Page 363 - Gear Technology Solutions

Figure 10: Radial compensation of spacing discrepancy Fd

The initial gear design calculation either used a theoretical blade, or a standard
2-face blade design. Although the radial compensation of the 3-face blade will
re-establish the tooth thickness, there will be some side effects which are dis-
cussed in the following section.

26.3 Length Crowning and Flank Twist Phenomenon

The change from 2-face ground blades in Pentac®-FH cutter heads to 3-face
ground and all-around coated blades in Pentac®Plus-FH cutter heads also re-
quires a relocation of the blade front faces like described in the previous sec-
tion. Different front relocations of outside and inside blades cause a tooth
thickness change, which can be compensated with small changes of the inside
blade and outside blade radii as mentioned above. The alteration of the bade
point radii compared to the calculated values causes a major side effect which
is a length crowning error on both flanks (Figure 11, left side). The second
side effect relates to the change of the effective cutting edge hook angle ver-
sus the initial 2-face value (or theoretical blade definition) which results in a
flank twist (Figure 11, right side).

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