DigitalF: Maschinenbau und MechatronikI: Fraunhofer AWZ CTMT
A. Gameros, L. Chiffre, H. Siller, Jochen Hiller, G. Genta
A reverse engineering methodology for nickel alloy turbine blades with internal features
CIRP Journal of Manufacturing Science and Technology, vol. 9, no. May, pp. 116-124
The scope of this work is to present a reverse engineering (RE) methodology for freeform surfaces, based on a case study of a turbine blade made of Inconel, including the reconstruction of its internal cooling system. The methodology uses an optical scanner and X-ray computed tomography (CT) equipment. Traceability of the measurements was obtained through the use of a Modular Freeform Gage (MFG). An uncertainty budget is presented for both measuring technologies and results show that the RE methodology presented is promising when comparing uncertainty values against common industrial tolerances.
F: Maschinenbau und MechatronikI: Fraunhofer AWZ CTMT
Jochen Hiller, G. Genta, G. Barbato, L. Chiffre, R. Levi
Measurement Uncertainty Evaluation in Dimensional X-ray Computed Tomography Using the Bootstrap Method
International Journal of Precision Engineering and Manufacturing, vol. 15, no. 4, pp. 617-622
Industrial applications of computed tomography (CT) for dimensional metrology on various components are fast increasing, owing to a number of favorable properties such as capability of non-destructive internal measurements. Uncertainty evaluation is however more complex than in conventional measurement processes, e.g., with tactile systems, also due to factors related to systematic errors, mainly caused by specific CT image characteristics. In this paper we propose a simulation-based framework for measurement uncertainty evaluation in dimensional CT using the bootstrap method. In a case study the problem concerning measurement uncertainties was addressed with bootstrap and successfully applied to ball-bar CT measurements. Results obtained enabled extension to more complex shapes such as actual industrial components as we show by tests on a hollow cylinder workpiece.