Slicing: A Procedure for Tolerance Evaluation of Manufactured Parts Using CMM Measurement Data

1995 ◽  
Author(s):  
Yu Wang ◽  
Shilendra Gupta ◽  
Srinavas Rao
Keyword(s):  
Computational Complexity ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Significant Loss ◽  
Processing Procedure ◽  
Machined Parts ◽  
Measuring Machine ◽  
Part Model

Abstract This paper presents a sampling and processing procedure for tolerance evaluation of machined parts. In this method, deviations of the measured points from their ideal feature surface are evaluated in the plane where the data is measured by a Coordinate Measuring Machine (CMM). This procedure is called slicing. It is shown that the use of the structure inherent in measurement data has a potential in reducing computational complexity for evaluation of certain types of form tolerances without significant loss of accuracy. An application of the proposed method to the development of manufactured part model for automotive spaceframe structures is also discussed.

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.

scholarly journals A “Double Accuracy Theory” and Experimental Research on Precision Grinding

2020 ◽  
Vol 10 (6) ◽  
pp. 2030
Author(s):  
Lai Hu ◽  
Yipeng Li ◽  
Jun Zha ◽  
Yaolong Chen
Keyword(s):  
High Speed ◽  
Coordinate Measuring Machine ◽  
Precision Grinding ◽  
Machined Parts ◽  
Accuracy Theory ◽  
Machine Theory ◽  
Ultra Precision ◽  
Measuring Machine ◽  
Grinding Machine ◽  
Multi Body

In the global machining industry, ultra-precision/ultra-high-speed machining has become a challenge, and its requirements are getting higher and higher. The challenge of precision grinding lies in the difficulty in ensuring the various dimensions and geometric accuracy of the final machined parts. This paper mainly uses the theory of a multi-body system to propose a “double accuracy” theory of manufacturing and measurement. Firstly, the grinding theory with an accuracy of 0.1 μm and the precision three-coordinate measuring machine theory with an accuracy of 0.3 μm are deduced. Secondly, the two theories are analyzed. Aiming to better explain the practicability of the “double accuracy” theory, a batch of motorized spindle parts is processed by a grinding machine. Then the precision three-coordinate measuring machine is used to measure the shape and position tolerances such as the roundness, the squareness, the flatness, and the coaxiality. The results show that the reached roundness of part A and B is 5 μm and 0.5 μm, the squareness is 3 μm and 4.5 μm, and the coaxiality tolerance is 1.2 μm, respectively.

Autonomously Generative CMM Part Programming for In-Process Inspection

2003 ◽  
Vol 125 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Jiancheng Liu ◽  
Hung Ng ◽  
Kazuo Yamazaki ◽  
Kazuo Nakanishi
Keyword(s):  
Coordinate Measuring Machine ◽  
Programming Approach ◽  
Programming System ◽  
Programming Methodology ◽  
Process Measurement ◽  
Complex Part ◽  
Measuring Machine ◽  
Programming Process ◽  
Machining Operations ◽  
Part Model

This paper presents an in-process inspection-oriented autonomously generative CMM (Coordinate Measuring Machine) part programming methodology with a simplified part programming process to decrease the time and skill for CMM part programming. The proposed method differs from the CAD-based CMM programming approach. Using this new method, machining features in a complex part can be efficiently inspected after any stage of machining operations or after machining these features. The concept of the proposed CMM part programming approach and its implementation are described in this paper. The results obtained from the feasibility study show the developed CMM part programming system can autonomously generate an inspection plan for a work-in-progress part model generated from NC programs to realize the in-process measurement.

A study on the key techniques of application of REVO five-axis system in non-orthogonal coordinate measuring machine

2016 ◽  
Vol 231 (4) ◽  
pp. 730-736 ◽  
Author(s):  
Haitao Zhang ◽  
Shugui Liu ◽  
Xinghua Li
Keyword(s):  
Mathematical Model ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Coordinate Measuring Machines ◽  
Measurement Results ◽  
Measuring Machine ◽  
Key Techniques ◽  
Five Axis ◽  
The Mathematical Model ◽  
Body Theory

REVO five-axis system, designed for the orthogonal coordinate measuring machines, must be reconfigured for the application in the non-orthogonal coordinate measuring machines. First, in this article, error sources of the system and components of measurement data are analyzed; then, scale values of coordinate measuring machine axes, which are essential to derive the coordinates of measured points in non-orthogonal coordinate measuring machine, are separated out. Besides, the mathematical model of REVO is established based on the quasi-rigid body theory, from which the measurement results can be evaluated by data derived instead of that returned by the system. The effectiveness of both separation of scale values and mathematical model of REVO is proved by experiments and practice. The research of this article is of great significance to the application of REVO five-axis system in the non-orthogonal coordinate measuring machine.

Reconstructing of Prototype Surface with Reverse Engineering and Data Process Technology

2010 ◽  
Vol 458 ◽  
pp. 368-373 ◽  
Author(s):  
Dong Man Yu ◽  
Xiao Jing Li ◽  
Yi Xiong ◽  
Zhi Hua Gao ◽  
D. Wang
Keyword(s):  
Reverse Engineering ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Physical Object ◽  
Engineering System ◽  
Complex Data ◽  
Process Technology ◽  
Noise Elimination ◽  
Data Process ◽  
Measuring Machine

Design and manufacture of pioneer products with lower cost and shorter cycle is a major mission for an enterprise, and reverse engineering (RE) plays an important role in accelerating product research and borrowing ideals from other business. However, due to special structure and complex topology relation, obtaining full surface data of a prototype is not an easy thing and should carry out complex data process procedure to get global model. This paper describes the origin point cloud acquisition method and the data processing steps for better point quality. Based on reverse engineering system of a toy prototype, a fine surface reconstruction module is developed. Measurement data are acquired by scanning the physical object using three-dimensional coordinate measuring machine (CMM) and an optical scanning device. The model establishment and data process of the prototype, such as noise elimination, data interpolation, data smoothing, data filtering, data splicing and surface reconstructing are conducted subsequently. Through processing of measurement data, the authors succeed in creating a CAD model of the prototype and gaining a good result.

scholarly journals ROBUST ENGINEERING CASE STUDY FOR SIMULTANEOUS PARAMETER OPTIMIZATION OF A DEEP DRILLING PROCESS

2017 ◽  
Vol 45 (1) ◽  
pp. 27
Author(s):  
Laurentiu A Mihail
Keyword(s):  
High Speed ◽  
Coordinate Measuring Machine ◽  
Drilling Process ◽  
Deep Drilling ◽  
Flexible System ◽  
Machined Parts ◽  
Measuring Machine ◽  
Peck Drilling

The paper reflects de overall results of an experiment developed for optimising a deep peck drilling process, using an extra-long flute drill. The problem stated was the dimensional, geometrical and orientation accuracy of the holes machined by the previously mentioned machining method. The target was to improve the quality of the machined parts and to reach the maximum productivity in the same time. The optimisation method used was the Taguchi Method, with a L423 fractionated factorial array. Another important issue was to optimise several quality characteristics, simultaneously. After machining the test part on a high-speed machining flexible system, the parts were measured on a coordinate measuring machine. Finally, the data was computed assisted by an advanced quality software. The simultaneous optimisation was achieved by validated method, through several iterations based on advanced process and design of experiments knowledge. Finally, the conclusions were compared with another results, from the same research program, validating it.

Best Fit Uncertainty Analysis for Computing Geometric Tolerances

1997 ◽  
Author(s):  
Hong-Tzong Yau
Keyword(s):  
Sample Size ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Point Location ◽  
Geometric Tolerances ◽  
Surface Deviation ◽  
Measuring Machine ◽  
Point Data ◽  
Geometric Variables ◽  
Best Fit

Abstract In computing geometric tolerances using point data from a coordinate measuring machine (CMM), a best fit process needs to be carried out to bring the measurement data to the coordinate system of the substitute geometry. The measurement data does not precisely conform to the substitute geometry. It involves errors from machining as well as measurement itself. With this error-carrying measurement data, the best fit result contains uncertainties which in turn reduce the accuracy of the evaluated tolerances. In this paper, a model is proposed to estimate the best fit uncertainties caused by surface deviation, point location, and CMM sample size. The model was verified by simulation and experiment. To explore factors that affect the uncertainty variations, geometric variables that influence the uncertainties were first studied. Then, to understand the effect of point location on the uncertainty, optimization using the conjugate gradient method was developed to find the best measurement locations by minimizing the total uncertainties. In addition, simulations showed that the uncertainty is inversely proportional to the squared root of the number of points. This result can be used to predict the CMM sample size that will control the best fit uncertainty under certain tolerances.

scholarly journals Determination of Directional Residual Stresses by the Contour Method

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1104 ◽  
Author(s):  
Josef Hodek ◽  
Antonín Prantl ◽  
Jan Džugan ◽  
Pavel Strunz
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Electrical Discharge Machine ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Material Model ◽  
Element Model ◽  
Contour Method ◽  
Diffraction Measurement ◽  
Measuring Machine

This study evaluated residual stresses in heat-treated specimens made of 316L stainless steel using FE analysis and compared them with stresses determined by the contour method. Contour method is usually used just for evaluation of residual stresses that are normal to the cut plan. In the current study this approach is extended and both normal and tangential stresses are determined. The specimens were cut using wire electrical discharge machine and the contours of the cut were measured using a coordinate measuring machine. The prior treatment of the specimens was simulated using the finite-element method. An appropriate boundary condition and temperature-dependent material model were employed. The finite-element model was validated against neutron-diffraction measurement data. The results showed a good agreement in normal and tangential directions of stress.

scholarly journals Traceability on Machine Tool Metrology: A Review

2017 ◽  
Author(s):  
Unai Mutilba ◽  
Eneko Gomez-Acedo ◽  
Gorka Kortaberria ◽  
Aitor Olarra ◽  
José Antonio Yagüe-Fabra
Keyword(s):  
Machine Tool ◽  
Manufacturing Process ◽  
Machine Tools ◽  
Nuclear Power ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Manufacturing Processes ◽  
Scientific Objective ◽  
Measuring Process ◽  
Measuring Machine

Errors during manufacture of high value components are not acceptable nowadays in driving industries such as energy and transportation. Sectors such as aerospace, automotive, shipbuilding, nuclear power, large science facilities or wind power manufacture complex and accurate components that demand close measurements and fast feedback into manufacturing processes. New measuring technologies are already available in machine tools, including integrated touch probes and fast interface capabilities. They shall provide the possibility to measure the workpiece during or after the manufacturing process, maintaining the original setup of the workpiece and avoiding the manufacturing process from being interrupted to transport the workpiece to a measuring position. However, the traceability of the measurement process on a machine tool is not ensured yet and measurement data is still not fully reliable for process control or product validation. Due to the similarity between a coordinate measuring machine and a machine tool, some of the methods applied for a correct assessment of uncertainty in coordinate measuring machines are adapted to the challenges of a machine tool. The scientific objective is to determine the uncertainty on a machine tool measurement and, in this way, convert it into a machine integrated traceable measuring process. This paper reviews the fundamentals of machine tool metrology.

Integrating a Vision System With a Coordinate Measuring Machine to Automate the Datum Alignment Process

2005 ◽  
Author(s):  
Rajesh Subramanian ◽  
H. James de St. Germain ◽  
Samuel Drake
Keyword(s):  
Reference Frame ◽  
Vision System ◽  
Coordinate Measuring Machine ◽  
Inspection Time ◽  
Alignment Procedure ◽  
Machined Parts ◽  
Alignment Technique ◽  
Alignment Process ◽  
Measuring Machine ◽  
Part Fixturing

Inspection is an important stage in the manufacturing process of machined parts. Coordinate measuring machines (CMM) have become more automatic, programmable, and capable of fulfilling the growing demands of inspection. However, fixturing (datum alignment) of parts is still done manually, consuming valuable inspection time. In this paper, we describe an automated datum alignment technique which integrates a vision system with the CMM to avoid part fixturing. The rough position of the part is estimated through image analysis. This initial reference frame drives the CMM through an automatic datum alignment procedure, thereby automatically establishing the reference frame without the use of fixtures. This technique has been demonstrated for two and a half dimensional (2.5D) machined parts with well-defined features that exhibit a stable position on a flat table.

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