Page 194 - Gear Technology Solutions

The new process therefore utilizes a modified cutter head design with a very small
or zero blade spacing value between the leading outside blade and the following
inside blade. Zero blade spacing is possible if the same blade is used for example
with its outside edge as an outside blade and with its inside edge as inside blade.
Zero blade spacing is also possible if two “half blades” were mounted next to each
other in the same slot. The preferred embodiment however is the design of a dou-
ble slot which contains both an outside and an inside blade with a small spacing
angle WAME. This case makes it possible to prepare both blade kinds with posi-
tive side rake angles for an optimal chip removal process.

The following calculations are required to compute the final blade radii as well as
the generating gear axis set-over angle.

The final slot width angle is:
SLTW = p/Z (1)

The slot width cut by plunging with DRCOW = 0 depends only on the blade spac-
ing angle WAME, the number of cutter starts ZC and the number of coupling teeth Z:

SLCT = [(WAME * ZC)/ Z] (2)

The stock allowance angle is chosen between 0 and (SLTW-SLCT):

SCST = 0.6mm/RM (3)

The maximal increase of the outside blade radius and the maximal reduction of
the inside blade radius in order to leave the desired stock allowance after plunging
is:
DRMAX = [(SLTW-SLCT-SCST) / 2] * RM (4)

The effective radii increase and reduction has to be equal or smaller than DRMAX:

DRCOW… calculated for desired length crowning
If DRCOW > DRMAX → DRCOW = DRMAX (5)

The inside blade and outside blade cutter radius calculation at the reference point
is calculated as:
RWIB = RW0 – DRCOW (6)
RWOB = RW0 + DRCOW (7)

Although the radius difference has to be considered for leaving the desired stock
allowance value when cutting the first (convex flank), it has no influence on the
generating gear axis set-over rotation DW12Z:

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