Involute microgears are important components used in industrial applications. Quality control benefits from enhanced, monitored measurement processes. Workpiece-like measurement standards help to verify measurements and estimate measurement uncertainties by comparing the geometrical values measured with the calibration values. To address the need for reliable, traceable gear standards on the microscale, Germany’s national metrology institute, the Physikalisch-Technische Bundesanstalt, has developed the first internal involute microgear measurement standard with modules between 0.1 and 1 mm. We manufactured two versions with different materials (titanium and carbide) by means of wire electrical discharge machining. Profile and flank deviations were calibrated with sub-micrometer uncertainty by means of tactile scanning measurements using a micro coordinate measuring machine. This paper features information on the design, manufacturing, and calibration processes, including a detailed measurement uncertainty budget.

This paper describes the experimental verification of the novel IMT-PTB microprobe combined with a uniquely designed microenvironment. The microprobe consists of three silicon-based parallelograms stacked orthogonally, which leads to high isotropy. The probe tip deflections are detected in 3D with the help of piezoresistors placed in the parallelograms. The microenvironment facilitates and improves the measurement of workpieces with sub-millimeter features. The new microprobe and the microenvironment were integrated into a commercial coordinate measuring machine (CMM). To evaluate the microprobe performance, PTB produced and calibrated three reference objects: a cube, a sphere, and a microgear measurement standard. The differences between the calibration values and the measurement results obtained by the microprobe were in the sub-micrometer range. Furthermore, the microprobe was compared with the standard probing system of the gear measuring machine by measuring the reference objects with identical parameters. The results show the excellent performance of the micro probing system, thereby extending the capability of the CMM for high-precision measurements of complex workpieces at the microscale.

This paper gives an overview of the field of clamping and gripping principles from the viewpoint of sample fixturing for dimensional metrology for microobjects. The requirements for clamping microcomponents that allow dimensional measurements are therefore explained before principles and solutions of microclamps as found in literature are reviewed and evaluated on basis of these requirements. Results show that there is no single superior clamping principle or method of implementation but rather several effective solutions for specific applications. The core value of this paper is the link between requirements for sample fixturing in dimensional micrometrology and the many approaches already investigated in the field of microclamping. A radar chart and a decision tree summarize and visualize the major aspects of this review. Finally, directions of future key research areas are suggested.

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Modern coordinate measuring machines (CMMs) feature high-precision scanning due to improved mechanics, electronics, control, and software. PTB's Coordinate Metrology department therefore executed a thorough experimental comparison of the performance of scanning and discrete point probing regarding involute gear calibrations. In the last four years, PTB used scanning and discrete point probing to calibrate 29 different gear geometries covering a wide range of industry-relevant workpieces. Based on these extensive experiments and their analysis regarding measurement results, uncertainty and time, PTB decided to use scanning for gear calibrations in the future while guaranteeing the same measurement uncertainties and the same high level of reliability. This paper comprises an overview of tactile CMM scanning technology, PTB's gear calibration strategy, the measurement results, measurement uncertainty analyses, and a discussion of the task-specific advantages and challenges of scanning.