Form Assessment in Coordinate Metrology

2010 ◽  
pp. 69-90 ◽  
Author(s):  
Alistair B. Forbes ◽  
Hoang D. Minh
Keyword(s):  
Coordinate Metrology

Evaluation of Deviation Zone Based on Maximum Conformance to Tolerances

2011 ◽  
Author(s):  
Ahmad Barari
Keyword(s):  
Closed Loop ◽  
Evaluation Process ◽  
Accurate Estimation ◽  
Tolerance Zone ◽  
Coordinate Metrology ◽  
Inspection Process ◽  
Geometric Deviations ◽  
The Given ◽  
Best Fit ◽  
Deviation Zone

The accurate estimation of the geometric deviations is not possible only by manipulating the Euclidian distances of the discrete measured points from substitute geometry. The real geometric deviations of a measured surface need to be calculated based on the desired tolerance zone of the surface. This fact is usually neglected in common practices in the coordinate metrology of surfaces. The importance of considering the desired tolerance zone in estimation of the optimum deviation zone is demonstrated in this paper. Then a best fit method is presented which complies with the tolerance requirements of the designed surface. The developed fitting methodology constructs a substitute geometry to minimizes the residual deviations corresponding to the given tolerance zone and the needs of down-stream operations that use the results of the inspection process. It is shown how the developed objective function can be adopted for a case of closed-loop manufacturing process, when the under-cut residual deviations of the manufactured part can be corrected by a down-stream operation. In order to validate the proposed methodology, experiments are conducted. The results show a significant reduction of uncertainties in coordinate metrology of geometric surfaces. Implementation of this method directly results in increasing the accuracy of the entire tolerance evaluation process, and less uncertainty in quality control of the manufactured parts.

Evaluation Method for Geometrical Forms in Coordinate Metrology

1993 ◽  
pp. 711-716 ◽  
Author(s):  
Pavel G. Ikonomov ◽  
Fumiki Tanaka ◽  
Takeshi ICishinamia ◽  
Hideaki Okamoto ◽  
Toyoharu Sasaki
Keyword(s):  
Evaluation Method ◽  
Coordinate Metrology

scholarly journals Industrial Calibration Procedure for Confocal Microscopes

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4137 ◽  
Author(s):  
Alberto Mínguez Martínez ◽  
Jesús de Vicente y Oliva
Keyword(s):  
Reference Material ◽  
Research And Development ◽  
Calibration Procedure ◽  
Submillimeter Range ◽  
Optical Instruments ◽  
Coordinate Metrology ◽  
Dimensional Measurements ◽  
Focus Variation ◽  
Key Aspects ◽  
Calibration Laboratories

Coordinate metrology techniques are widely used in industry to carry out dimensional measurements. For applications involving measurements in the submillimeter range, the use of optical, non-contact instruments with suitable traceability is usually advisable. One of the most used instruments to perform measurements of this type is the confocal microscope. In this paper, the authors present a complete calibration procedure for confocal microscopes designed to be implemented preferably in workshops or industrial environments rather than in research and development departments. Therefore, it has been designed to be as simple as possible. The procedure was designed without forgetting any of the key aspects that need to be taken into account and is based on classical reference material standards. These standards can be easily found in industrial dimensional laboratories and easily calibrated in accredited calibration laboratories. The procedure described in this paper can be easily adapted to calibrate other optical instruments (e.g., focus variation microscopes) that perform 3D dimensional measurements in the submillimeter range.

Measurement Uncertainty Limit of a Video Probe in Coordinate Metrology

CIRP Annals ◽  
1996 ◽  
Vol 45 (1) ◽  
pp. 493-496 ◽  
Author(s):  
Seung-Woo Kim ◽  
P.A. McKeown
Keyword(s):  
Measurement Uncertainty ◽  
Coordinate Metrology

A Comparison of Virtual Condition Cylinder Evaluation Methods in Coordinate Metrology

2008 ◽  
Author(s):  
Steven Turek ◽  
Sam Anand
Keyword(s):  
Sample Size ◽  
Geometric Analysis ◽  
Sampled Data ◽  
Material Condition ◽  
Novel Approach ◽  
Real World Applications ◽  
Coordinate Metrology ◽  
Normal Method ◽  
Geometric Relationship

When a cylindrical datum feature is specified at maximum material condition (MMC) or least material condition (LMC) a unique circumstance arises: a virtual condition (VC) cylindrical boundary must be defined [1]. The geometric relationship between a cylindrical point cloud obtained from inspection equipment and a VC cylinder has not been specifically addressed in previous research. In this research, novel approaches to this geometric analysis are presented, analyzed, and validated. Two of the proposed methods are new interpretations of established methods applied to this unique geometric circumstance: least squares and the maximum inscribing cylinder (MIC) or minimum circumscribing cylinder (MCC). The third method, the Hull Normal method, is a novel approach specifically developed to address the VC cylinder problem. Each of the proposed methods utilizes a different amount of sampled data, leading to various levels of sensitivity to sample size and error. The three methods were applied to different cylindrical forms, utilizing various sampling techniques and sample sizes. Trends across sample size were analyzed to assess the variation in axial orientation when compared to the true geometric form, and a relevant case study explores the applicability of these methods in real world applications.

The analysis of feature-based measurement error in coordinate metrology

2004 ◽  
Vol 36 (3) ◽  
pp. 237-251 ◽  
Author(s):  
WENZHEN HUANG ◽  
ZHENYU KONG ◽  
DARIUSZ CEGLAREK ◽  
EMILIO BRAHMST
Keyword(s):  
Measurement Error ◽  
Coordinate Metrology ◽  
Feature Based

Point Cloud to CAD Model Registration Methods in Manufacturing Inspection

2006 ◽  
Vol 6 (4) ◽  
pp. 418-421 ◽  
Author(s):  
Thomas M. Tucker ◽  
Thomas R. Kurfess
Keyword(s):  
Computer Vision ◽  
Virtual World ◽  
Point Cloud ◽  
Physical World ◽  
Coordinate Frame ◽  
Cad Model ◽  
Modern Computer ◽  
Coordinate Metrology ◽  
Flow Of Information

Modern computer vision and coordinate metrology systems provide an ever-increasing flow of information from the physical world we live in to the virtual world inside computer systems. Often the coordinate system of the metrology device has a different coordinate frame from that of the existing objects in the virtual world. To rectify these differences, a process called registration is often applied. This paper uses a case study to highlight the differences between various registration techniques.

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