Using CMM data, HyGEARS calculates changes in machine settings needed to match the machined surface to the desired theoretical surface.

When introduced by The Gleason Works in the early 1980s, the process was referred to as Corrective Machine Settings. It is often termed as Closed Loop nowadays.

The top right picture displays the differences between the machined and theoretical surfaces of a 5.08 mm module, 19 tooth, 35 degree spiral angle spiral-bevel pinion after the initial cut.

First order errors in spiral and pressure angle are clearly visible, plus slight lengthwise crowning and bias.

The right bottom figure shows the same pinion, after Corrective Machine Settings were calculated and applied from the data shown in the top figure. Clearly, all significant errors have disappeared.

The Closed Loop process is equally applicable to standard gear cutting machines and 5 Axis CnC machines.