Resource-Independent Computer Aided Inspection

  • Hesham Mahmoud

Student thesis: Doctoral ThesisPhD


Quality is of paramount importance when establishing and maintaining market share in any manufacturing sector. Measurement is a critical tool in ensuring product conformance and is a major enabler in the control of manufacturing processes to improve and maintain quality. Furthermore, measurement is evolving into a value-adding process in its own right and the gained measurement knowledge has become crucial for both design and manufacturing stages. Despite this ever increasing importance, measurement planning and execution is still carried out with great reliance on manual operations and ambiguous practice guidelines utilising tools and software that are very specific to the individual pieces of equipment used in the measurement process. In addition, in industry, measurement plans are defined in isolation instead of in an integrated and interoperable manner with other manufacturing activities. This research aims to formulate an interoperable integration framework for defining measurement processes through the introduction and realisation of resourceindependent measurement specifications (REIMS). REIMS is a data model that represents both measurement features and operations to enable their exchange between computer aided for x (CAx) applications. REIMS enables measurement process definitions to be exchanged between various measurement geographical locations and resources within a distributed manufacturing system. It, therefore, reduces the recently identified variability due to the measurement planning phase that varies depending on the experience and skills of the measurement operators. REIMS also removes an integration barrier at the measurement planning-execution interface and assists in obtaining consistent measurement knowledge. Comparable measurement knowledge is crucial for taking proper decisions for improving both design and machining phases. This thesis uses system engineering methods for analysing the measurement process and its data flow and requirements. As a result of this analysis, the REIMS data model has been developed based on the STEP modelling and implementation mechanisms to formulate a computer interpretable format of the measurement process data. STEP-based methods have been selected as the framework as they have been previously validated for interoperable data exchange between design and machining applications. The theoretical basis of REIMS is the concepts and definitions presented in the ISO standardised documents for “geometric product specifications (ISO GPS)” as these documents, for the first time in the domain, consider design specifications and measurement activities in relation to each other. The REIMS data model has been realised and a prototype implementation has been designed utilising the CTC-01 test case encoded as an ISO10303-242 compliant model. This test case has previously been used by the national institute of standards and technology (NIST) for validating the exchange of design data including product manufacturing information (PMI) between different CAD systems and as such provides an authoritative example. The implementation framework uses C++ and ST-Developer to obtain the design information from the AP242 file data and demonstrates the ability of the REIMS data model to map design specifications into measurement features and to define the necessary measurement operations to complete the process definition. An ISO10303-21 compliant file has then been constructed from the REIMS data to establish the proposed data exchange mechanism. Based on the findings of this thesis, the REIMS provides a coherent, comprehensive and flexible framework for representing the measurement process. Through adoption of REIMS as the standardised framework for measurement planning, companies could ensure the consistency of the measurement knowledge that is gained and maintained in the enterprise regardless of the location or equipment. This would facilitate the spread the measurement process benefits throughout the digital factory with potential for cost saving due to resource fluidity, a significant decrease in plan translation errors and reducing the equipment specific training requirements
Date of Award23 Nov 2016
Original languageEnglish
Awarding Institution
  • University of Bath
SponsorsThe Egyptian Government
SupervisorVimal Dhokia (Supervisor) & Aydin Nassehi (Supervisor)

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