANDTHESHAFTARESUCHTHATTHESHAFTISALWAYSLARGERTHANTHEHOLE,THEFITIDSAIDTOBEAINTERFERENCEFITTRANSITIONFITWHENTHELIMITSOFSIZEOFBOTHTHEHOLEANDTHESHAFTARESUCHTHATTHECONDITIONMAYBECLEARANCEORINTERFERENCE,THEFITIDSAIDTOBEATRANSITIONFIT2HOLEBASEDSYSTEMANDSHAFTBASEDSYSTEMINORDERTOOBTAINARANGEOFDEGREESOFCLEARANCE,ANDDEGREESOFINTERFERENCE,ITISNECESSARYTOUSEAWIDEVARIATIONOFHOLESIZESANDSHAFTSIZESFOREXAMPLE,AMANUFACTURINGCOMPANYCOULDBEMAKINGANUMBEROFPARTS,ALLOFANOMINAL25MMDIAMETER,BUTWHICHAREALLSLIGHTLYDIFFERENTINACTUALLIMITSOFSIZE,TOSUITTHEACTUALFITREQUIREDOFEACHPAIROFPARTSTHISSITUATIONCOULDMEANTHATALARGENUMBEROFDRILLS,REAMERS,GAUGES,ETCWEREREQUIREDITISLOGICALTHAT,TOREDUCETHISNUMBER,ASTANDARDHOLECOULDBEUSEDFOREACHNOMINALSIZE,ANDTHEVARIATIONOFFITEOBTAINEDBYMAKINGTHEMATINGSHAFTSMALLERORLARGERTHANTHEHOLETHISISKNOWNASAHOLEBASEDSYSTEMALTERNATIVELY,ASTANDARDSHAFTCOULDBEUSEDFOREACHNOMINALSIZE,ANDTHEVARIATIONOFFITISOBTAINEDBYMAKINGTHEMATINGHOLELARGERORSMALLER,ASREQUIREDTHISISKNOWNASASHAFTBASEDSYSTEMAHOLEBASEDSYSTEMISUSUALLYPREFERRED,BECAUSEITSTANDARDIZES“FIXEDSIZE”EQUIPMENTSUCHASREAMERANDPLUGGAUGES；BUTASHAFTBASEDSYSTEMISUSUALLYALSOPROVIDED,BECAUSESOMETIMESITISMORECONVENIENTTOEMPLOYACOMMONSHAFTTOWHICHANUMBEROFCOMPONENTSISASSEMBLED,EACHWITHADIFFERENTFIT,ANDSOMETIMESITISCONVENIENTTOUSEBARSTOCKWITHOUTFURTHERMACHINING3SYSTEMSOFLIMITSANDFITSITISCONVENIENTTOESTABLISHASTANDARDIZEDSYSTEMOFLIMITSANDFITS,NOTONLYTOELIMINATETHENEEDFORTHEDRAUGHTSMANTODETERMINETHELIMITSEACHTIMEANASSEMBLYISDETAILED,BUTALSOTOSTANDARDIZETHETOOLSANDGAUGESREQUIREDASYSTEMOFLIMITSANDFITSSHOULDCATERFORAWIDERANGEOFNOMINALSIZESTOSATISFYTHEVARIOUSNEEDSOFINDUSTRY,ANDSHOULDCATERFORAWIDERANGEOFQUALITYOFWORKTHESYSTEMSHOULD,IFPOSSIBLE,BETABULATED,TOSAVETHEUSERTHETROUBLEOFHAVINGTOCALCULATETHELIMITSOFSIZETOSUITOFTHECLASSOFFIT,THEQUALITYOFTHEWORK,ANDTHESIZEOFTHEPART4BRITISHSTANDARD45001969,ISOLIMITSANDFITSTHISSTANDARDREPLACEBS4500ISESSENTIALLYAREVISIONOFBS1961TOBRINGTHEBRITISHSTANDARDINTOLINEWITHTHELATESTRECOMMENDATIONSOFTHEINTERNATIONALORGANIZATIONFORSTANDARDIZATIONISOTHESYSTEMREFERSTOHOLESANDSHAFTS,BUTTHESETERMSDONOTONLYAPPLYTOCYLINDRICALPARTSBUTCANEQUALLYWELLBEAPPLIEDTOTHESPACECONTAINEDBYORCONTAINING,TWOPARALLELFACESORTANGENTPLANESTHESYSTEMISTABULATED,ANDCOVERSSIZESUPTO3150MMTHENUMERICALCONTROL’SDEVELOPMENTTHEFIRSTELECTRONICCOMPUTERINTHEWORLDEMERGEDIN1946,THISINDICATESTHEMANKINDHASCREATEDTHETOOLTHATCANSTRENGTHENANDREPLACETHEMENTALLABOURPARTLYIT,ANDMANKINDTHOSETHATCREATETOSTRENGTHENTOOLOFMANUALLABORCOMPAREAMONGAGRICULTURE,INDUSTRIALSOCIETY,THEQUALITATIVELEAPHASARISEN,HASESTABLISHEDTHEFOUNDATIONTHATTHEMANKINDENTERSTHEINFORMATIONINTENSIVESOCIETY6YEARSLATER,NAMELYIN1952,THETECHNOLOGYOFTHECOMPUTERWASAPPLIEDTOTHELATHE,THEFIRSTNUMERICALCONTROLLATHEHASEMERGEDINUSAFROMTHENON,THETRADITIONALLATHEHADPRODUCEDTHECHANGEOFTHEQUALITYINNEARLYHALFACENTURY,THENUMERICALCONTROLSYSTEMWENTTHROUGHTWOSTAGESANDSIXGENERATIONSDEVELOPMENTTHENUMERICALCONTROLLATHEISREGARDEDASTHEINTEGRATEDTYPICALPRODUCTSOFELECTROMECHANICS,PLAYANENORMOUSROLEAMONGMECHANICALMANUFACTURINGINDUSTRY,SOLVESTRUCTURECOMPLICATED,ACCURATE,BATCHLITTLE,CHANGEABLEPROCESSINGPROBLEMOFPARTINTHEMODERNMACHINEBUILDINGWELL,ANDCANSTABILIZETHEPROCESSINGQUALITYOFTHEPRODUCTS,IMPROVEPRODUCTIONEFFICIENCYBYALARGEMARGINBUTSEENFROMSITUATIONWHICHENTERPRISESFACEATPRESENT,BECAUSETHENUMERICALCONTROLLATHEPRICEISRELATIVELYEXPENSIVE,AMBASSADORSENTERPRISESAREUNABLETODOWHATONEWANTSVERYMUCHTODOTORELATIVELYMAKETHEINVESTMENTONCEONLYOURCOUNTRYCANYETBEREGARDEDASAKINDOFBETTERGOODPLANTOTHENUMERICALCONTROLTRANSFORMATIONOFTHEORDINARYLATHEASTHELATHEBIGCOUNTRYTHISTEXTPROPOSESTOTHEDOMESTICENTERPRISESCURRENTSITUATIONATPRESENTTHEECONOMICNUMERICALCONTROLOFTHESIMPLEANDEASYTYPETRANSFORMSTHETHINKINGANDDESIGNMETHODFORTECHNICALSTAFFOFNUMERICALCONTROLSREFERENCENUMERICALCONTROLTRANSFORMATIONMEANTOORDINARYLATHESOMEPOSITIONMAKECERTAINTRANSFORMATIONGENERALLY,MATCHTHENUMERICALCONTROLDEVICE,THUSMAKETHELATHEHAVEWORKINGABILITYOFNUMERICALCONTROL,ITSPURPOSEISFORIMPROVINGMACHININGACCURACYOFTHEOLDEQUIPMENTANDPRODUCTIONEFFICIENCY,ADAPTTOMANYVARIETYANDPRODUCTION,SHORTRUNOFPART,CANMAKEINDUSTRIALGRADECANPROCESSTHEHIGHQUALITYPARTTOOTHANLOWWORKERATTHESAMETIME,REDUCEINVESTMENTOFTECHNOLOGICALTRANSFORMATIONOFTHEEQUIPMENT,ETCPRICEPERFORMANCEONALLTHESEFORIMPROVINGBEENFORLATHETHAN,NAMELYLASTMECHANICAL