Accuracy distribution and determination of the flexible three-coordinate measuring machine

2006 ◽  
Author(s):  
Chunhua Wang ◽  
Yetai Fei ◽  
Penghao Hu ◽  
Pingping Wang ◽  
Wentao Chen
Keyword(s):  
Coordinate Measuring Machine ◽  
Measuring Machine

Evaluation of Actual Geometric Tolerances Using Coordinate Measuring Machine Data

1989 ◽  
Author(s):  
W. H. ElMaraghy ◽  
Z. Wu ◽  
H. A. ElMaraghy
Keyword(s):  
Three Dimensional ◽  
Measurement Data ◽  
Simulated Data ◽  
Coordinate Measuring Machine ◽  
Optimization Techniques ◽  
Test Cases ◽  
Tolerance Zone ◽  
Geometric Tolerances ◽  
Measuring Machine

Abstract This paper focuses on the development of a procedure and algorithms for the systematic comparison of geometric variations of measured features with their specified geometric tolerances. To automate the inspection of mechanical parts, it is necessary to analyze the measurement data captured by coordinate measuring machines (CMM) in order to detect out-of-tolerance conditions. A procedure for determining the geometric tolerances from the measured three dimensional coordinates on the surface of a cylindrical feature is presented. This procedure follows the definitions of the geometric tolerances used in the current Standards, and is capable of determining the value of each geometric tolerance from the composite 3-D data. The developed algorithms adopt the minimum tolerance zone criterion. Nonlinear numerical optimization techniques are used to fit the data to the minimum tolerance zone. Two test cases are given in the paper which demonstrate the successful determination of geometric tolerances from given simulated data.

Methodology for evaluate the form deviations for formula one nose car

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Paul Bere ◽  
Calin Neamtu
Keyword(s):  
Composite Material ◽  
Laser Scanning ◽  
Coordinate Measuring Machine ◽  
3D Scanning ◽  
Cad Model ◽  
3D Laser Scanning ◽  
Formula One ◽  
Dimensional Deviation ◽  
Measuring Machine

AbstractThe paper presents a measuring strategy for a Formula One car using a Coordinate Measuring Machine (CMM) and a 3D laser scanning devices. The measurement procedures outlined the dimensional deviation of the CAD model and prototype made of composite material. The authors present two methods for the determination of symmetry for components of a Formula One car based on measuring and 3D scanning.

Reduce Positioning Error for Robot Manipulator with Intelligent Technique

2011 ◽  
Vol 403-408 ◽  
pp. 697-706
Author(s):  
Maryam Barati ◽  
Ahmad Reza Khoogar ◽  
Mehrzad Nasiriyan
Keyword(s):  
Robot Manipulator ◽  
Coordinate Measuring Machine ◽  
Least Square ◽  
Robot Kinematics ◽  
Automatic Calibration ◽  
Intelligent Technique ◽  
Measuring Machine ◽  
Three Degree Of Freedom ◽  
Kinematics Parameters

Using robot manipulators for high accuracy applications require precise value of the kinematics parameters. Since measurement of kinematics parameters are usually corrupted with errors and their accurate measurements are usually expensive, automatic calibration of robot link parameters makes the determination of kinematic parameters much simpler. In this paper a simple and easy to use algorithm is introduced for correction and calibration of robot kinematics parameters. Actually, at several end-effecter positions, the corresponding joint variables are measured simultaneously. This information is then used in three different algorithms; the Least Square (LS), the Particle Swarm Optimization (PSO) and the Genetic algorithms (GA) for automatic calibration and correction of the kinematics parameters. This process was also tested experimentally using a three degree of freedom manipulator which was actually built as a coordinate measuring machine (CMM). The experimental Results show that the intelligent algorithms provide better results for both parameter identification and calibration of the link parameters.

scholarly journals Assessment of Background Illumination Influence on Accuracy of Measurements Performed on Optical Coordinate Measuring Machine Equipped with Video Probe

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2509
Author(s):  
Wiktor Harmatys ◽  
Adam Gąska ◽  
Piotr Gąska ◽  
Maciej Gruza ◽  
Jerzy A. Sładek
Keyword(s):  
Coordinate Measuring Machine ◽  
Optical Systems ◽  
Diameter Measurement ◽  
Background Illumination ◽  
Multisensor Systems ◽  
Accuracy Of Measurements ◽  
Uncertainty Of Measurements ◽  
Measuring Machine ◽  
New Challenges

Currently the Coordinate Measuring Technique is facing new challenges both in terms of used methodology and a speed of measurement. More and more often modern optical systems or multisensor systems replace classic solutions. Measurement performed using the optical system is more vulnerable to incorrect points acquisition due to such factors as an inadequate focus or parameters of applied illumination. This article examines the effect of an increasing illumination on the measurement result. A glass reference plate with marked circles and a hole plate standard were used for the measurements performed on a multi-sensor machine Zeiss O’ Inspect 442. The experiment consisted of measurements of standard objects with different values of the backlight at the maximum magnification. Such approach allows to assess the influence of controlled parameter on errors of diameter and form measurements as well as an uncertainty of measurements by determination of ellipses of point repeatability. The analysis of the obtained results shows that increasing backlight mainly affects the result of the diameter measurement.

Determination of True Dimensional Quality and Build Errors Using Coordinate Measurement Data

1999 ◽  
Vol 121 (4) ◽  
pp. 749-755 ◽  
Author(s):  
R. J. Gu ◽  
G. C. Barber
Keyword(s):  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Coordinate Frame ◽  
Numerical Examples ◽  
Coordinate Measurement ◽  
Acceptable Quality ◽  
Measuring Machine ◽  
Material Points

For manufacturing personnel there exist two major tasks: determination of the quality of the build, and locating build errors if the quality is inferior. To serve this purpose a coordinate measuring machine is employed to determine the actual locations of designated material points. Depending on the measuring coordinate frame chosen, the initial raw data, unfortunately, do not impartially represent the true deviations of all the measurement points. This paper shows a technique to overcome this inevitable drawback embedded in the CMMs and determine if the build has acceptable quality under specified tolerances. Also presented in this paper is a method to quantify the quality of the measurement points for easy identification of build errors. Numerical examples are given to demonstrate the feasibility of the technique.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

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