| Problem |
Causes |
Solutions |
| Hole
expansion |
Run 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 |
| Problem |
Causes |
Solutions |
| Irregular
hole size |
Non-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 high |
Decrease feed rate |
| Not enough lubrication |
Use drill with an oil hole |
| Problem |
Causes |
Solutions |
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 material |
Select 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 |
| Problem |
Causes |
Solutions |
Hole
perpendicularity
 |
Excessive tool wear |
Regrind |
| Low position accuracy |
Increase position accuracy |
Non-symmetric point angle
Large lip height
Run out of chisel edge |
Regrind correctly
Check precision after regrinding |
| Not enough drill rigidity |
Increase drill rigidity |
Drilling surface is not
horizontal
Poor alignment (for lathing) |
Work piece must be horizontal
Make a center hole. Check alignment |
| Problem |
Causes |
Solutions |
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 large |
Regrind correctly |
| Low drill rigidity |
Use carbide drill or larger web
drills |
| Problem |
Causes |
Solutions |
| Poor
surface finish |
Poor regrinding |
Take 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 high |
Reduce feed rate |
Excessive tool wear
Build up on margin is too large |
Regrind correctly
Select a coated tool |
| Chip packing |
Select suitable drill (wide
flute, high helix oil hole drill). Change cutting conditions (feed rate or
adopt step drilling) |
| Problem |
Causes |
Solutions |
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 low |
Increase the feed rate |
| Problem |
Causes |
Solutions |
Drill
breakage
 |
In accurate machine
Work material deformation |
Increase the rigidity of machine,
drill and work clamping |
| Relief angle is too small |
Regrind correctly |
| Feed rate is too high |
Decrease the feed rate |
| Excessive tool wear |
Regrind |
| Chip packing |
Select suitable drill (wide
flute, high helix oil hole drill). Change cutting conditions (feed rate or
adopt step drilling). |
| Difficulty entering the material |
Select 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 |
| Problem |
Causes |
Solutions |
Chipping
of corner edge
 |
In appropriate tool material |
Choose suitable tool material |
| Uneven hardness distribution on
the work material |
Iso static treatment
Change tool, material & cutting conditions, machining method (EDM) |
| Cutting or feed speed is too high |
Reduce cutting speed or feed |
| Not enough coolant |
Change lubrication method |
| Problem |
Causes |
Solutions |
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 small |
Regrind correctly |
| Tool material is not suitable |
Choose suitable tool material |
| Cutting speed or feed is too high |
Reduce cutting speed or feed |
| Problem |
Causes |
Solutions |
Abnormal
wear on corner part
 |
Tool late regrinding |
Regrind after a shorter time of
use |
| Bad alignment (for lathe turning) |
Check/adjust the alignment |
| Cutting speed too high |
Decrease the cutting speed |
| Point dimensions are not suitable |
Select correct point dimensions |
| Tool materials not suitable |
Choose suitable tool material |
| Coolant is not suitable |
Change coolant |
| Problem |
Causes |
Solutions |
| Large
wear and chipping, crushing of the chisel edge |
Feed rate is too large |
Decrease feed rate |
| Point dimensions are not suitable |
Select correct point dimensions |
| Tool materials is not suitable |
Choose suitable tool material |
| Relief angle is too small |
Increase relief angle |
| Problem |
Causes |
Solutions |
| Chipping of
margin |
Bush diameter is too small
Chip packing between drill & bush |
Select correct bush diameter or
select drill with chip breakers |
| Problem |
Causes |
Solutions |
| Margin
built-up |
High heat generation due to large
wear on the cutting edge |
Regrind |
| Lubrication is insufficient |
Change lubrication method |
| Coolant is not suitable |
Change coolant |
Bad chip ejection
Ductile material |
Change drill or the cutting
conditions |
| Problem |
Causes |
Solutions |
Tang
breakage
 |
Shank slippage due to some kind
of defect |
Take off the defect by honing the
surface |
| Defect of the inner surface of
Morse taper holder |
Change holder or correct the
surface of Morse taper holder |
| Low accuracy of regrinding |
Regrind correctly |
| Problem |
Causes |
Solutions |
| Noise
of chattering |
Relief angle is too big |
Grind a smaller relief angle |
| Low rigidity of the tool |
Use drill with high rigidity |
| Problem |
Causes |
Solutions |
| Chip rolled
around the drill |
Low extended and curly chips
Chips are stubbed in the flute |
Change drill and cutting
conditions |
| Problem |
Causes |
Solutions |
| One
side wear |
Large run out after attached to
machine |
Check holder and/or select
another one
Check run out after fixing to the chuck |
| Bad alignment (for lathe turning) |
Check/adjust the alignment |
