K. Ravindra, V. Chittaranjan Das, P. Madar Valli, D. Nageswara Rao
The geometric features of the manufactured components are inspected for their acceptability. Most of the machine parts consist of cylindrical form, which should possess the required geometrical tolerance and should be checked for their acceptance. At the present scenario, the Coordinate Measuring Machines (CMMs) are considered to be reliable and capable to perform automated inspection on the manufactured parts. In CMMs, the measured data is being processed using Least Squares Method to assess the geometric features of the part. The error values assessed by CMM are not the minimum, there by...
TC14 ISMQC 2007
· TC14
· 2007
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Dariusz Janecki, Stanislaw Adamczak, Krzysztof Stepien
Cylindrical surfaces are common in industrial machining so accurate evaluation of cylindricity is a very important application in geometrical quantities metrology. New GPS standards describe four measuring strategies: a cross-section method, a generatrix method, a point method and so-called “bird-cage” method. The first three methods are relatively well developed. The last one, however, the most accurate method has not been well described mathematically. The paper presents the mathematical model of calculating the cylinder axis orientation with the “bird-cage” strategy.
TC14 ISMQC 2007
· TC14
· 2007
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W. Jakubiec
The paper presents the methodology of analytical estimation of coordinate measurement uncertainty. The underlying assumption of this methodology is, that a measuring task is an indirect measurement, where measurands are not coordinates but differences of coordinates. The model used for analysis takes into account geometrical errors, kinematics and dimensions of the machine. The author defined the functions expressing maximum values occurring for differences of particular geometrical errors. The paper also demonstrates the models of several measuring tasks carried out on 2D machines with...
TC14 ISMQC 2007
· TC14
· 2007
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Dariusz Janecki, Stanislaw Adamczak, Krzysztof Stepien
Rotary elements constitute a large and important group of machine parts. They are common in various industries, for instance, automotive, steel and paper industries. This is the reason why the problem of accurate measurement of roundness deviation is one of the most important fields of the industrial application of surface metrology. According to the requirements of new Geometrical Product Specifications standards, correct determination of the roundness parameters requires the calculation of the location of the centre and the radius of the associated circle. Usually these values are...
TC14 ISMQC 2007
· TC14
· 2007
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M. Vedran, M. Sanjin, R. Biserka, M. SrĜan , B. Gorana
The usual estimation of the coverage factor k , using the Guide to the Expression of Uncertainty in Measurement - GUM method is based on the Central Limit Theorem and directly related to the Gaussian or t-distribution of probability of the measured value whose conditions in practice do not always have to be satisfied. The work studies especially the cases when one or several input values have a significantly higher contribution of uncertainty in relation to other input values. In such cases it is not clear whether the GUM method conditions have been met or not, which may sometimes lead to...
TC14 ISMQC 2007
· TC14
· 2007
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G. Rajamohan, M. S. Shunmugam, G. L. Samuel
Verification of engineering components having freeform profiles on a coordinate measuring machine (CMM) requires accurate measurement of sufficient number of sample points. While the measurement accuracy increases with increased sample size, it is often limited by cost and time considerations. Thus, for a given sample size, the locations of the measurement points are to be determined such that the actual shape may be effectively characterized. Several attempts are reported in the literature. A simple algorithm based on dominant points is proposed in this paper. Simulation studies have been...
TC14 ISMQC 2007
· TC14
· 2007
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Sanjeev Kumar, P. J. Thakar
Reverse Engineering Applications has become quite popular in the recent years. It has potential of duplicating the existing item with manual or computer aided means. This paper presents the computer aided reverse engineering approach for surface digitization and data evaluation using CMM. Digitize data is exported in a CAD software for creating a CAD model and data evaluation. Methodology is explained and two case studies are used to illustrate the approach.
TC14 ISMQC 2007
· TC14
· 2007
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Vít Zelený, Prokop Zelený
The Czech Metrological Institute in Prague started the research in the field of measurement of shapes, dimensions and position with the accuracy falling into the sub-micron field. It is being equipped with new measuring equipment and engages into international projects, such as, e. g. the project Nano CMM. On the other hand, after the experience with high prices of measuring technical equipment, the institute comes with the idea to offer the possibility of measurement for practically everybody. The Internet virtual multi-sensor measuring machine has been developed for processing and...
TC14 ISMQC 2007
· TC14
· 2007
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M. Abbe, M. Nara, K. Takamasu
A noble simulation method for evaluating task specific uncertainty in coordinate metrology is proposed. Provided that specification or test result conforming to ISO 10360-2 is available, both variance of point coordinates and covariance expressing the mutual influence is handled to perform Monte Carlo simulation reflecting spatial constraint in error of CMM. Development and implementation of the over all procedures are pursued to apply them on real CMM. Comparison result between uncertainties obtained by the proposed method and that by experimental measurements shows good agreement. However...
TC14 ISMQC 2007
· TC14
· 2007
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Albert Weckenmann, Teresa Werner
In coordinate metrology, the operator has a significant influence on the measurement result. Therefore an adequate qualification for the correct performance of measurement tasks is a necessary precondition for reliable measurement results. To impart the required competencies in an efficient and sustainable way, preparative and accompanying measures of qualification have to be combined into a holistic concept adapted to the operator’s needs and the requirements of industrial application. By mutual amendment of fundamental training in coordinate metrology and continuous learning via a...
TC14 ISMQC 2007
· TC14
· 2007
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