scholarly journals Digital Tolerence

2010 ◽  
Vol 132 (07) ◽  
pp. 32-34 ◽  
Author(s):  
Jean Thilmany
Keyword(s):  
Cultural Change ◽  
Computer Aided Design ◽  
Geometric Dimension ◽  
Coordinate Measuring Machine ◽  
Time To Market ◽  
Model Based ◽  
Inspection Process ◽  
Engineering Drawings ◽  
Measuring Machine ◽  
Aided Design

This article demonstrates the use of model-based definition (MBD), which can lead to improve productivity and reduce time-to-market. MBD is a method of annotating 3D computer-aided design models with geometric and tolerancing information. With Boeing moving to model-based definition, members of industry have approached the team in Montreal about investigating MBD’s usefulness. Experts believe that the MBD format, if widely adopted, would have implications for inspection. The part would be inspected against the tolerances contained within the CAD model rather than against the 2D engineering drawings, and that would speed the process and potentially make it even more accurate. The cultural change that will have to take place at most engineering companies will be difficult to tackle, and engineering and manufacturing managers know this. A model-based inspection software is being developed to read geometric, dimension, and tolerance information attached to a solid model. This will minimize operator input during development of coordinate measuring machine programs and improve the accuracy and integrity of the inspection process.

Automatic Coordinate Measuring Machine Inspection

1999 ◽  
Author(s):  
V. A. Albuquerque ◽  
F. W. Liou ◽  
S. Agarwal ◽  
O. R. Mitchell
Keyword(s):  
Path Planning ◽  
Computer Aided Design ◽  
Coordinate Measuring Machine ◽  
Industrial Applications ◽  
Prototype Development ◽  
Development Cycle ◽  
Inspection Process ◽  
Measuring Machine ◽  
Aided Design ◽  
Point Placement

Abstract In many industrial applications, such as product prototype development, automation of inspection process can greatly improve product quality and product development cycle, time. This paper discusses a development of a vision aided automatic inspection using Coordinate Measuring Machine (CMM). We seek to integrate the flexibility afforded by computer vision systems with the precision of numerically controlled coordinate measuring machines to achieve a fully automatic and reliable inspection of the industrial parts. The 3-D design information and part specification from computer-aided design file is used for inspection point placement and CMM path planning. The proposed system demonstrates that optimal collision-free inspection paths can be efficiently generated for geometrically complex parts consisting of multiply intersecting features. This is made possible by using iterative subdivision of surfaces for point placement coupled with, efficient 3-D collision avoidance and path planning. The paper discusses different algorithms used, and presents experimental results.

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.

The Integration of Coordinate Measuring Machines within a Design and Manufacturing Environment

1993 ◽  
Vol 207 (2) ◽  
pp. 91-98 ◽  
Author(s):  
A J Medland ◽  
G Mullineux ◽  
C Butler ◽  
B E Jones
Keyword(s):  
Computer Aided Design ◽  
Coordinate Measuring Machine ◽  
Research Programme ◽  
Standard Test ◽  
Feature Identification ◽  
Manufacturing Environment ◽  
Inspection Process ◽  
Engineering Environment ◽  
Measuring Machine ◽  
Probe Calibration

The role of the coordinate measuring machine within the inspection process has changed throughout its brief development. With its integration with industrial computer aided design (CAD) systems, its role is to change yet again. This paper presents the difficulties and limitations of current practice and identifies the inputs and decisions that need to be made within an integrated manufacturing environment. A research programme was undertaken to investigate an approach based upon intelligent communications between systems. This led to the creation of a demonstration system that was employed in the measurement of industrial components. A case study, using a standard test block, is included to illustrate the processes undertaken. This includes feature identification, probe calibration and selection strategies and automatic re-routing to minimize changes in probes and orientations. It is proposed that the approach demonstrated can be incorporated within a concurrent engineering environment to provide feedback and information about machine adjustments through a constraint modelling process.

Global Tangent Visibility Analysis for Polyhedral Computer Aided Design Models

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Zhi Yang ◽  
Richard A. Wysk ◽  
Sanjay Joshi
Keyword(s):  
Computer Aided Design ◽  
Coordinate Measuring Machine ◽  
Casting Process ◽  
Hot Wire ◽  
Visibility Analysis ◽  
Design Models ◽  
Visibility Algorithm ◽  
New Type ◽  
Measuring Machine ◽  
Aided Design

Visibility analysis is broadly used in milling and casting process planning and in coordinate measuring machine applications. However, standard visibility analysis (which involves determining visibility from a given viewpoint), cannot be applied directly to in-line cutting systems such as wire electrical discharge machines or hot wire foam cutters. The motivation of this paper is to accurately calculate the tangent visibility for objects represented by polygonal surfaces. In this paper we define a new type of visibility - tangent visibility. We develop an algorithm to calculate the global tangent visibility for in-line cutting systems, and several models are tested to verify its accuracy. Several polyhedral models are tested to verify the correctness of the tangent visibility algorithm; and the complexity of the algorithm is also discussed.

Towards Combining Digitization Techniques in the Generation of Reverse Engineering Data Sets

1999 ◽  
Author(s):  
C. J. Rolls ◽  
W. ElMaraghy ◽  
H. ElMaraghy
Keyword(s):  
Reverse Engineering ◽  
Computer Aided Design ◽  
Laser Scanning ◽  
Single Point ◽  
Laser Scanner ◽  
Coordinate Measuring Machine ◽  
Industrial Applications ◽  
Data Sets ◽  
Error Characterization ◽  
Measuring Machine

Abstract Reverse engineering (RE), may be defined as the process of generating computer aided design models (CAD) from existing or prototype parts. The process has been used for many years in industry. It has markedly increased in implementation in the past few years, primarily due to the introduction of rapid part digitization technologies. Current industrial applications include CAD model construction from artisan geometry, such as in automotive body styling, the generation of custom fits to human surfaces, and quality control. This paper summarizes the principles of operation behind many commercially available part digitization technologies, and discusses techniques involved in part digitization using a coordinate measuring machine (CMM) and laser scanner. An overall error characterization of the laser scanning digitization process is presented for a particular scanner. This is followed by a discussion of the merits and considerations involved in generating combined data sets with characteristics indicative of the design intent of specific part features. Issues in facilitating the assembly, or registration, of the different types of data into a single point set are discussed.

Constraint mechanisms for knowledge acquisition from computer-aided design data

1993 ◽  
Vol 7 (3) ◽  
pp. 181-188
Author(s):  
Harley R. Myler ◽  
Avelino J. Gonzalez ◽  
Massood Towhidnejad
Keyword(s):  
Process Control ◽  
Knowledge Acquisition ◽  
Computer Aided Design ◽  
Structural Information ◽  
Knowledge Bases ◽  
Knowledge Generation ◽  
Model Based ◽  
Reasoning System ◽  
Computer Aided ◽  
Aided Design

A number of automated reasoning systems find their basis in process control engineering. These programs are often model-based and use individual frames to represent component functionality. This representation scheme allows the process system to be dynamically monitored and controlled as the reasoning system need only simulate the behavior of the modeled system while comparing its behavior to real-time data. The knowledge acquisition task required for the construction of knowledge bases for these systems is formidable because of the necessity of accurately modeling hundreds of physical devices. We discuss a novel approach to the capture of this component knowledge entitled automated knowledge generation (AKG) that utilizes constraint mechanisms predicated on physical behavior of devices for the propagation of truth through the component model base. A basic objective has been to construct a complete knowledge base for a model-based reasoning system from information that resides in computer-aided design (CAD) databases. If CAD has been used in the design of a process control system, then structural information relating the components will be available and can be utilized for the knowledge acquisition function. Relaxation labeling is the constraint-satisfaction method used to resolve the functionality of the network of components. It is shown that the relaxation algorithm used is superior to simple translation schemes.

Associating 2D Sketch Information with 3D CAD Models for VR/AR Viewing During Bridge Maintenance Process

2019 ◽  
Vol 13 (4) ◽  
pp. 482-489 ◽  
Author(s):  
Fumiki Tanaka ◽  
Makoto Tsuchida ◽  
Masahiko Onosato ◽  
◽  
Keyword(s):  
Computer Aided Design ◽  
Mixed Reality ◽  
Industry Foundation Classes ◽  
3D Cad ◽  
Inspection Process ◽  
Cad Models ◽  
Maintenance And Inspection ◽  
Inspection Data ◽  
Aided Design ◽  
2D Sketches

Virtual reality (VR), augmented reality (AR), and mixed reality technologies are utilized at various stages of product lifecycle. For products with long lifecycles such as bridges and dams, the maintenance and inspection stages are very important to keep the product safe and well-functioning. One of the advantages of VR/AR is the ability to add important information such as past inspection data. Past inspection information is summarized in a document consisting of the 2D sketches of bridge degradation drawings. However, this degradation sketch is in 2D, and it has no correspondence with the 3D world. In this study, we propose a method to associate important information of 2D sketches with a 3D industry foundation classes (IFC) model, which is a standardized computer aided design model. To display a VR image of a bridge during the inspection process, the proposed method is applied to the 3D IFC model of the bridge and 2D degradation sketch of the inspection report.

Fixture Design Process Automation for Coordinate Measuring Machines: A Knowledge-Based Approach

2006 ◽  
Vol 526 ◽  
pp. 103-108
Author(s):  
J. Perez ◽  
R. Hunter ◽  
J.C. Hernandez ◽  
Antonio Vizan Idoipe
Keyword(s):  
Design Process ◽  
Manufacturing Process ◽  
Coordinate Measuring Machine ◽  
Fixture Design ◽  
Knowledge Based ◽  
Design And Manufacturing ◽  
Inspection Process ◽  
Measuring Machine ◽  
The Right ◽  
Inspection Fixture

Nowadays, the inspection process is an essential part of the manufacturing process, where a product is subjected to verification of the geometric features, dimensions and tolerance specifications with respect to the product design specifications. One of the most interesting topics in the automation of the inspection process is the right fixture design. In the fixture design process we have used the information provided by the part design and manufacturing process. However, the lack of integration and structuring of this information results in one of the most important problems, producing an increase in the time and cost implied in the development of the fixture design and its implementation. For this reason, this work presents a knowledge model for the inspection fixture design process for a Coordinate Measuring Machine (CMM), which allows the automation of the inspection fixture design process to be made easier, reducing time and cost associated to the inspection process and to the manufacturing process in general.

A Novel Method for Measuring Polyethylene Hip Liner Wear Using a Coordinate Measuring Machine and a Dual Stylus Probe

2016 ◽  
Vol 10 (1) ◽  
Author(s):  
Benjamin P. Cunkelman ◽  
Byoungwook Jang ◽  
Douglas W. Van Citters ◽  
John P. Collier
Keyword(s):  
Data Analysis ◽  
Data Acquisition ◽  
Computer Aided Design ◽  
Ex Vivo ◽  
Coordinate Measuring Machine ◽  
Linear Wear ◽  
Cad Model ◽  
Sources Of Error ◽  
Novel Method ◽  
Measuring Machine

Ex vivo high-resolution measurement of highly crosslinked (HXL) polyethylene hip liner wear is necessary to characterize the in vivo performance of these polymers that exhibit increased wear resistance. Current studies focus on using a coordinate measuring machine (CMM) to acquire data representing the bearing surface(s) of HXL hip liners and use this data to determine linear and volumetric wear. However, these current techniques are subject to error in both data acquisition and data analysis. The purpose of this study was to identify these sources of error and present a novel method for HXL wear measurement that minimizes these contributions to error: our novel methods use a CMM to measure both the articular and backside surfaces of HXL hip liners for subsequent data analysis in Geomagic Control and matlab. Our method involves a vertical orientation of the hip liner to enable one CMM scan of both sides of the hip liner. This method minimizes identified sources of error and proves to be an effective approach for data acquisition of HXL hip liner wear. We also find that our data analysis technique of calculating changes in wall thicknesses is effective in accounting for errors associated with data analysis. Validation of this technique occurred via measurement of two never-implanted HXL hip liners of different sizes (28 mm and 32 mm). In comparing the 32 mm hip liner to its corresponding computer-aided design (CAD) model, we found that our data acquisition technique led to a 0.0019 mm discrepancy between the scanned liner and its CAD model in measured thickness at the pole. We calculated 0.0588 mm and 0.0800 of linear wear for the 28 mm and 32 mm hip liners, respectively, based on our data analysis algorithm. We hypothesize that these reported linear wear values of the never-implanted hip liners are due to machining tolerances of the hip liners themselves.

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