EMRP-IND59: Multi-Sensor Metrology for Microparts in Innovative Industrial Products

• Forschungsstelle: METAS
• Projektnummer: F-5111.30021
• Projekttitel Englisch: EMRP-IND59: Multi-Sensor Metrology for Microparts in Innovative Industrial Products

Schlüsselwörter (Englisch)

Microparts, dimensional metrology, micro coordinate measuring machine, computed tomography

Kurzbeschreibung (Englisch)

Microparts with complex geometries are becoming increasingly important for numerous industrial products found in many industries such as automotive, medical and telecommunications. The need for improved metrological capabilities in this field has been identified by several roadmap studies and has been expressed by instrument manufacturers and standardization bodies.
Having a very low measurement uncertainty, tactile microcoordinate metrology is very often the reference method for fast optical and volumetric computer tomography (CT) measurements. In order to increase the field of application for tactile methods it is necessary to develop smaller probes, better probe calibration methods and to study effects such as friction and wear between probe and work piece. Also new Monte-Carlo based methods for the estimation of the uncertainty of complex geometrical parameters will be developed. Further contacts to leading European high precision manufacturing companies will be established and the application field of the METAS μ-CMM will be enlarged.

This project is part of the European Metrology Research Programme (EMRP, http://www.euramet.org/index.php?id=emrp); it is partly funded by the European Union on the basis of Decision No 912/2009/EC.

Projektziele (Englisch)

The goal of this project is a significant improvement of state-of-the-art of tactile micro-coordinate measurements made with the METAS μ-CMM.
Probes with probing spheres smaller than 50 μm are developed. The form deviations of probing spheres can be characterized with an uncertainty below 10 nm. Friction and wear of different sample probe material combinations are quantitatively determined. Monte-Carlo based methods for the estimation of the uncertainty are implemented including also complex geometrical parameters. New contacts to the high precision industry and new fields of applica-tion are established.

Abstract (Englisch)

The project was very successful and has received broad industrial attention. All goals set for METAS were achieved and the results were presented at workshops and conferences. We developed new methods to polish rough EDM probes made out of tungsten carbide. Spheres with diameters as small as 50 µm, having smooth surfaces and low form deviations, were produced.

Friction and wear studies implemented on the micro-CMM using spherical diamond coated tungsten carbide tips showed a considerable increase in wear resistance. On aluminum samples wear was reduced by more than 4’000 times with respect to classical ruby probes.

A virtual model of the µ-CMM measurement process was developed and combined with Monte-Carlo simulations in order to estimate the measurement uncertainty of complex shape parameters for medical and watch parts.

A comparison among the partners proved and validated the new possibilities for single point probing and scanning. The comparison revealed also specific scanning problems at partner institutes which could be tasks for future research.

Umsetzung und Anwendungen (Englisch)

The very small spherical probes developed in this project with diameters as small as 50 µm allow measurements on even smaller structures using our micro-CMM. The calibration procedure for diameter and shape of small spherical probes was considerably improved and smaller measurement uncertainties were realized. As a result of the wear study stable diamond probes are now used within METAS on various metrology systems and the increased life time reduces probe and calibration costs.

The collaboration with partners from the Swiss industry was very much appreciated. Complicated objects were measured as demonstrators to show the new capabilities available at METAS. The project and the discussions with the project partners were fruitful for the build up of our CMM and CT knowledge which is now used to enter new fields at METAS.

Publikationen / Ergebnisse (Englisch)

1. Küng, A., Nicolet, A., & Meli, F. (2015). Study of wear of diamond-coated probe tips when scanning on different materials. Measurement Science and Technology, 26(8). http://doi.org/10.1088/0957-0233/26/8/084005
2. Küng, A., Meli, F., Nicolet, A., & Thalmann, R. (2014). Application of a virtual coordinate measuring machine for measurement uncertainty estimation of aspherical lens parameters. Measurement Science and Technology, 25(9). http://doi.org/10.1088/0957-0233/25/9/094011
3. Rudolf Thalmann, Felix Meli and Alain Küng, (2016) State of the Art of Tactile Micro Coordinate Metrology, Appl. Sci., 150; http://doi.org/10.3390/app6050150