4第4章 (2/2)

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istinguishedthecoredifferencesbetweenmillingmachinesandlathes:lathesrotateworkpieceswithfixedtools,whilemillingmachinesrotatecuttersathighspeedwithworkpiecesfedsteadily.Millingmachinesaresuitableforprocessingplanes,grooves,steps,gears,keywaysandothercomplexshapeswithawiderrangeofapplications.
  

  

  
Withsolidtheoreticalknowledge,wemovedontobasicpracticaltraining,startingwithno-loadoperationofthemillingmachineandreadingcontrolofdialgauges.Accuratecontroloffeedrateisthecoreskillformillingworkers.Eachsmallgridonthehandwheeldialofthemillingmachinecorrespondstoafixedmovingdistance.Thehandwheelmustbeturnedevenly,slowlyandaccurately,andrecklessshaking,rapidfeedingandovertraveloperationsareforbidden.Atfirst,Iwasnotproficientinhandwheelcontrol,pronetoexcessivefeedandpositiondeviation,resultinginbenchmarkerrorsofworkpieces.Afterrepeatedpractice,Igraduallymasteredtheoperationrhythm,learnedtoreaddataaccuratelyandcontrolcuttingdepthaccordingtomachiningallowance,andskillfullycompletedprecisethree-axispositioningoftheworktable,greatlyimprovingthestabilityandaccuracyofoperation.
  

  

  
Aftermasteringbasicoperations,weofficiallycarriedoutmillingtrainingonworkpieces,focusingonthreefundamentalprocessingtechnologies:planemilling,stepmillingandright-anglegroovemilling.Beforeprocessing,Istrictlyfollowedthetechnologicalprocess.First,Iinspectedthedimensionofblankworkpiecesandremovedsurfaceoxidescale.ThenIplacedtheworkpieceintoabenchviceontheworktable,leveledtheworkpieceandclampeditevenlytoensurenolooseningoroffsetduringprocessing.Afterclamping,asuitableendmillingcutterandspindlespeedwereselectedaccordingtotheworkpiecematerialandprocessingrequirements.Lowrotatingspeedandlargefeedratewereadoptedinroughmachiningtoremoveexcessallowance,whilehigherrotatingspeedandsmallerfeedratewereusedinfinishmachiningtoguaranteethesurfacefinishofworkpieces.
  

  

  
Planemillingisthemostbasicworkingprocedure,aimingtoflattentheunevensurfaceofblanksandensuretheflatnessofthereferenceplane.Duringmyfirstmillingpractice,unevenmillinglinesandtooljointmarksappearedonthesurface.Undertheteacher'sguidance,Ifoundthattheproblemswerecausedbyunstablefeedspeedandinaccuratetoolsetting.Insubsequentoperations,Icompletedprecisetoolsettinginadvance,maintaineduniformfeeding,reasonablycontrolledcuttingdepthandconductedmultipleshallowcuttingpasses,whicheffectivelyimprovedthesurfacequalityofworkpieces.Inthepracticeofstepandgroovemilling,Imasteredtheprocessingideaoflayeredcuttingtoavoidexcessiveone-timecuttingdepththatwouldcausecutterwear,workpiecedeformationandburrsgeneratedbytoolchatter.Afterprocessing,Imeasuredthelength,widthanddepthofworkpieceswithcalipersandstraightrulers,comparedthedatawithtolerancerequirementsondrawings,andrepeatedlycorrectedmachiningerrors.Igradu