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The integration of silicon micro probing systems into conventional gear measuring instruments (GMIs) allows fully automated measurements of external involute micro spur gears of normal modules smaller than 1 mm. This system, based on a silicon microprobe, has been developed and manufactured at the Institute for Microtechnology of the Technische Universität Braunschweig. The microprobe consists of a silicon sensor element and a stylus which is oriented perpendicularly to the sensor. The sensor is fabricated by means of silicon bulk micromachining. Its small dimensions of 6.5 mm × 6.5 mm allow compact mounting in a cartridge to facilitate the integration into a GMI. In this way, tactile measurements of 3D microstructures can be realized. To enable three-dimensional measurements with marginal forces, four Wheatstone bridges are built with diffused piezoresistors on the membrane of the sensor. On the reverse of the membrane, the stylus is glued perpendicularly to the sensor on a boss to transmit the probing forces to the sensor element during measurements. Sphere diameters smaller than 300 µm and shaft lengths of 5 mm as well as measurement forces from 10 µN enable the measurements of 3D microstructures. Such micro probing systems can be integrated into universal coordinate measuring machines and also into GMIs to extend their field of application. Practical measurements were carried out at the Physikalisch-Technische Bundesanstalt by qualifying the microprobes on a calibrated reference sphere to determine their sensitivity and their physical dimensions in volume. Following that, profile and helix measurements were carried out on a gear measurement standard with a module of 1 mm. The comparison of the measurements shows good agreement between the measurement values and the calibrated values. This result is a promising basis for the realization of smaller probe diameters for the tactile measurement of micro gears with smaller modules.

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This paper reports on the potential of microelectrical discharge machining (lEDM) as an innovative method for the fabrication of 3D microdevices. To demonstrate the wide capabilities of lEDM two different microsystems-a microfluidic device for the dispersion of nanoparticles and a star probe for microcoordinate metrology-are presented. To gain optimized process conditions as well as a high surface quality an adequate adaption of the single erosion parameters such as energy, pulse frequency and spark gap has to be carried out and is discussed below. Thus, a surface roughness of R a = 80 nm is achieved at the channel bottom. The fabricated stylus elements for the star probe have sphere diameters of 40-200 lm. For further surface quality enhancement a subsequent electrochemical polishing step is investigated. In case of the dispersion micromodule a combined process chain of lEDM-milling and electropolishing has reached a surface improvement above 70%.

This paper deals with the development of a coordinate measuring machine for parallel tactile probing of microstructures. The particular challenges due to the parallel probing will be discussed and the concluding results regarding the construction, the control and the simulation environment will be outlined.

Three-dimensional micro probing systems based on silicon force sensors allow force measurements in the range of several µN. Their high sensitivity enables tactile measurements of three-dimensional micro-and nanostructures without leaving strong traces on the probed surfaces. However, their small sizes of 6.5 mm x 6.5 mm do not allow an easy handling and can lead to a breakage of the complete system rapidly. To improve the handling and the integration of these micro probing systems a new kind of probe head and an appropriate assembling method have been developed. In order to show the performance and the high reproducibility of microprobes for their use in coordinate metrology, many measurements have been carried out with a customary gear measuring instrument on a calibrated spur gear. The results have been compared to calibration values and the deviations are in the range of maximum some 100 nm.

Zusammenfassung Maß- und Formmessungen an Gewinden, Zahnrädern oder anderen lückenbehafteten Bauteilen werden häufig in Zweiflankenanlage durchgeführt. In dem vorliegenden Beitrag werden bisher oft vernachlässigte Einflüsse durch diese Art der Messpunktaufnahme beschrieben und Lösungsmöglichkeiten zur Genauigkeitssteigerung aufgezeigt. Ein wesentlicher Bestandteil ist hierbei das neu entwickelte Lückennormal.