World Congress Fundamental and Applied Metrology September 6 − 11 , 2009 , Lisbon , Portugal ADVANCED CALIBRATION METHOD FOR PITCH ARTIFACT
Abstract − The pitch measuring accuracy for gear measuring instruments (GMIs) is evaluated by measuring a calibrated artifact. We proposed a novel artifact which called multiball artifact (MBA). The MBA is composed of the pitch balls assumed to gear teeth and the reference axis assumed to a center axis of gear. The MBA can be calibrated more accurate than a conventional pitch artifact. When the MBA is calibrated, it is important to eliminate an error of measuring instrument; therefore we calibrate the MBA adapting the multiple-orientation technique. In the multipleorientation technique, the MBA is set up in difference orientations around the reference axis and the measurement error is eliminates by averaging the measurement value for all orientations. There are, however, Fourier components of the measurement error that can not be eliminated depending on the total number of orientations. In this paper, we propose the advanced calibration method; the error separation method for the multiple-orientation technique is improved and the total number of orientations can be reduced. The superiority of the proposed method is clarified from the calibration results using the MBA.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.
Tooth Form Evaluation Using Ball Artifact
ボールアーティファクトによって歯形測定機を校正する新たな方法の実現のため, 校正要素の1つであるボール中心間距離を100nm以下の不確かさで, 長さの国家標準にトレーサブルに測定する新しい方法を提案した. 開発した装置によって, 44mmのボール中心間距離を21nmの拡張不確かさで評価できた.