Problem/Cause	Solution
Breakage
Feed is too heavy	Reduce feed rate
Cut is too heavy	Decrease width and depth-of-cut
Overhang of tool is too much	Hold shank deeper, use shorter end mill
Wear is too much	Regrind at earlier stage
Wear
Speed is too fast	Decrease spindle speed, use another coolant
Hard work material	Use Coatings (TiN, TiCN, TiAlN)
Improper speed and feed (too slow)	Increase feed and speed
Improper helix angle	Change tool to correct helix angle
Primary relief angle is too large	Change to smaller relief angle
Recutting chips	Change feed and speed, Change chip size or clear chips with more coolant or air pressure
Short Tool Life
Cutting friction is too much	Regrind at earlier stage
Hard work material	Use Coatings ( TiN, TiCN,TiAlN)
Improper helix and relief angle	Change to correct helix angle and primary relief
Chipping
Feed rate too heavy	Reduce feed rate
Feed too heavy on first cut	Reduce feed rate on first cut
Lack of rigidity (machine & holder)	Use better machine or tool holder or change parameters
Lack of rigidity (tool)	Use shorter tool, hold shank deeper, try climb milling
Tool cutting corner too sharp	Decrease primary relief and cutting angle, reduce radial width-of-cut
Chip Packing
Cut too heavy	Decrease width and depth-of-cut
Not enough chip clearance	Use end mill with less flutes
Not enough coolant	Use higher coolant pressure and reposition nozzle to point of cut or use air pressure
Burrs
Wear on primary relief is too much	Regrind earlier stage
Incorrect feed and speed rates	Correct cutting parameters
Improper helix angle	Change to correct cutting angle
Rough Surface Finish
Feed rate too heavy	Reduce feed rate
Cutting speed is too slow	Increase RPM
Wear is too much	Regrind at earlier stage
No end tooth concavity	Grind concave angle on bottom teeth
Recutting chips	Change feed and speed, change chip size or clear chips with coolant or air pressure
Chattering
Feed and speed too fast	Correct feed and speed
Lack of rigidity (machine & holder)	Use better machine or tool holder or change parameters
Poor set up	Improve clamping rigidity
Cut is too heavy	Decrease width and depth of cut
Overhang of tool is too much	Hold shank deeper, use shorter end mill
Lack of relief	Decrease relief angle, make margin: (touch primary with oil stone)
Side Wall Taper in Workpiece
Feed rate too heavy	Reduce feed rate
Overhang of tool is too much	Hold shank deeper , use shorter end mill
Too few flutes	Use multiflutes end mills, use end mill with higher rigidity
No Dimensional Accuracy
Cut is too heavy	Decrease width and depth of cut
Lack of accuracy (machine & holder)	Repair machine or holder
Rigidity is not enough (machine & holder)	Change machine or tool holder or change parameters
Too few flutes	Use multiflute end mills, use end mill with higher rigidity