On the selection of flatness measurement points in coordinate measuring machine inspection

2000 ◽  
Vol 40 (3) ◽  
pp. 427-443 ◽  
Author(s):  
Weon-Seok Kim ◽  
Shivakumar Raman
Keyword(s):  
Coordinate Measuring Machine ◽  
Measuring Machine ◽  
Flatness Measurement ◽  
Selection Of

scholarly journals Influence of the probing definition on the flatness measurement

2018 ◽  
Vol 9 ◽  
pp. 15 ◽  
Author(s):  
Djezouli Moulai-khatir ◽  
Eric Pairel ◽  
Hugues Favreliere
Keyword(s):  
Coordinate Measuring Machine ◽  
Minimum Volume ◽  
Analysis Study ◽  
Mechanical Parts ◽  
Minimum Zone ◽  
Cloud Points ◽  
Measuring Machine ◽  
Flatness Defect ◽  
Cloud Of Points ◽  
Flatness Measurement

The quality control of mechanical parts is generally performed on a coordinate measuring machine (CMM). The choice of the number of points to be sampled, their distributions and their positions on the surface, as well as the association criterion remains unresolved. This paper studies the variation of the flatness defect with regard to the number of palpated points. The methodology begins by sampling a cloud of points on a CMM. Then, a modal analysis study is carried out in order to generate a modal surfaces (digitally deformed). Insertion of the coordinate cloud points of these modal surfaces in the GEOVERIF software will allow estimation of the flatness defect. The results of the measured flatness by the three fitting criteria (minimum zone, least squares and minimum volume) are compared.

scholarly journals Robust Estimation of Optimal Sample Size for CMM Measurements with Statistical Tolerance Limits

2018 ◽  
Vol 220 ◽  
pp. 04001 ◽  
Author(s):  
Petr Chelishchev ◽  
Aleksandr Popov ◽  
Knut Sørby
Keyword(s):  
Sample Size ◽  
Cross Sections ◽  
Coordinate Measuring Machine ◽  
Cylindrical Part ◽  
Tolerance Limits ◽  
Optimal Sample ◽  
Free Model ◽  
Measuring Machine ◽  
Statistical Tolerance ◽  
Selection Of

The paper proposes the kernel probability density function approach to estimate the distribution of measurements on a part which is measured in a coordinate measuring machine (CMM). The study is based on the experimental data derived from internal cylinder measurements. The distribution free model suggested by Wilks was used as a reference for the selection of the sample size. Three cross sections of a cylinder were measured regarding to this reference. The work defines the minimum required sample size for obtaining at least 0.95 proportion of radius variation for particular studied cylindrical part with 95% confidence level.

scholarly journals Selection of the Best Model of Distribution of Measurement Points in Contact Coordinate Measurements of Free-Form Surfaces of Products

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5346 ◽  
Author(s):  
Marek Magdziak
Keyword(s):  
Coordinate Measuring Machine ◽  
New Method ◽  
Free Form ◽  
Experimental Investigations ◽  
Accuracy Of Measurements ◽  
Measuring Machine ◽  
Coordinate Measurements ◽  
Free Form Surface ◽  
Free Form Surfaces ◽  
Selection Of

The article presents a new method for determining the distribution of measurement points, which can be used in the case of contact coordinate measurements of curvilinear surfaces of products. The developed method is based on multi-criteria decision analysis. In the case of the new method, the selection of the distribution of measurement points on free-form surfaces is carried out based on the analysis of five different criteria. The selection of the best model of the distribution of measurement points results from the accuracy of coordinate measurements, the time needed to complete measurement tasks, the number of measurement points, the accuracy of the substitute surface representing the measured free-form surface and the area where measurement points are located. The purpose of using the developed method of the distribution of measurement points is to increase the performance of coordinate measurements primarily by increasing the automation of strategy planning of measurements of curvilinear surfaces and improving the accuracy of measurements of free-form surfaces of products. The new method takes into account various aspects of coordinate measurements to determine the final model of the distribution of measurement points on measured surfaces of products, thereby increasing the probability of the proper determination (i.e., identifying the highest deviations of a product) of the location of measurement points on the surfaces of a measured object. The paper presents an example of the application of the created method, which concerns the selection of the best model of the distribution of measurement points on a selected free-form surface. This example is based on, among others, the results of experimental investigations, which were carried out by using the ACCURA II coordinate measuring machine equipped with the VAST XXT measuring probe and the Calypso measurement software. The results of investigations indicate a significant reduction in time of coordinate measurements of products when using the new method for determining the distribution of measurement points. However, shortening the time of coordinate measurements does not reduce their accuracy.

Measurements of the Cape Astrometric Survey of the Southern Hemisphere

1978 ◽  
Vol 48 ◽  
pp. 515-521
Author(s):  
W. Nicholson
Keyword(s):  
Southern Hemisphere ◽  
Automatic Measuring ◽  
Measuring Machine ◽  
Final Selection ◽  
Selection Of

SummaryA routine has been developed for the processing of the 5820 plates of the survey. The plates are measured on the automatic measuring machine, GALAXY, and the measures are subsequently processed by computer, to edit and then refer them to the SAO catalogue. A start has been made on measuring the plates, but the final selection of stars to be made is still a matter for discussion.

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