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.

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.

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.

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.

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.

Theory and Algorithms for L1 Fitting Used for Planar Datum Establishment in Support of Tolerancing Standards

2013 ◽  
Author(s):  
Craig M. Shakarji ◽  
Vijay Srinivasan
Keyword(s):  
Convex Hull ◽  
Reference Frame ◽  
Point Contact ◽  
Coordinate Measuring Machine ◽  
Discrete Point ◽  
L1 Norm ◽  
Point Sampling ◽  
Measuring Machine ◽  
Coordinate Data

We present the theory and algorithms for establishing a datum plane consistent with ASME Y14.5 standard definitions. Such a datum plane will correspond to a planar datum feature sampled with coordinate data that is weighted. The method uses a one-sided minimization search based on the L1 (L1) norm. We prove that the problem reduces to a simple minimization search between the weighted centroid and the convex hull. The practice of unweighted fitting works well enough when point sampling is controlled and can thus be made uniform (e.g., using a discrete point contact Coordinate Measuring Machine). However, we show by example that nonuniformly sampled points (arising from many new measurement technologies) coupled with unweighted 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. Terse Mathematica code is included for the reader. The code is sufficient for constrained and unconstrained planar fitting as well as a 3-2-1 datum reference frame generation, which is also described in detail. We additionally prove convergence from the discrete to continuous cases of datum establishment as the point sampling becomes dense.

A coordinate measuring machine vision system

1999 ◽  
Vol 38 (3) ◽  
pp. 239-248 ◽  
Author(s):  
J.B. Liao ◽  
M.H. Wu ◽  
R.W. Baines
Keyword(s):  
Machine Vision ◽  
Vision System ◽  
Coordinate Measuring Machine ◽  
Machine Vision System ◽  
Measuring Machine

Accuracy Analysis of Machining Process Using a Spindle Probe and a CMM to Reduce the Scrap

2005 ◽  
Author(s):  
Yongjin Kwon
Keyword(s):  
Machine Tool ◽  
Measurement Data ◽  
Coordinate Measuring Machine ◽  
Machining Process ◽  
Inspection Time ◽  
Cnc Machine ◽  
Part Quality ◽  
Post Process ◽  
Measuring Machine ◽  
Touch Probe

In-process part inspection using a spindle touch probe has gained a significant importance, mainly because parts can remain on the machine without disrupting the machine setup while inspection is being conducted. This practice leads to a shorter inspection time, improved part accuracies, and reduction of scraps. Recently, intense domestic and international competition has put more importance on part quality in terms of producing parts right the first time and maintaining the consistent quality standards. A literature review revealed that a comparative analysis between in-process gauging using a touch probe and post-process inspection using a coordinate measuring machine (CMM) to ascertain part quality has not been adequately studied. Therefore, there is a need for a study to measure the characteristics of the two inspection techniques. To address the problem, cutting experiments were conducted and measurement data were analyzed using a state-of-the-art CNC machine, a CMM, a touch probe, and a high-precision ballbar system. The experimental data show that machined features and touch probe measurements are affected by the inherent shortcomings in machine tool structure, suggesting a machine tool capability analysis be undertaken in tune with the required tolerance specifications prior to machining operations, rather than solely relying on the touch probe inspection for part quality assessment.

CMM Dynamic Properties of the Scanning Measurement of a 2D Profile

2015 ◽  
Vol 9 (5) ◽  
pp. 530-533 ◽  
Author(s):  
Adam Woźniak ◽  
◽  
Grzegorz Krajewski
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Data Gathering ◽  
Coordinate Measuring Machine ◽  
Inspection Time ◽  
Coordinate Metrology ◽  
High Speed Data ◽  
Dynamic Errors ◽  
Measuring Machine ◽  
Modern Manufacturing

Scanning probe CMMs have come to be considered the standard in coordinate metrology, not only because they provide high-quantity, high-speed data gathering but also because the scanning technology significantly decreases inspection time. Modern manufacturing, especially in today’s highly competitive economy, requires increasingly efficient measuring machines and processes because inspection machines have often become the bottlenecks in the entire manufacturing processes. More efficient coordinate metrology can mean faster measurement cycles with acceptable accuracies. However, increasing scanning speeds has also significantly increased errors. This article proposes a new method of investigating and identifying the principal components of CMM dynamic errors. The principle of the method is presented, and the validity of the method is experimentally confirmed on a bridge coordinate measuring machine.

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