Probe Position Planning for Measuring Cylindrical Gears on a Four-Axis CNC Machine

Abstract

During large-size gear manufacturing by form grinding, the actual tooth surfaces will differ from the theoretical tooth surface because of errors in the clamping fixture and machine axes and machining deflection. Therefore, to improve gear precision, the gear tooth deviations should be measured first and the flank correction implemented based on these deviations. To address the difficulty in large-size gear transit, we develop an on-machine scanning measurement for cylindrical gears on the five-axis CNC gear profile grinding machine that can measure the gear tooth deviations on the machine immediately after grinding, but only four axes are needed for the measurement. Our results can serve as a foundation for follow-up research on closed-loop flank correction technology. This measuring process, which is based on the AGMA standards, includes the (1) profile deviation, (2) helix deviation, (3) pitch deviation, and (4) flank topographic deviation. The mathematical models for measuring probe positioning are derived using the base circle method. We also calculate measuring positions that can serve as a basis for programming the NC codes of the measuring process. Finally, instead of the gear profile grinding machine, we used the six-axis CNC hypoid gear cutting machine for measuring experiments to verify the proposed mathematical models, and the experimental result was compared with Klingelnberg P40 gear measuring center.