Thread problems

Hole Problems

ProblemCausesSolutions
Hole expansionRun out of drill when attached to the machine
Loose hold
Check holder and/or select another one
Check run out after fixing to the chuck
Non-symmetric point angle
Different lip height
Run out of chisel edge
Regrind correctly
Check preciseness after reground
ProblemCausesSolutions
Irregular hole sizeNon-symmetric point angle
Large lip height
Run out of chisel edge
Margin wear is large
Regrind correctly
Check precision after regrind
Large run out after attached to the machine
Loose hold
Low work holding rigidity
Check holder and select another one
Check run out after fixing to the chuck
Feed rate to highDecrease feed rate
Not enough lubricationUse drill with an oil hole
ProblemCausesSolutions
Low position accuracy

Large run out when attached to the machine
Large spindle run out
Check holder and/or select another one
Check run out after fixing to the chuck
Run out when cutting materialSelect more rigid tool and machine
Increase work clamping rigidity
Select a low cutting resistance thinning
Use centering
Work piece should be horizontal
Use a drill bush
Low alignment accuracy (for lathing)Check alignment
ProblemCausesSolutions
Hole perpendicularity

Excessive tool wearRegrind
Low position accuracyIncrease position accuracy
Non-symmetric point angle
Large lip height
Run out of chisel edge
Regrind correctly
Check precision after regrinding
Not enough drill rigidityIncrease drill rigidity
Drilling surface is not horizontal
Poor alignment (for lathing)
Work piece must be horizontal
Make a center hole. Check alignment
ProblemCausesSolutions
Bad cylindrical accuracy
Non-symmetric point angle
Large lip height
Run out of chisel edge
Regrind correctly
Check precision after regrinding
Large run out after attached to machine
Loose hold
Low work holding rigidity
Check hole and/or select another one
Check run out after fixing to the chuck
Relief angle is too largeRegrind correctly
Low drill rigidityUse carbide drill or larger web drills
ProblemCausesSolutions
Poor surface finishPoor regrindingTake off all the wear
Not suitable coolant for the material
Not enough coolant
Change supply method; increase volume
Select higher coolant quality
Large run out after attached to machine
Loose hold
Check holder and/or select another one
Check run out after fixing to the chuck
Feed rate is too highReduce feed rate
Excessive tool wear
Build up on margin is too large
Regrind correctly
Select a coated tool
Chip packingSelect suitable drill (wide flute, high helix oil hole drill). Change cutting conditions (feed rate or adopt step drilling)
ProblemCausesSolutions
Bad cylindrical shape
Non-symmetric point angle
Large lip height
Run out of chisel edge
Large margin wear
Regrind correctly
Check precision after regrinding
Feed rate is too lowIncrease the feed rate

Drill Problems

ProblemCausesSolutions
Drill breakage

In accurate machine
Work material deformation
Increase the rigidity of machine, drill and work clamping
Relief angle is too smallRegrind correctly
Feed rate is too highDecrease the feed rate
Excessive tool wearRegrind
Chip packingSelect suitable drill (wide flute, high helix oil hole drill). Change cutting conditions (feed rate or adopt step drilling).
Difficulty entering the materialSelect high rigid tool & rigid machine
Increase work clamping rigidity
Select a low cutting resistance thinning
Use centering
Work piece should be horizontal
Use bush drill
ProblemCausesSolutions
Chipping of corner edge
In appropriate tool materialChoose suitable tool material
Uneven hardness distribution on the work materialIso static treatment
Change tool, material & cutting conditions, machining method (EDM)
Cutting or feed speed is too highReduce cutting speed or feed
Not enough coolantChange lubrication method
ProblemCausesSolutions
Chipping of cutting edge
Large run out after attached to machine
Loose hold
Check holder and/or select another one
Check run out after fixing to the chuck
Relief angle is too smallRegrind correctly
Tool material is not suitableChoose suitable tool material
Cutting speed or feed is too highReduce cutting speed or feed
ProblemCausesSolutions
Abnormal wear on corner part
Tool late regrindingRegrind after a shorter time of use
Bad alignment (for lathe turning)Check/adjust the alignment
Cutting speed too highDecrease the cutting speed
Point dimensions are not suitableSelect correct point dimensions
Tool materials not suitableChoose suitable tool material
Coolant is not suitableChange coolant
ProblemCausesSolutions
Large wear and chipping, crushing of the chisel edgeFeed rate is too largeDecrease feed rate
Point dimensions are not suitableSelect correct point dimensions
Tool materials is not suitableChoose suitable tool material
Relief angle is too smallIncrease relief angle
ProblemCausesSolutions
Chipping of marginBush diameter is too small
Chip packing between drill & bush
Select correct bush diameter or select drill with chip breakers
ProblemCausesSolutions
Margin built-upHigh heat generation due to large wear on the cutting edgeRegrind
Lubrication is insufficientChange lubrication method
Coolant is not suitableChange coolant
Bad chip ejection
Ductile material
Change drill or the cutting conditions
ProblemCausesSolutions
Tang breakage
Shank slippage due to some kind of defectTake off the defect by honing the surface
Defect of the inner surface of Morse taper holderChange holder or correct the surface of Morse taper holder
Low accuracy of regrindingRegrind correctly
ProblemCausesSolutions
Noise of chatteringRelief angle is too bigGrind a smaller relief angle
Low rigidity of the toolUse drill with high rigidity
ProblemCausesSolutions
Chip rolled around the drillLow extended and curly chips
Chips are stubbed in the flute
Change drill and cutting conditions
ProblemCausesSolutions
One side wearLarge run out after attached to machineCheck holder and/or select another one
Check run out after fixing to the chuck
Bad alignment (for lathe turning)Check/adjust the alignment

Cold-hardening – наклеп

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