Beschreibung
Tactile coordinate metrology has become a key technology to inspect 3D geometries in ranges from sub-micrometers up to meter sizes with high accuracy. With this purpose, workpiece surfaces are probed point by point in a coordinate measuring machine (CMM) using a probing system or probe. Micro-measurements are performed in special micro-CMMs with microprobes to allow the use of smaller probing elements, resulting in critical interactions with the workpiece. However, such devices are still only accessible to a few users. Based on earlier investigations on membrane-based microprobes, a novel 3D microprobe design was developed to allow micro-measurements in conventional CMMs. Composed of three micro-fabricated measuring cells forming an isotropic serial kinematics, this microprobe offers a compact solution with an outer dimension of Ø 11 mm. The parallelogram structure made of thin silicon hinges of the measuring cell allows large deflections of up to 600 µm in all three directions and low probing forces < 30 mN for 100 µm deflections. These miniaturized load cells use piezoresistive sensors diffused into the silicon hinges to measure the deflection with sub-micrometer accuracy and resolution. In this work, the novel and patented 3D microprobe design, its micro-fabrication, and a complete mechanical analysis are presented and discussed. Extensive characterization experiments confirmed the predictions of the theoretical analysis and provide design rules for also reaching future targeted properties of this novel class of microprobes. Finally, the successful integration and evaluation of the microprobe based on measurements of a gear standard in a CMM are reported, thereby opening up new possibilities for micro-probing in conventional CMMs.
Herstellerkennzeichnung:
Shaker Verlag GmbH
Am Langen Graben 15a
52353 Düren
DE
E-Mail: info@shaker.de
