Closed Loop


Typically, the manufactured tooth flanks are not perfect: they exhibit errors:
Some errors are caused by the tool that cannot be corrected without a tool modification: typically profile crowning (Ca); these are not covered here. Other errors are caused by the machine itself, which is especially true of older mechanical machines, and / or the part installation.
Assuming part installation does not change significantly, Spiral / Helix angle, Pressure angle, Bias, Twist and Lengthwise crowning errors can be eliminated by the HyGEARS Closed Loop function.
For example, a Z13 spiral bevel pinion is face-milled on a 5Axis CnC machine. Measurement after the 1st cut shows the following results:
After the application of one Closed Loop iteration, the following result is obtained where virtually all errors, apart from the Profile crowning (Ca), have been eliminated. 
Closed Loop can be used on all HyGEARS supported gear types, whether Face Milled or simply milled.
The figure below illustrates the data flow when Closed Loop is applied in combination with the HyGEARS  5Axis CnC post-processor.
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