Page 349 - Gear Technology Solutions

contour change over the measurement length L of a0, while R+DR delivers the
profile change a1.

Figure 1: Profile variation depending on the radius change

If the results of a profile measurement are observed, the effect of the inverse
importance of radius variations has to be considered. A large profile curvature
R results in a small profile variation (crowning) a. The GABE software is the
analysis software on the Gleason GBX blade measurement machine [1].
GABE proposes a default tolerance for cutting edge radius variations of +/-
10% from the nominal radius.

In the case of R = 5000mm and L = 20mm the following calculation can be
made:
a = 5000 – (5000² – 10²) = 0.0100mm
1/2
0
a = 5500 – (5500² – 10²) = 0.0091mm
1/2
1
1/2
a = 4500 – (4500² – 10²) = 0.0111mm
2

Amount of permissible scattering to achieve a radius measurement result with-
in the tolerance:
Da1 = Ia0 – a1I = 0.001mm
Da2 = Ia0 – a2I = 0.00111mm

The results show that +10% radius is more critical because the deviation of the
profile is larger. For the amount of scattering allowed the GBX measurement
certainty of +/-0.00075mm can be used to define Damax as 0.0015mm.

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