Assessment of Geometrical Deviations of Machined Part by Using Coordinate Measuring Machines

Abstract:

Currently, geometric deviations of machined parts can be measured following the recommendations outlined in ISO standards such as ISO-12780, ISO-12781, ISO-12180 and ISO-12181. Coordinate measuring machines have now become widely used for inspection hence the tracing and probing strategies recommended in these standards have become much more important. Unfortunately, only minimum number of sections and points are mentioned. Generally, in each section, only a single point will be sampled for the inspection processes. However, the interval between each pair of sampling points has to be smaller than half of the wavelength of the machined surface. Hence, in this research, a method for determining a suitable number of sampling sections and points for geometrical deviation assessment of machined parts made from CNC machining centers is introduced. In this method, the wavelength of a machined surface is predicted from the results of tests used to assess machine performance. Using Finished Test Pieces in ISO 10791-7-A160 as a case study, experimental results indicated that the number of assessed sections and points, calculated according to the introduced method, can be used for accurate measurements of the geometrical deviations of machined parts.

• Periodical: Key Engineering Materials (Volumes 656-657)
• Pages: 174-179
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.656-657.174
• Online since: July 2015
• Authors: Phaireepinas Phimpisan*, Chatchapol Chungchoo
• Keywords: Assessment, Coordinate Measuring Machine, Geometrical Deviation, Machined Part

References

[1] Dimensioning and Tolerancing, ASME Y14. 5-2009. NY: American Society of Mechanical Engineers. 2009. ISBN 0-7918-3192-2.

[2] D. Flack, Measurement Good Practice Guide: CMM Measurement Strategies, National Physical Laboratory, U.K., (2001).

[3] N. Khumbumrung, Geometric Dimensioning & Tolerancing - Fundamental Concept & Application I, N-Tris Solutions & Engineering Co., Ltd., Thailand, (2010).

[4] G. Henzold, Geometrical Dimensioning and Tolerancing for Design, Manufacturing and Inspection, Oxford, U.K., (2006).

DOI: 10.1016/b978-075066738-8/50000-x

[5] Shaw C. Feng, Theodore H. Hopp, A Review of Current Geometric Tolerancing Theories and Inspection Data Analysis Algorithms, Factory Automation Systems Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-0001, February (1991).

DOI: 10.6028/nist.ir.4509

[6] Data Processing System for Manual/CNC CMM: MCOSMOS, Mitutoyo, Catalog No. E4180-525, Unknown Date.

[7] Lai, K. And Wang J., A Computational Geometry Approach to Geometric Tolerancing, Proc. Of the XVI North American Manufacturing Research Conference, May 1988, 376-379.

[8] Etesami, F. and Qiao, H., Analysis of Two-dimensional Measurement Data for Automated Inspection, J. Of Manufacturing Systems, Vol. 9, NO. 1, 1990, 21-34.

DOI: 10.1016/0278-6125(90)90066-q

[9] Chetwynd, D.G., Application of linear programming to engineering metrology, Proc. Of the Inst. Of Mechanical Engineers, 1985, 93-100.

[10] ISO 10791-7: 1998 (E) Test Conditions for Machining Centres – Part 7: Accuracy of A Finished Test Piece.

DOI: 10.3403/01371743