Turning Troubleshooting

Flank Wear Crater Wear Built-up Edge Chipping
Flank
wear
Crater
wear
Built-up
edge
Chipping
DOC Notching Thermal Cracks Fracture
Depth-of-cut
notching
Thermal
cracking
Fracture

PROBLEM CAUSES SOLUTIONS
POOR SURFACE FINISH Feed
rate too great for nose radius
Reduce
feed rate
Use
larger nose radius insert
Low
cutting speed
Increase
cutting speed
Poor
shearing action
Select
more positive chipbreaker
Flood
cutting zone with coolant
PROBLEM CAUSES SOLUTIONS
WORKPIECE CHATTER / VIBRATION Poor
Set-Up
Use
sharp inserts
Improper
insert selection
Select
more positive chipbreakers
Increase
feed rate
Increase
lead angle
Use
smaller nose radius tools
PROBLEM CAUSES SOLUTIONS
UNACCEPTABLE
CHIP CONTROL
Chip
too thin
Increase
feed rate
Use
more positive chipbreaker
Select
smaller nose radius insert
Decrease
lead angle
PROBLEM CAUSES SOLUTIONS
POOR
INSERT LIFE – Flank Wear
Excessive
heat
Reduce
cutting speed.
Flood
cutting zone with coolant
Select
more positive rake chipbreaker
Work
material microstructure contains carbides
Use
harder carbide grade
PROBLEM CAUSES SOLUTIONS
POOR INSERT LIFE – Crater Wear Excessive
heat at chip/tool interface
Reduce
cutting speed
Flood
cutting zone with coolant
Select
more positive rake chipbreaker
PROBLEM CAUSES SOLUTIONS
POOR INSERT LIFE – Built-up Edge Poor
shearing action
Use
sharp edge inserts
Use
grades with high lubricity surfaces (PVD coated grades, cermet grades,
polished carbide grades)
Use
coolant to reduce chip adherence when cutting gummy materials
High
cutting forces
Use
more positive chipbreaker
Low
cutting speed
Increase
speed
PROBLEM CAUSES SOLUTIONS
POOR INSERT LIFE – Chipping Chatter,
vibration
Use
sharp inserts
Select
more positive chipbreakers
Increase
feed rate
Increase
lead angle
Use
smaller nose radius tools
Built-up edge Increase
speed, use PVD coated grade, use coolant
Decrease
feed per tooth
Excessive cutting force Use
hone or T-land
Use
tougher grade
Select
stronger chipbreaker
PROBLEM CAUSES SOLUTIONS
POOR
INSERT LIFE – Depth of Cut Notching
Scale
part
Increase
lead angle
Increase
cutting speed
High work hardening materials Select
tougher grade
Select
stronger chipbreaker
Vary
depth of cut if possible
PROBLEM CAUSES SOLUTIONS
POOR INSERT LIFE – Thermal Cracks Extreme
variation in cutting temperature
Reduce
feed rate
Increase
cutting speed
Interrupted
cut
Use
stronger chipbreaker
PROBLEM CAUSES SOLUTIONS
POOR
INSERT LIFE – Fracture
Extreme
cutting conditions, excessive cutting force, chatter
Reduce
feed rate
Select
tougher grade
Select
stronger chipbreaker
Make
sure set-up is as rigid as possible