Staas & Halsey
Method of correcting error on involute interpolation
 An involute interpolation error correcting method corrects an error on involute interpolation in a numerical control system for machining gears and pump vanes. The method corrects an insufficient cut in an actual configuration of a workpiece which is machined along a first involute curve (In1) that is commanded. A radius of curvature (Rs) from a base circle (C) to a starting point (Ps3) of the insufficient cut on the first involute curve (In1), and an error (De) which occurs at an ending point of the first involute curve (In1) in a direction normal to the insufficient cut, are determined from the machined configuration, and set as parameters in the numerical control system. On interpolation from the starting point (Ps3) of the insufficient cut to the ending point (Pe1) of the first involute curve, a first offset at the time the first involute curve is interpolated is changed to a second offset which is increased from the first offset by the error (De). On interpolation up to a point (Ae1), the offset is restored to its original value. The configuration which is machined according to the above process is free of the insufficient cut. An excessive cut can be prevented when the offset is reduced. 
Fanuc Ltd.
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inventional additional inventional inventional
Toshiaki Takao Kunihiko Masafumi
Otsuki Sasaki Murakami Sano