Page 398 - Gear Technology Solutions

29 Cutter and Blade Consolidation

29.1 Motivation for Cutter Consolidation

Consolidation of the blade geometries of a number of jobs has already been
done in the past. In the past, the software only copied the cutter data from one
job, which was selected as master job, from the data files which contained the
machine settings, cutter geometry and kinematic data of the consolidation va-
riety. The gear engineer had to correct each consolidated job manually, which
was time consuming and had a high potential of not delivering optimal results.

The newly developed cutter consolidation software allows the user to either
define a master job or to use the optimally suitable virtual master. The consoli-
dation calculates the optimal values for the common pressure angle, top width,
edge radius, curved blade radius and protuberance. The tooth thicknesses are
kept correct for each of the jobs and the original tooth contact of each of the
jobs is reestablished by a sophisticated procedure of basic setting changes. As
a result, only certain variations in cutting depth have to be accepted. Due to
the choice of a virtual master for pinion and gear and because of the split be-
tween shallower and deeper cutting, the delta values for depth are minimized.

The first new cutter consolidations are already in production. This chapter ex-
plains the complex functionality behind this new bevel gear production soft-
ware.

29.2 The Basic Consolidation Principle

Bevel and hypoid gears can be cut in a single indexing process (face milling)
or in a continuous indexing process (face hobbing). The bevel gear cutting
processes position the cutter head in space such that the silhouette of the cut-
ter blades represents one tooth of the generating gear while the cutter rotates.
Common face cutters for bevel gear cutting have several blade groups with
each having between one and four blades. Most common are alternating
(completing) cutters like the cutter shown in Figure 1 having one outside blade
and one inside blade per blade group. The blades are sticks with a five-sided
cross section [1]. Also sticks with rectangular cross section can be applied.

In many industrial applications, certain gearset designs (jobs) belong to a part
family. The term part family implies a group of gearsets which are very similar

383