Calculation of the parameters of a cylinder measured by a cross-section strategy on a coordinate measuring machine

2021 ◽  
Vol 26 (1) ◽  
pp. 14-22
Author(s):  
Ryszard Filipowski ◽  
Józef Zawora
Keyword(s):  
Computer Program ◽  
Least Squares ◽  
Cross Section ◽  
Coordinate Measuring Machine ◽  
Reference Plane ◽  
Cylinder Axis ◽  
Cad System ◽  
Measuring Machine ◽  
Auto Cad ◽  
Axis Passing

A computer program for calculating cylinder parameters was developed based on a measurement strategy of five circles arranged along the cylinder axis. The parameters calculated by the program are: cylinder diameter, axis of inclination of the cylinder axis to the reference plane, deviations from the least squares reference cylinder (LSCY), the axis passing through the centers of the outermost measurement circles. The graphics of deviation from the cylinder dimension is shown in the Auto CAD system using the script command. The developed program complements the CMM software.

Fitting Weighted Total Least-Squares Planes and Parallel Planes to Support Tolerancing Standards

2012 ◽  
Author(s):  
Craig M. Shakarji ◽  
Vijay Srinivasan
Keyword(s):  
Least Squares ◽  
Point Contact ◽  
Coordinate Measuring Machine ◽  
Total Least Squares ◽  
Point Sampling ◽  
Least Squares Fitting ◽  
Weighted Total Least Squares ◽  
Measuring Machine ◽  
Fitting In ◽  
Value Decomposition

We present elegant algorithms for fitting a plane, two parallel planes (corresponding to a slot or a slab) or many parallel planes in a total (orthogonal) least-squares sense to coordinate data that is weighted. Each of these problems is reduced to a simple 3×3 matrix eigenvalue/eigenvector problem or an equivalent singular value decomposition problem, which can be solved using reliable and readily available commercial software. These methods were numerically verified by comparing them with brute-force minimization searches. We demonstrate the need for such weighted total least-squares fitting in coordinate metrology to support new and emerging tolerancing standards, for instance, ISO 14405-1:2010. The widespread practice of unweighted fitting works well enough when point sampling is controlled and can be made uniform (e.g., using a discrete point contact Coordinate Measuring Machine). However, we demonstrate that nonuniformly sampled points (arising from many new measurement technologies) coupled with unweighted least-squares fitting can lead to erroneous results. When needed, the algorithms presented also solve the unweighted cases simply by assigning the value one to each weight. We additionally prove convergence from the discrete to continuous cases of least-squares fitting as the point sampling becomes dense.

scholarly journals Influence of Ablation on Differential Arc Resistance

2017 ◽  
Vol 4 (2) ◽  
pp. 145-148 ◽  
Author(s):  
L. S. J. Bort ◽  
V. Freiermuth ◽  
C. M. Franck
Keyword(s):  
Cross Section ◽  
Circuit Breaker ◽  
Coordinate Measuring Machine ◽  
Prior Work ◽  
Dry Air ◽  
Measuring Machine ◽  
The Cross

The influence of ablation on the du/di behavior of an arc in a model gas circuit breaker was examined. Specifically the transition from a state without ablation in the nozzle towards states with ablation was of interest, since prior work indicated that for high currents the voltage becomes constant or du/di gets even positive if ablation is present. Measurements with different blow pressures and rectangular DC currents of varying amplitude were compared, using PMMA-nozzles and dry air as blowing gas. Ablation was measured by weighing the nozzle, scanning the cross section, and using a coordinate measuring machine. The results agreed well, and confirmed that higher pressure shifts the du/di curve towards more favorable values.

scholarly journals Near-End of Treatment Panoramic Radiograph in the Assessment of Mesiodistal Root Angulation

2008 ◽  
Vol 78 (3) ◽  
pp. 475-481 ◽  
Author(s):  
Ann Marie Owens ◽  
Ama Johal
Keyword(s):  
Coordinate Measuring Machine ◽  
Panoramic Radiograph ◽  
Reference Plane ◽  
End Of Treatment ◽  
Variation Range ◽  
Measuring Machine ◽  
Clinically Significant ◽  
Set Up ◽  
Lower Arch ◽  
The Ideal

Abstract Objectives: To test the hypothesis that there is no difference between the actual mesiodistal root angulation and the mesiodistal root angulation as measured on the panoramic radiograph. Materials and Methods: A typodont dentition was set up into a Class I occlusion. Wire struts were placed on the buccal surface of each tooth to represent their long axes. The dentition was fixed into a natural skull for imaging. The radiographic and true mesiodistal angulation of each tooth to a horizontal reference plane (the arch wire) was measured using a coordinate measuring machine (CMM). The mesiodistal root positions were then altered to a more mesial and then more distal position and the measurements were repeated. Results: Only 26.7% of the radiographic root angulations were within the clinically acceptable angular variation range of ±2.5°. The greatest variation in the upper arch occurred in the canine-premolar area where the roots were projected as being more divergent. The greatest variation in the lower arch occurred in the lateral incisor-canine region where these roots were projected as being more convergent. The extent of radiographic distortion is statistically greater in the lower arch than in the upper arch in the ideal (P ≤ .05) and distal (P ≤ .01) root positions. Conclusions: The hypothesis is rejected. There is a clinically significant variation between the radiographic and the true root angulations recorded. Caution is advised when interpreting mesiodistal root angulation using this radiograph.

The Use of a Machine Vision System in a Flexible Manufacturing Cell Incorporating an Automated Coordinate Measuring Machine

1993 ◽  
Vol 207 (3) ◽  
pp. 199-204 ◽  
Author(s):  
X J Wang ◽  
C Butler
Keyword(s):  
Machine Vision ◽  
Flexible Manufacturing ◽  
Computer Aided Design ◽  
Manufacturing System ◽  
Vision System ◽  
Coordinate Measuring Machine ◽  
Cad System ◽  
Measuring Machine ◽  
Processing Techniques ◽  
Aided Design

The aim of this paper is to present a practical approach to the solution of problems associated with using an automated coordinate measuring machine (CMM) in a flexible manufacturing system (FMS) environment. The approach described uses machine vision and image processing techniques to permit transformations of the coordinate systems. In order to achieve flexible inspection, the system can recognize different workpieces by a quick matching method. The actual measuring path for the workpiece is derived from the original measuring path templates to allow for a workpiece to be measured in an arbitrary orientation on the table of the CMM. The original measuring path can be generated off-line by self-teach programming or from a computer aided design (CAD) system. The generation of the actual measuring path of the CMM is not limited by the complexity of the original off-line measuring path.

Integrated Environment for PDM, RE and CAD/ CAM System

2011 ◽  
Vol 130-134 ◽  
pp. 491-494 ◽  
Author(s):  
Yi Fei Tong ◽  
Yi Chun Yang ◽  
Hao Tian ◽  
Dong Bo Li
Keyword(s):  
Functional Model ◽  
Coordinate Measuring Machine ◽  
Original Data ◽  
Geometric Information ◽  
Engineering Software ◽  
Cad System ◽  
Integrated Environment ◽  
Reconstructed Surfaces ◽  
Cad Cam ◽  
Measuring Machine

Functional model for realizing the data integration of product data management, reverse engineering software and CAD/CAM system is proposed to support digitized prototyping and shorten the time market of new product. Measured data from CMM (Coordinate Measuring Machine), describing the geometric information of product would be sent directly to RE software. After refining and smoothing the “data cloud”, meshes of curves would be generated and sent to CAD/CAM system. The original data will be overlaid onto NURBS model obtained from CAD system to verify the reconstructed surfaces. The CAD model may be further faired, analyzed or NC machined within the context of current CAD/CAM system. Feasibility of such an approach has been testified on a sample part.

Integration of Multi-View Data Based on Auxiliary Reference Plane

2010 ◽  
Vol 139-141 ◽  
pp. 1361-1364
Author(s):  
Ke Wei Lin ◽  
Xin Liu ◽  
Ming De Duan
Keyword(s):  
Reverse Engineering ◽  
Coordinate Measuring Machine ◽  
Complex Surface ◽  
Reference Plane ◽  
Scanning System ◽  
Practical Result ◽  
Laser Tracking ◽  
System A ◽  
Measuring Devices ◽  
Measuring Machine

The integration of multi-view data in the acquisition of complex surface is researched by using the CMM (coordinate measuring machine) and the laser tracking scanning system. A multi-view data integration method based on the auxiliary reference plane is presented. With the precise auxiliary reference plane, the data measured by the different measuring devices and measuring views are aligned and the accuracy is analyzed. If the error is controlled in a certain range, this method can satisfy the demands of the model and assembly. The problems of low-efficient and low-accuracy in the data fusion of complex surface during the reverse engineering are solved. Meanwhile, the advantages of the different measuring devices and measuring methods are developed. This method has been applied to the reverse engineering development for a motorcycle cover model. The practical result shows that this new method is feasible and efficient.

Reverse Engineering Approach for Object with Free-Form Surfaces Using Standard Surface-Solid Parametric CAD System

2009 ◽  
Vol 147-149 ◽  
pp. 706-711 ◽  
Author(s):  
Andrzej Łukaszewicz ◽  
Kanstantsin Miatliuk
Keyword(s):  
Coordinate Measuring Machine ◽  
Free Form ◽  
Cad System ◽  
Solid Models ◽  
Middle Range ◽  
Feature Based ◽  
Measuring Machine ◽  
Cloud Of Points ◽  
Free Form Surfaces ◽  
Modelling Process

In this paper the reverse modelling process for mapping and reconstructing the geometric characteristics of element with free-form surfaces as virtual CAD model is described. The basic approach in reverse modelling process in middle range standard parametric 3D modeler such as SolidWorks system is presented. The digitizing process was performed on the coordinate measuring machine. Using surface-solid modelling tools the virtual solid models were created. They are based on prepareing 3D curves from cloud of points as a sectional profiles. As the next step, it is possible to realize various CAx applications based on 3D feature-based model. In our case an abrasive wear of rotor blade was estimated.

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