Page 379 - Gear Technology Solutions

wide blades which of course introduced higher blade blank cost and longer
blade re-sharpening times.

27.2 The Demand for More Radial Flexibility

In the aircraft industry many existing bevel gear designs are based on five-cut
fixed setting developments which have been proven for many decades and
therefore are invaluable considering the high safety demands in this industry.
Additional factors for the preservation of fixed setting modified roll-based devel-
opments include the requirement to grind flanks and root fillets without metallurgi-
cal surface compromises like burning and other structural material changes. As a
result, Formate grinding of ring gears as well as the application of cutter and
grinding wheel tilt with highly asymmetric tool pressure angles for the contact
length control are still abandoned in this industry.

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Figure 4: Pentac Aero-RT cutter head with wide blades

With the desire of aircraft bevel gear manufacturers to enter the new era of
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high speed dry cutting (PowerCutting ), it was impossible to use the existing
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Pentac face milling cutters. The blade radius range provided by the existing
blade widths and by the radius difference between the completing and the
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nominal Pentac cutters was not sufficient to cover the required range of job
designs which are based on fixed setting modified roll developments.

In order to find an answer for the demand of high-speed dry cutting in the air-
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craft industry, Gleason developed the Pentac Aero cutter system. All Pen-
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tac Aero cutter heads have extra wide slots with identical slot bottom radii. The

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