Turning Troubleshooting

Flank Wear Crater Wear Built-up Edge
Flank wear Crater wear Built-up edge
Chipping DOC Notching Thermal Cracks Fracture
Chipping 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