Lyrfac - Fournisseur Industriel

Usinage - Fraisage - Indexable End Mill Troubleshooting

Chatter (lines or grooves at regular
intervals in machined surface)
Poor surface finish - roughness
Poor surface finish - flatness

Poor surface finish - waviness
Part burring
Workpiece breakout

Depth-of-cut notching

Thermal cracking


PROBLEM	CAUSES	SOLUTIONS

CHATTER (lines or grooves at regular intervals)	-Lack of rigidity	Check spindle & fixture rigidity

	-Excessive cutting force	Reduce feed rate, depth of cut or width of cut if excessive

	-Thin-walled part	Dampen part

PROBLEM	CAUSES	SOLUTIONS

POOR SURFACE FINISH - Roughness	-Insert worn	Use more wear resistant coated grade

	-Built-up edge	Increase speed, use PVD coated inserts, use coolant

	-High tooth	Correct improper preset. Set wiper

	-Wiper insert set too highy	.0005" to .002" above high insert

PROBLEM	CAUSES	SOLUTIONS

POOR SURFACE FINISH - Flatness	-Deflection	Check for deflection of part, cutter or spindle

	-Improper spindle tilt (milling machines)	Check spindle tilt - .0015" per foot is recommended

	-Excessive cutting force	Use a more positive rake cutter

	-Width of cut too large for cutter	Use a larger diameter cutter
HAUT	-Width of cut too large for cutter	Use a larger diameter cutter
PROBLEM	CAUSES	SOLUTIONS

POOR SURFACE FINISH - Waviness	-Advance per revolution greater than width of flat of insert	Deflection
POOR SURFACE FINISH - Waviness		Reduce feed rate

PROBLEM	CAUSES	SOLUTIONS

PART BURRING	-Insert worn	Use more wear resistant coated grade

	-Excessive insert edge prep	Reduce or avoid hone or T-land

	-Improper angle of entry or exit of cutter	Change position of center of cutter over part

	-Improper lead angle	Use larger lead angle; avoid 0° lead angle cutters

	-Chip load too great or too small	Increase or decrease chip load

PROBLEM	CAUSES	SOLUTIONS

WORKPIECE BREAKOUT	-Improper geometry	Use larger lead angle; avoid 0° lead angle cutters

		Use inserts with double facet corners

	-Improper angle of entry or exit of cutter	Change position of center of cutter over part

PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Flank Wear	-Excessive heat	Reduce speed. Increase chip load to carry away heat

		Use coolant

	-Incorrect grade	Use a more wear resistant coated grade

PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Crater Wear	-Excessive heat	Use a more heat resistant coated grade (Al2O3 layer)

		Reduce speed

		Flush with coolant
HAUT
HAUT	-Excessive cutting force	Reduce feed rate

PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Built-up Edge	Insufficient cutting temperature causes chip adherence to insert	Increase speed

		Use coolant to aid lubricity

		Use sharp edge inserts

		Use grades with high lubricity surfaces (PVD coated grades, Cermet grades, polished carbide grades)

PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Chipping	Chatter	Check spindle & fixture rigidity

		Reduce feed rate, depth of cut or width of cut if excessive

		Use sharp edge inserts; avoid hone or T-land

	Insufficient edge prep	Use hone or T-land

	Incorrect grade	Use tougher grade

	Built-up edge	Increase speed, use PVD coated grade, use coolant

	Excessive cutting force	Decrease feed per tooth

	Re-cutting chips	Use cutter with chip gullets large enough for chip clearance.

		Use air blast or coolant to remove chips.
PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Depth of Cut Notching	Scale part, high work hardening materials	Use larger lead angle; avoid 0° lead angle cutters

		Use more wear resistant grade

		Reduce feed per tooth

		Reduce speed

		Use T-land

		Vary depth of cut

PROBLEM	CAUSES	SOLUTIONS

POOR INSERT LIFE - Thermal Cracks	Heat stresses due to temperature variations	Reduce speed

		Use cutter with more positive geometry

		Use grade designed for use with coolant

		Discontinue coolant use