Page 319 - Gear Technology Solutions

The formula in Figure 14 for the calculation of the effective normal rake angle g
can be applied for the calculation of the sharpness conditions around the entire
blade front [3].

Figure 16: Effective normal rake angles around blade front

22.6 Multi-Face Blade Geometry

Chip packing is a phenomenon which is caused by insufficient chip flow, most-
ly after a first chip is caught in a small gap between blade and cutter. The first
chip might initiate additional chips to stay in the gap between two blades and
the accumulation of a chip packing as shown in Figure 17 to the left is the
possible result. Chip packing leads to catastrophic failures like blade breakage
if it is not recognized in time.

The Gleason patented back face grinding creates gaps in front of outside
blades on face milling cutters and in front of inside blades of face hobbing cut-
ters which open to the outside and therefore promote a free chip flow. The pa-
rameter for the back faces, Back Rake Angle e , Back Hook Angle h and
Back Face Distance DSF are proposed by the three-face summary program.
Figure 18 shows a graphic with the definitions of the back face angles.

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