Intelligent integration of computer aided inspection with CAD/CAM systems

Liebar, A.M., 1993. Intelligent integration of computer aided inspection with CAD/CAM systems. MPhil, Nottingham Trent University.

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As a result of Coordinate Measuring Machines (CMMs) becoming widely used in industry, a need to link CAD and inspection together and program CMMs off-line has emerged. The work undertaken for this research involves the development of a software interface to link any CAD system with any CMM utilising standard data exchange interfaces. The IGES (Initial Graphics Exchange Specification) interface was used for a limited two way communication with any CAD system and the DMIS (Dimensional Measuring Interface Specification) interface was used for improved communication with the CMM. Although the CAD systems tested were AutoCad and Unigraphics, it is expected that other systems too could be used easily for the data transactions.

The system was developed using the C++ language, to run on any PC with a VGA colour monitor. The different modules created and their functions are:
1. An IGES post processor to read 21/2D information from a CAD system.
2. A user interface to allow interaction with the extracted CAD data, to create the inspection model. This involves using the keyboard, mouse and monitor. In order to create the inspection model, the user has to select the features which are to be measured and apply the corresponding tolerances to them. Then the user has to define the measurement sequence and if needed generate a 'shorter' measurement path. A limited error avoidance algorithm is incorporated.
3. A pre-processor to create DMIS and CMES output files, to drive the CMM to measure the created inspection tasks.
4. A simulation of the movements of the measuring probe on the screen, when the inspection programs are executed.
5. A post-processor to read DMIS output programs and get the measured values into the system. The measured features and their values will be displayed in different colours depending on whether they are within or outside the tolerances. 6. A pre-processor to write an IGES file and input the measured values into the CAD system.

The results of the IGES/DMIS inputs and outputs have been successfully tested for all the features provided by the system in 2V4D parts several times to ensure the application was working properly. The limitations of the system are presented.

Item Type: Thesis
Creators: Liebar, A.M.
Date: 1993
ISBN: 9781369323177
Divisions: Schools > School of Science and Technology
Record created by: Linda Sullivan
Date Added: 01 Oct 2020 15:21
Last Modified: 22 Sep 2023 13:56

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