Measurement uncertainty assessment of Coordinate Measuring Machines by simulation and planned experimentation

2011 ◽  
Vol 4 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Francesco Aggogeri ◽  
Giulio Barbato ◽  
Emanuele Modesto Barini ◽  
Gianfranco Genta ◽  
Raffaello Levi
2012 ◽  
Vol 220-223 ◽  
pp. 875-879
Author(s):  
Ying Xu ◽  
Cun Yin ◽  
Zheng Hai Long

In order to better simulate the flowing condition of wet gas, Tianjin University has designed and built up a wet gas flow experimental facility with adjustable and intermediate pressure in the flow laboratory. The designed pressure of the facility which used standard meter method and dual closed-loop design is 4MPa. The experiment medium is air and water, and the highest operation pressure is 1.6MPa. The gas flow rate range is 3~1000m3/h, and the liquid flow rate range is 0.05~8 m3/h. This article includes the structure introduction of the facility and the calculation of pressure loss of the system, etc. By the uncertainty assessment for the discussed facility, the conclusion is stated that the facility’s gas measurement uncertainty is 1% and the facility’s liquid measurement uncertainty is 0.35%.


2018 ◽  
Vol 7 (2) ◽  
pp. 609-620 ◽  
Author(s):  
Dmytro Sumin ◽  
Rainer Tutsch

Abstract. We suggest a procedure for the correction of the errors caused by thermal expansion of a workpiece and the scale of a linear measuring instrument (coordinate measuring machines, length measuring machines, etc.) when linear measurements are performed at nonstandard temperature. We use a calibrated reference workpiece but do not require temperature measurements. An estimation of the measurement uncertainty and application examples are given.


Author(s):  
Mélanie Delort ◽  
Damien Ali Hamada FAKRA ◽  
Bruno Mallet-Damour ◽  
Jean Claude Gatina

Abstract Studying thermo-optical (i.e., thermal conductivity, optical re ectance, optical transmittance, and optical absorbance) properties of construction materials is essential for improving human comfort within a building. Typically, these properties are measured independently using specific equipment. The emerging of new innovative construction structures, such as translucent materials, makes the experimental characterization of these properties more challenging to observe. Recently, a new device, called MultiCoefMeter (McM), which rapidly and simultaneously measures all these properties, has been created. The study described in this article covers the calculation technique for estimating measurement uncertainties linked to morphology, the component parts, and the physical formula of the experimental apparatus. The measurement uncertainty estimates are obtained from knowledge of the color of the system's walls, placement, and form of the McM components, placement of measurement sensors, and the application of measurement collection equipment. Therefore, a thorough calculation analysis was performed on the sub-systems. Calculations are divided between two categories: those based on mathematical tools and information given by the makers, and those based on experimental observations obtained during reliability testing. These uncertainties originate from statistical tools, geometric tolerance of the system, comparison with standards, and the error propagation laws of the physical models link with the device. All these uncertainties were summed up and given a global value, no more than 5%, conforming to the ASTM standard (E1225). Finally, a general method to quantify measurement uncertainty value of any experimental device was proposed.


2018 ◽  
Vol 9 (1) ◽  
pp. 6 ◽  
Author(s):  
Yinbao Cheng ◽  
Zhongyu Wang ◽  
Xiaohuai Chen ◽  
Yaru Li ◽  
Hongyang Li ◽  
...  

Measuring instruments are intended to be intelligent, precise, multi-functional and developing multidirectionally, scientific, and reasonable; the reliable evaluation of measurement uncertainty of precision instruments is also becoming more and more difficult, and the evaluation of the Coordinate Measuring Machines (CMM) measurement uncertainty is among the typical problems. Based on Geometric Product Specification (GPS), this paper has systematically studied the CMM uncertainty for evaluating the size and geometrical errors oriented toward measurement tasks, and thus has realized the rapid and reliable evaluation of the CMM uncertainty for task-oriented measurement. For overestimation of the CMM uncertainty for task-oriented measurements in the initial evaluation, a systematic optimization solution has been proposed. Finally, the feasibility and validity of the evaluation model and the optimization method have been verified by three different types of measurement examples of diameter, flatness and perpendicularity. It is typical and representative to systematically solve the problem of the CMM uncertainty for evaluating the measurement tasks targeted at dimensions and geometric errors, and the research contents can be effectively applied to solve the uncertainty evaluation problems of other precision instruments, which are of great practical significance not only for promoting the combination of modern uncertainty theory and practical applications but also for improving the application values of precision measurement instruments.


2016 ◽  
Vol 106 (11-12) ◽  
pp. 782-786
Author(s):  
M. Ohlenforst ◽  
P. Dahlem ◽  
M. Peterek ◽  
R. Prof. Schmitt

Geometriemessungen auf Werkzeugmaschinen sind immer häufiger gefragt. Insbesondere bei der Großbauteileproduktion bieten sie ein hohes Potential, um Kosten und Zeit zu sparen. Anders als Koordinatenmessgeräte sind Werkzeugmaschinen rauen Umgebungsbedingungen von Produktionshallen ausgesetzt, welche die Messungen deutlich beeinflussen können. Der Fachbericht befasst sich mit einem Vorgehen, um umweltbedingte Störeinflüsse und die damit induzierten Messunsicherheiten zu bestimmen und zu reduzieren.   Geometric measurements on machine tools are getting more and more important for the production of large parts due to the big cost and time saving potential. Unlike coordinate measuring machines, machine tools are exposed to rough shop floor conditions generating large measurement uncertainties. The article describes a procedure to define and reduce these disturbances and the specific measurement uncertainties.


Author(s):  
Soichi Ibaraki ◽  
Yoshihiro Kimura ◽  
Yu Nagai ◽  
Shizuo Nishikawa

For on-machine measurement of workpiece position, orientation, and geometry on machine tools, five-axis continuous (scanning) measurement by using a laser displacement sensor has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-triggered contact probe. In any on-machine measurement schemes, major contributors to their measurement uncertainty are error motions of the machine tool itself. This paper formulates the influence of geometric errors of rotary axis average lines on the measurement uncertainty of the five-axis on-machine measurement by using a laser displacement sensor. To validate the present simulator, experimental comparison of measured and simulated trajectories is conducted on five-axis on-machine measurement of a precision sphere of the precalibrated geometry. For total 28 paths measured on the spherical surface, an error in the simulated trajectories from measured trajectories (properly low-pass filtered) was at maximum 5 μm. Uncertainty assessment demonstration for more practical application example of a turbine blade measurement is also presented.


2018 ◽  
Vol 101 (4) ◽  
pp. 1205-1211
Author(s):  
Saad Alaoui Sossé ◽  
Taoufiq Saffaj ◽  
Bouchaib Ihssane

Abstract Recently, a novel and effective statistical tool called the uncertainty profile has been developed with the purpose of graphically assessing the validity and estimating the measurement uncertainty of analytical procedures. One way to construct the uncertainty profile is to compute the β-content, γ-confidence tolerance interval. In this study, we propose a tolerance interval based on the combination of the generalized pivotal quantity procedure and Monte-Carlo simulation. The uncertainty profile has been applied successfully in several fields. However, in order to further confirm its universality, this newer approach has been applied to assess the performance of an alternative procedure versus a reference procedure for counting of Escherichia coli bacteria in drinking water. Hence, the aims of this research were to expose how the uncertainty profile can be powerfully applied pursuant to ISO 16140 standards in the frame of interlaboratory study and how to easily make a decision concerning the validity of the procedure. The analysis of the results shows that after the introduction of a correction factor, the alternative procedure is deemed valid over the studied range because the uncertainty limits lie within the acceptability limits set at ±−0.3 log unit/100 ml for a β = 66.7% and γ = 90%.


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