CNCMachining Handbook
AbouttheAuthor AlanOverbyreceivedaB.S.inElectricalEngineeringfromArizonaStateUniversity. HehasalwayshadahobbyistinterestinCNCtechnology,andhasowned,pro-grammed,andoperatedseveralCNCroutersandengravingmachinesonaprofes-sionallevelwithinthesignageindustry.Mr.Overbywasco-ownerofCustomCNC, Inc.,acompanythatprovidednewandreplacementcontrollersystemstobothindi-vidualsandoriginalequipmentmanufacturers.
CNCMachining Handbook Building,Programming, andImplementation AlanOverby Mc Graw Hill NewYorkChicagoSanFrancisco Lisbon-LondonMadridMexicoCity MilanNewDelhiSanJuan SeoulSingaporeSydneyToronto
Cataloging-in-PublicationDataisonfilewiththeLibraryofCongress. McGraw-Hillbooksareavailableatspecialquantitydiscountstouseaspremiumsandsalespro-motions,orforuseincorporatetrainingprograms.Tocontactarepresentativepleasee-mailusat bulksales@mcgraw-hill.com. CNCMachiningHandbook Copyright©2011byTheMcGraw-HillCompanies,Inc.Allrightsreserved.PrintedintheUnited StatesofAmerica.ExceptaspermittedundertheUnitedStatesCopyrightActof1976,nopartofthis publicationmaybereproducedordistributedinanyformorbyanymeans,orstoredinadatabase orretrievalsystem,withoutthepriorwrittenpermissionofthepublisher. 1234567890QFR/QFR19876543210 ISBN978-0-07-162301-8 MHID0-07-162301-9 Thepageswithinthisbookwereprintedonacid-freepaper. SponsoringEditor JudyBass AcquisitionsCoordinator MichaelMulcahy EditorialSupervisor DavidE.Fogarty ProjectManager BaljinderKaur,Aptara,Inc. CopyEditor SheilaJohnston Proofreader DevDuttSharma Indexer Aptara,Inc. ProductionSupervisor PamelaA.Pelton Composition Aptara,Inc. ArtDirector,Cover JeffWeeks InformationcontainedinthisworkhasbeenobtainedbyTheMcGraw-HillCompanies,Inc.("McGraw-Hill")fromsources believedtobereliable.However,neitherMcGraw-Hillnoritsauthorsguaranteetheaccuracyorcompletenessofanvinformation publishedherein,andneitherMcGraw-Hillnoritsauthorsshallberesponsibleforanyerrors,omissions,ordamagesarising outofuseofthisinformation.ThisworkispublishedwiththeunderstandingthatMcGraw-Hillanditsauthorsaresupplying informationbutarenotattemptingtorenderengineeringorotherprofessionalservices.Ifsuchservicesarerequired,the assistanceofanappropriateprofessionalshouldbesought.
Contents Prefaceix PartIThePhysicalArchitecture 1CNCMachines3 CommonCNCApplications5 2GuideSystems23 RoundRail26 ProfileRail27 V-StyleRoller29 HybridRollerGuides32 3TransmissionSystems33 ScrewandNut35 LeadScrewandNut38 BallScrews41 RotatingNut42 RackandPinion42 Reducers46 TimingBeltandPulleys47 ConstructingaPulley-ReductionUnit49 4Motors55 StepperMotors57 ServoMotors61 StepperversusServo:ProsandCons63 Encoders64 PartIITheCNCController 5ControllerHardware69 Enclosure71 BreakoutBoard72 Drives75 PowerSupply76 AdjunctDevicesforControllerHardware78 Pendant79 Wiring83 V
viContents 6ControlSoftware85 Mach3ControlSoftware87 EnhancedMachineController,Version2(EMC2)88 AForewordonComputerOperatingSystemsandApplications89 G-CodeEditors90 G-Code90 PartIIIApplicationSoftware 7TheCartesianCoordinateSystem127 TheTableorMillTopology130 Lathe/RotaryTopology131 8CADandGraphics133 RastertoVectorConversionUtilities137 Differencebetween2Dand3D138 ListingofCADVendors138 GraphicsPrograms140 9CAMSoftware141 UnderstandingandUsingCAM144 GeneralizedMillingOptions151 CADandCAMCombinationSoftware155 PartIVBuildingorBuyingaCNCMachine 10ChoosingaReady-MadeCNCSystem159 Router/PlasmaTable166 MillsandLathes167 Do-It-Yourself(DIY)168 VendorListing168 11BuildingYourOwnCNCPlasmaTable171 PartVAppendices AProjectImplementationandExamples187 ExamplesofItemsthatCanBeProducedonaCNCRouter189 UnlimitedPossibilities218 ProgrammingExamples219 BProgrammingExamplesinG-Code225 Example1228 Example2229
ContentsVII CEngineeringProcessofSelectingaBallScrew231 DNEMAMotorMountingTemplates247 Index251

Preface UsingCNC,whetheronaprofessionalorhobbyistlevel,isnotonlyan excitingprocesstobeinvolvedinbutisalsothedirectionmanufac-turingisheading.Thereareagreatmanyfacetsandstagesinvolved intheend-to-endprocessofunderstandingandimplementingCNC,and,al-thoughtherehavebeenseveralbookspublishedonspecificaspectsortopics (suchasG-codeprogramming,buildingaCNCmachine,etc.),therehave beennobookswrittenthatguidethereaderthroughtheoverallprocess,that is,untilnow.Itisnottheintentofthisbooktoreplaceanypreviouslywritten informationonthistopicnortodelveintoanyparticulararea.However,by thetimereadersfinishreadingthisbook,theywillhaveasolidunderstanding oftheentireCNCprocessfromatop-downend-to-endperspective. Morespecifically,thisbookisintendedforthefollowingaudiences: Academic:Thisbookwillprovidetheinstructorandstudentsavery informativeintroductionintoappliedCNC,thevariousmachines, andtheiruses,alongwiththenecessarytoolsusedintheprocess. Businessowner:Theaspectofmovingasmall-tomedium-sizedbusi-ness,orevenastartupcompany,fromamanuallyconcentricman-ufacturingprocessintotheaccuracyandrepeatabilityofwhatCNC hastooffer,canbeadauntingtask.Thisbookguidesbusinessowners intheproperdirectiontohelpthemunderstandanddecidetheins andoutsofautomatingtheirmanufacturingprocess.Furthermore, alsodiscussedwillbewhattolookforwardtowhengrowingfuture CNC-basedoperations. Hobbyist:Thereareagreatnumberofindividualsinterestedinthe understandingandtechnicalaspectsofCNC,butarenotexactlysure wheretobeginwhatisabsolutelyrequiredfortheapplicationat handfrombothahardwareandsoftwareperspectiveandwhatis not.Therearemanyfreeandlow-costsoftwareoptionstochoose fromthatarelistedforthereadertoappropriatelydeterminewhatis neededfortheirparticularapplication. ix
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