Page 372 - Gear Technology Solutions

Figure 19. The DRW blade point radii correction, which was used in the pre-
revision software to maintain the correct tooth thickness, causes the length
crowning, which is more visible on the convex flank.

Figure 19: Standard CAGE download file, part cut with 12° cutter slot inclina-
tion and 3-face blade with blade calculation before software revision

As a first step to represent the 3-face blade geometry and subsequently the
flank geometry of the manufactured gears, a file that contains the effective
blade geometry was created (so called A3F-file). The same 3-face cut pinion
measured before with the standard CAGE download file (Figure 19) was also
measured with a download file, generated with the new A3F-file. The results of
this measurement are shown in Figure 20. This measurement achieved a Sum
of Errors Squared of 0.000 000 20inch² with corner point deviations in the sin-
gle micron range, which is an excellent result.

However, the intention of using 3-face blades is the improvement of the cutting
conditions, without changing the initially developed flank surfaces. If the A3F-
file was used to re-run the tooth contact analysis, then small changes in the
path of contact bias direction as well as changes in the length crowning
amount could be observed.

The development goal of the revised TREFACE software was to eliminate or
reduce any differences between 2-face and 3-face blades and subsequently
eliminate the differences between cutter heads with different slot inclination.

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