Piezoresistive micro probes for in-line surface inspection in industrial production processes

Miniaturized probes made of single-crystal silicon with an integrated piezoresistive bridge combine high sampling rates and a low contact force. The force dependent deflection causes a change in the mechanical stress which is evaluated piezoresistively. Robust against different ambient conditions, the sensor closes a gap between AFM and a classic stylus instrument. The robustness of the sensor and its signal towards the influences of light and temperature changes, electro smog as well as against dust and process auxiliaries such as cutting oils, allows the use under production conditions (e.g. directly in the machining space of a cutting or milling tool).

Initial tests in an industrial manufacturing environment have been successful. After the scraping action, the cutter of the tool head is replaced by the cantilever probe and moved up to the freshly machined work piece (without its replacement) to record the surface profile in-situ. The MEMS micro probes are ideal for drilling holes and undercuts that cannot be measured with an AFM or profilometer. The low contact force required also allows the non-destructive measurement of components made ​​of plastic, for example micro-optical structures.
 
Contact: CiS Forschungsinstitut für Mikrosensorik und Photovoltaik GmbH
info@cismst.de