Endmill troubleshooting chart

BURR BREAKAGE CHIPPING CHIP PACKING CHATTERING

NO DIMENSIONAL ACCURACY NO PERPENDICULAR SIDE ROUGH SURFACE FINISH SHORT TOOL LIFE (DULL TEETH) WEAR

PROBLEM	CAUSE	SOLUTION
BURR	Too much wear on primary relief	Regrind sooner
	Incorrect condition	Correct milling condition
	Improper cutting angle	Change to correct cutting angle

PROBLEM	CAUSE	SOLUTION
BREAKAGE	Feed too fast	Slow down feed
	Too large cutting amount	Adjust to smaller cutting amount per teeth
	Too long flute length or long overall length	Hold shank deeper, use shorter end mill
	Too much wear	Regrind at earlier stage

PROBLEM	CAUSE	SOLUTION
CHIPPING	Feed too fast	Slow down to proper feed
	Feed too fast on first cut	Slow down on first bite
	Not enough rigidity of machine tool & holder	Change rigid machine tool or holder
	Loose holder	Tighten tool holder
	Loose holder (workpiece)	Tighten workpiece fixture
	Lack of rigidity (tool)	Use shortest end mill available. hold shank deeper. try down cut
	Teeth too sharp	Change to lower cutting angle, primary relief

PROBLEM	CAUSE	SOLUTION
CHIP PACKING	Too great a cutting amount	Adjust feed or speed
	Not enough chip room	Use end mill fewer flutes
	Not enough coolant	Apply more coolant. use air pressure

PROBLEM	CAUSE	SOLUTION
CHATTERING	Feed and speed too fast	Correct feed and speed
	Not enough rigidity (machine & holder)	Use better machine tool or holder or change condition
	Too much relief angle	Change to smaller relief angle. add margin (touch primary with oil stone)
	Loose holder (workpiece)	Hold workpiece tighter
	Cutting too deep	Correct to smaller cutting depth
	Too long flute length or long overall length	Hold shank deeper, use shorter end mill or try down cut

PROBLEM	CAUSE	SOLUTION
NO DIMENSIONAL ACCURACY	Too tough condition	Change to easier condition
	Lack of accuracy (machine & holder)	Repair machine or holder
	Not enough rigidity (machine & holder)	Change machine or holder or condition
	Not sufficient number of flutes	Use end mill with greater number of flutes

PROBLEM	CAUSE	SOLUTION
NO PERPENDICULAR SIDE	Feed too fast	Slow down to correct feed
	Too great a cutting amount	Reduce cutting amount
	Too long a flute length or long overall length	Use proper length tool. hold shank deeper
	Not sufficient number of flutes	Use end mill with greater number of flutes

PROBLEM	CAUSE	SOLUTION
ROUGH SURFACE FINISH	Feed too fast	Slow down to correct feed
	Slow speed	Use higher speed
	Too much wear	Regrind earlier stage
	Chip biting	Cut less amount per pass
	No end tooth concavity	Add margin (touch primary with oilstone)

PROBLEM	CAUSE	SOLUTION
SHORT TOOL LIFE (DULL TEETH)	Too much cutting friction	Regrind at earlier stage
	Tough work material	Select premium tool
	Improper cutting angle	Change cutting angle & primary

PROBLEM	CAUSE	SOLUTION
WEAR	Speed too fast	Slow down, use more coolant
	Hard material	Use higher grade, tool material, add surface treatment
	Biting chips	Change feed speed to change chip size or clear chips with coolant or air pressure
	Improper feed speed (too slow)	Increase feed speed. try down cut
	Improper cutting angle	Change to correct cutting angle
	Too low a primary relief angle	Change to larger relief angle