第1页共8页编号：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1页共8页Machining:AnIntroductionIntermsofannualdollarsspent,machiningisthemostimportantofthemanufacturingprocesses.Machiningcanbedefinedastheprocessofremovingmaterialfromaworkpieceintheformofchips.Thetermmetalcuttingisusedwhenthematerialismetallic.Mostmachininghasverylowset-upcostcomparedtoforming,molding,andcastingprocesses.However,machiningismuchmoreexpensiveforhighvolumes.Machiningisnecessarywheretighttolerancesondimensionsandfinishesarerequired.TheMachiningsectionisdividedintothefollowingcategories:Drilling:IntroductionDrillingiseasilythemostcommonmachiningprocess.Oneestimateisthat75%ofallmetal-cuttingmaterialremovedcomesfromdrillingoperations.Drillinginvolvesthecreationofholesthatarerightcircularcylinders.Thisisaccomplishedmosttypicallybyusingatwistdrill,somethingmostreaderswillhaveseenbefore.Thefigurebelowillustratesacrosssectionofaholebeingcutbyacommontwistdrill:第2页共8页第1页共8页编号：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2页共8页Thechipsmustexitthroughtheflutestotheoutsideofthetool.Ascanbeseeninthefigure,thecuttingfrontisembeddedwithintheworkpiece,makingcoolingdifficult.Thecuttingareacanbeflooded,coolantspraymistcanbeapplied,orcoolantcanbedeliveredthroughthedrillbitshaft.Foranoverviewofthechip-formationprocess,seetheChipFormationSection.DrillingCharacteristicsThecharacteristicsofdrillingthatsetitapartfromotherpoweredmetalcuttingoperationsare:Thechipsmustexitoutoftheholecreatedbythecutting.Chipexitcancauseproblemswhenchipsarelargeand/orcontinuous.Fordeepholesinlargeworkpieces,coolantmayneedtobedeliveredthroughthedrillshafttothecuttingfront.Ofthepoweredmetalcuttingprocesses,drillingonadrillpressisthemostlikelytobeperformedbysomeonewhoisnotamachinist.DrillPressWorkAreaAviewofthemetal-cuttingareaofadrillpressisshownbelow.Theworkpieceisheldinplacebyaclampsincecuttingforcescanbequitelarge.Itisdangeroustoholdaworkpiecebyhandduringdrillingsincecuttingforcescanunpredictablygetquitelargeandwrenchthepartaway.Woodisoftenusedunderneaththepartsothatthedrillbitcanovershootwithoutdamagingthetable.Thetablealsohasholesfordrillovershootaswellasweightreduction.Athree-jawchuckisusedsincethreepointsdetermineacircleintwodimensions.Four-jawchucksarerarelyseensinceoffsetofthebitisnotnecessary.Thenextsectioncontainsillustrationsofdrillbitchucks.Togetanideaofthedifferingconfigurationsofthreeandfour-jawchucks,pleaseseetheequivalentlathechucks.第3页共8页第2页共8页编号：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3页共8页Turning:EngineLatheTurningisanotherofthebasicmachiningprocesses.Informationinthissectionisorganizedaccordingtothesubcategorylinksinthemenubartotheleft.ÂTurningproducessolidsofrevolutionwhichcanbetightlytolerancedbecauseofthespecializednatureoftheoperation.Turningisperformedonamachinecalledalatheinwhichthetoolisstationaryandthepartisrotated.Thefigurebelowillustratesanenginelathe.Lathesaredesignedsolelyforturningoperations,sothatprecisecontrolofthecuttingresultsintighttolerances.Theworkpieceismountedonthechuck,whichrotatesrelativetothestationarytool.第4页共8页第3页共8页编号：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4页共8页TurningTurningreferstocuttingasshownbelow.Theterm"facing"isusedtodescriberemovalofmaterialfromtheflatendofacylindricalpart,asshow...
