Appearance of Wear during Milling
® Type of Wear –Flank and crater wear–Comb cracking and splintering
–Edge build-up
–Plastic deformation Flank and Crater Wear Range1.Flank wear 2.Crater wear 2 1 Crater width to cutting edge
2 2 Crater width
2.3 Crater depth
2.4 Crater length 1.1Angle chamfer/secondary cut
1.2Angle chamfer/main cut
1.3Main cut (average depth of cut)
1.4Depth of cut notch 1.11.21.31.4
2.12.22.32.4 Edge Build-up (Fig. 6)Edge build-up occursbecause of welding of
workpiece material to the
main cutting edge. It reduces
surface quality and extends
work times. Edge build-up
occurs mainly at lower
cutting speeds and depends
on the workpiece/cutting
material combination as well
as on cutting geometry.
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 1 Flank and Crater Wear Comb Cracking andSplinterings (Figs. 1, 2 and 3)The normal criterion is theflank wear. As with crater
wear, it is caused mainly by
abrasion. Excessive flank
wear produces poorer
surface finish, increases
cutting forces, and can lead
to insert breakage. The
magnitude of flank and crater
wear depends on carbide
grade, cutting speed, feed f (Figs. 4 and 5)Comb cracking arises due tothermal shocks on the cutter
during milling. Excessive
contact time can transform
comb cracking into
splintering of the cutting
edge. Formation of comb
cracks on the edge depends
on cutting speed, carbide
grade, cutting geometry, and
feed f
z z . and period of contact of
milling cutter manufacturers. Plastic Deformation (Fig. 7)Plastic deformation ariseswhen the rigidity of the
cutting material is so greatly
reduced by elevated cutting
temperatures that the cutting
forces deform the edge.
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