19 research outputs found

    A methodology for the distributed and collaborative management of engineering knowledge

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    The problems of collaborative engineering design and management at the conceptual stage in a large network of dissimilar enterprises was investigated. This issue in engineering design is a result of the supply chain and virtual enterprise (VE) oriented industry that demands faster time to market and accurate cost/manufacturing analysis from conception. Current tools and techniques do not completely fulfil this requirement due to a lack of coherent inter-enterprise collaboration and a dearth of manufacturing knowledge available at the concept stage. Client-server and peer to peer systems were tested for communication, as well as various techniques for knowledge management and propagation including Product Lifecycle Management (PLM) and expert systems. As a result of system testing, and extensive literature review, several novel techniques were proposed and tested to improve the coherent management of knowledge and enable inter-enterprise collaboration. The techniques were trialled on two engineering project examples. An automotive Tier-1 supplier which designs products whose components are sub­contracted to a large supply chain and assembled for an Original Equipment Manufacturer (OEM) was used as a test scenario. The utility of the systems for integrating large VEs into a coherent project with unified specifications were demonstrated in a simple example, and problems associated with engineering document management overcome via re-usable, configurable, object oriented ontologies propagated throughout the VE imposing a coherent nomenclature and engineering product definition. All knowledge within the system maintains links from specification - concept - design - testing through to manufacturing stages, aiding the participating enterprises in maintaining their knowledge and experience for future projects. This potentially speeds the process of innovation by enabling companies to concentrate on value-added aspects of designs whilst ‘bread-and-butter’ expertise is reused. The second example, a manufacturer of rapid-construction steel bridges, demonstrated the manufacturing dimension of the methodology, where the early stage of design, and the generation of new concepts by reusing existing manufacturing knowledge bases was demonstrated. The solution consisted of a de-centralised super-peer net architecture to establish and maintain communications between enterprises in a VE. The enterprises are able to share knowledge in a common format and nomenclature via the building-block shareable super-ontology that can be tailored on a project by project basis, whilst maintaining the common nomenclature of the ‘super-ontology’ eliminating knowledge interpretation issues. The two-tier architecture developed as part of the solution glues together the peer-peer and super-ontologies to form a coherent system for internal knowledge management and product development as well as external virtual enterprise product development and knowledge management. In conclusion, the methodology developed for collaboration and knowledge management was shown to be more appropriate for use by smaller enterprises collaborating in a large Virtual Enterprise than PLM technology in terms of: usability, configurability, cost of system and individual control over intellectual property rights

    A framework to support semantic interoperability in product design and manufacture

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    It has been recognised that the ability to communicate the meaning of concepts and their intent within and across system boundaries, for supporting key decisions in product design and manufacture, is impaired by the semantic interoperability issues that are presently encountered. This work contributes to the field of semantic interoperability in product design and manufacture. An attribution is made to the understanding and application of relevant concepts coming from the computer science world, notably ontology-based approaches, to help resolve semantic interoperability problems. A novel ontological approach, identified as the Semantic Manufacturing Interoperability Framework (SMIF), has been proposed following an exploration of the important requirements to be satisfied. The framework, built on top of a Common Logic-based ontological formalism, consists of a manufacturing foundation to capture the semantics of core feature-based design and manufacture concepts, over which the specialisation of domain models can take place. Furthermore, the framework supports the mechanisms for allowing the reconciliation of semantics, thereby improving the knowledge sharing capability between heterogeneous domains that need to interoperate and have been based on the same manufacturing foundation. This work also analyses a number of test case scenarios, where the framework has been deployed for fostering knowledge representation and reconciliation of models involving products with standard hole features and their related machining process sequences. The test cases have shown that the Semantic Manufacturing Interoperability Framework (SMIF) provides effective support towards achieving semantic interoperability in product design and manufacture. Proposed extensions to the framework are additionally identified so as to provide a view on imminent future work.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A Case Study for Financial Feasibility of Automated Costing Support in A Small Machine Shop

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    A knowledge-based cost estimating expert system is chosen by a Mexican machine shop. Differences between the traditional experience-based system employed and the automated system are studied. Data is gathered to analyze time effectiveness, accuracy and payback of the software. Data from seventy part models is recorded to study the time experiment, and data from fifty part models is used to study the accuracy and consistency. Data is analyzed by calculating mean, standard deviation, and test of hypothesis. The results indicate that the software is faster than the traditional quoting system; however, the payback point is high. Also, results show the software has a smaller average time-to-manufacture percentage difference between the automated system and the actual time-to-manufacture (TTM) compared to the percentage difference between the traditional’s TTM and actual TTMs, and this difference is statistically significant. The standard deviation for the automated system is also less implying better consistency

    Automated feature recognition system for supporting engineering activities downstream of conceptual design.

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    Transfer of information between CAD models and downstream manufacturing process planning software typically involves redundant user interaction. Many existing tools are process-centric and unsuited for selection of a "best process" in the context of existing concurrent engineering design tools. A computer based Feature-Recognition (FR) process is developed to extract critical manufacturing features from engineering product CAD models. FR technology is used for automating the extraction of data from CAD product models and uses wire-frame geometry extracted from an IGES neutral file format. Existing hint-based feature recognition techniques have been extended to encompass a broader range of manufacturing domains than typical in the literature, by utilizing a combination of algorithms, each successful at a limited range of features. Use of wire-frame models simplifies product geometry and has the potential to support rapid manufacturing shape evaluation at the conceptual design stage. Native CAD files are converted to IGES neutral files to provide geometry data marshalling to remove variations in user modelling practice, and to provide a consistent starting point for FR operations. Wire-frame models are investigated to reduce computer resources compared to surface and solid models, and provide a means to recover intellectual property in terms of manufacturing design intent from legacy and contemporary product models. Geometric ambiguity in regard to what is ?solid? and what is not has plagued wire-frame FR development in the past. A new application of crossing number theory (CNT) has been developed to solve the wire-frame ambiguity problem for a range of test parts. The CNT approach works satisfactorily for products where all faces of the product can be recovered and is tested using a variety of mechanical engineering parts. Platform independent tools like Extensible Mark-up Language are used to capture data from the FR application and provide a means to separate FR and decision support applications. Separate applications are composed of reusable software modules that may be combined as required. Combining rule-based and case-based reasoning provides decision support to the manufacturing application as a means of rejecting unsuitable processes on functional and economic grounds while retaining verifiable decision pathways to satisfy industry regulators

    Acquisition and sharing of innovative manufacturing knowledge for preliminary design

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    This study investigates the identification, acquisition and sharing of innovative manufacturing knowledge for the preliminary design of complex mechanical components. Such components need to satisfy multiple, often conflicting design and performance requirements. Some degree of innovation may be required, involving the development of new manufacturing processes. The innovative nature of this manufacturing knowledge makes it difficult to define, codify and share, especially during preliminary design, where this can present significant risks in the design process. Current methods of knowledge sharing do not account for the immature nature of innovative manufacturing knowledge and the combined explicit and tacit elements needed to express it. A flexible interpretive research study with inductive and hypothesis testing elements was undertaken to explore this novel knowledge management problem. During the inductive phase, two data collection activities were undertaken to investigate the manufacturing knowledge required for the preliminary design of gas turbine engines. Using a data driven approach, the main findings which emerged were: the need to include an assessment of the maturity of the design process; the need to use a range of tacit and explicit knowledge to effectively share this and the need to manage knowledge across different domain boundaries. A conceptual framework of the findings was used to develop a hypothesis of knowledge requirements for preliminary design. For the hypothesis testing phase, a systematic methodology to identify, acquire and share innovative manufacturing knowledge for preliminary design was developed from the knowledge requirements. This approach allowed both explicit and tacit knowledge sharing. An evaluation of the methodology took place using three different industrial cases, each with a different component / manufacturing process. The evaluations demonstrated that using the range of knowledge types for transferring knowledge was effective for the specific cases studied and confirmed the hypothesis developed
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