Drilling Basics.ppt

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1、DrillingBasicsDrillingBasicsInfeedRateSpeedSurfaceFeetPerMinuteChipLoadRetractRateDrillingDepthMinimumFluteLengthCalculationInfeedRateFunctionof:ProductCharacteristicsMaterialTypeCopperContentStackHeightToolDesignHoleWallQualityRequirementsProductivityNeeds80S300SpeedFunctionof:MachineCapabili

2、tyMaterialTypeDrillBitDiameterTypicallyMeasuredInRevolutionsPerMinute(RPM)80S300SurfaceFeetperMinute(SFM)Definition:Thedistance(feet)thattheprimarycuttingedgecornertravelsperminute.Functionof:MachineCapabilitiesProductTypeCalculation:PrimaryCuttingEdgeRPMxpxDiameter(in)12SFM=SurfaceFeetperMinu

3、te(SFM)ProcessEffects:HighSFMconditioncanleadtoexcessiveheatgeneration.PoorHoleWallQuality!TypicalCuttingSpeeds600SFM-DoubleSidedFR-4500SFM-MultilayerFR-4400SFM-Polyimide300SFM-Copper/Invar/CopperChipLoadDefinition:Downwardverticaldistancetraveledperrevolution.Indicationoftheamountofmaterial(c

4、hips)removedperrevolution.Calculation:80S300FeedSpeedInfeed(ipm)Speed(rpm)ChipLoad=ChipLoadProcessEffects:PositionalAccuracyHoleWallQualityBreakage80S300FeedSpeedHelixAngle(g)ChiselAnglePrimaryAngle(a)CuttingLipPrimaryFacetChipFormationPrimaryFaceWearMeasurementPrimaryFaceWidth(Original)Wear%

5、PrimaryWear=WearPrimaryWidthPrimaryFaceWearPatternsPrematureCuttingEdgeWearPrematureCenterWearSFMTooHighSFMTooLowWearShouldBeFairlyEvenAcrosstheCuttingEdgesandCenteratOptimumCuttingSpeedRetractRateFunctionof:StackHeightMachineStabilityProductivityHoleWallQuality?80S300DrillingDepthPointAngle(Q

6、)MinimumAllowableDepthDiameter2*tan(Q/2)=RuleofThumb:MinimumFluteLengthRequirementsProductStackHeightDepthintoBack-upEntryMaterialChipClearanceMin.ChipClearanceEntryMtlThicknessProductStackHeightDepthintoBack-upRepointStockRemovalMinimumFluteLength+