On-machine angle measurement of a precision V-groove on a ceramic workpiece

A technique for measurement of a prism apex angle by optical angle sensors with a reference artefact

“…In this paper, due to the limited facilities, the calibration of the reference prism could not be carried out. Meanwhile, according to the [35], the angle between two surfaces can be calibrated with a standard uncertainty of 1.80 arc-second with the employment of a commercial coordinate measuring machine (CMM); applying this value as a standard uncertainty of the apex angle of a reference prism in table 4 gives an expanded uncertainty U of 9.25 arc-seconds (k = 2, 95% confidence). It should be noted that the above result is with the developed oblique-incidence optical angle sensor and a commercial laser autocollimator for measurement of a target prism and a reference prism, respectively.…”

“…Measurement uncertainty analysis has also been carried out based on the GUM, and an expanded uncertainty (k = 2, 95% confidence) was evaluated to be √ u 2 θApex_R + (4.262) 2 arc-seconds, where u θ Apex_R is the standard uncertainty of the apex angle of a calibrated reference artefact. On the assumption that a calibrated reference artefact whose standard uncertainty of the apex angle is 1.80 arc-second [35] is employed, and is measured by the optical angle sensor identical to that developed in this paper, a combined measurement uncertainty of the proposed technique is expected to be 12.57 arc-seconds, which is enough to carry out the in-line evaluation of a commercial right-angle prism whose apex angle is fabricated with a tolerance of ±3 arc-minutes (±180 arc-seconds). Further verification of the proposed method through the comparison with conventional methods is the next step of the research, and will be carried out in future work.…”

On-machine diameter measurement of a cylindrical workpiece with a reference artefact

“…In recent years, strong demands on precision ceramic components can be found in many industrial fields [1][2][3][4] due to the characteristics of ceramic materials such as high hardness and low thermal expansion coefficient. Meanwhile, one of the drawbacks of ceramic components is the low machining efficiency due to their high hardness and brittle fracture characteristics [5,6].…”

“…To overcome the aforementioned problem, in this paper, a comparative measurement method with a calibrated reference artefact [2,21,22] is newly introduced to the onmachine measurement of a ceramic cylindrical workpiece. In the proposed method, a reference artefact (master cylinder) with identical material and nominal diameter with respect to a workpiece is employed, and measurement of the workpiece diameter is carried out by detecting its deviation from the diameter of the reference artefact, which is calibrated by using a high-precision measuring instrument such as a CMM in advance of the on-machine measurement; this enables the proposed method to evaluate the diameter of a workpiece while reducing the influence of the poor thermal stability of the optical micrometer.…”

“…After that, the comparative measurement method with a calibrated reference artefact is integrated into the on-machine measurement system. Measurement uncertainty of the proposed comparative measurement method is then evaluated through the uncertainty analysis of the CMM calibration of the reference artefact diameter based on a Monte Carlo method [2,23]. Regarding the requirement from the industry, the target value of the measurement uncertainty is set to 1.5 µm.…”