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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. 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.

Die and Mould - 7354 D

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