Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s in...Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s include system design, integration of object-oriented technology, data distri bution, collaborative and distributed manufacturing working environment, secur ity, and web-based integration. However, there are limitations on their rese arches. In particular, they cannot cater for PDM in distributed manufacturing e nvironment. This is especially true in South China, where many Hong Kong (HK) ma nufacturers have moved their production plants to different locations in Pearl R iver Delta for cost reduction. However, they retain their main offices in HK. Development of PDM system is inherently complex. Product related data cover prod uct name, product part number (product identification), drawings, material speci fications, dimension requirement, quality specification, test result, log size, production schedules, product data version and date of release, special tooling (e.g. jig and fixture), mould design, project engineering in charge, cost spread sheets, while process data includes engineering release, engineering change info rmation management, and other workflow related to the process information. Accor ding to Cornelissen et al., the contemporary PDM system should contains manageme nt functions in structure, retrieval, release, change, and workflow. In system design, development and implementation, a formal specification is nece ssary. However, there is no formal representation model for PDM system. Theref ore a graphical representation model is constructed to express the various scena rios of interactions between users and the PDM system. Statechart is then used to model the operations of PDM system, Fig.1. Statechart model bridges the curr ent gap between requirements, scenarios, and the initial design specifications o f PDM system. After properly analyzing the PDM system, a new distributed PDM (DPDM) system is proposed. Both graphical representation and statechart models are constructed f or the new DPDM system, Fig.2. New product data of DPDM and new system function s are then investigated to support product information flow in the new distribut ed environment. It is found that statecharts allow formal representations to capture the informa tion and control flows of both PDM and DPDM. In particular, statechart offers a dditional expressive power, when compared to conventional state transition diagr am, in terms of hierarchy, concurrency, history, and timing for DPDM behavioral modeling.展开更多
In the course of network supported collaborative design,the data processing plays a very vital role.Much effort has been spent in this area,and many kinds of approaches have been proposed.Based on the correlative mate...In the course of network supported collaborative design,the data processing plays a very vital role.Much effort has been spent in this area,and many kinds of approaches have been proposed.Based on the correlative materials,this paper presents extensible markup language(XML)based strategy for several important problems of data processing in network supported collaborative design,such as the representation of standard for the exchange of product model data(STEP)with XML in the product information expression and the management of XML documents using relational database.The paper gives a detailed exposition on how to clarify the mapping between XML structure and the relationship database structure and how XML-QL queries can be translated into structured query language(SQL)queries.Finally,the structure of data processing system based on XML is presented.展开更多
Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of g...Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of geometric accuracy and surface finish, can be enhanced by using the product manufacturing information(PMI) stored in the neutral standard for the exchange of product model data(STEP) file, thereby integrating design and manufacturing. The present paper proposes a unique fixture design approach, to extract the geometry information from STEP application protocol(AP) 242 files of computer aided design(CAD) models, for providing automatic suggestions of locator positions and clamping surfaces. Automatic feature extraction software "FiXplan", developed using the programming language C#, is used to extract the part feature, dimension and geometry information. The information from the STEP AP 242 file is deduced using geometric reasoning techniques, which in turn is utilized for fixture planning. The developed software is observed to be adept in identifying the primary, secondary, and tertiary locating faces and locator position configurations of prismatic components. Structural analysis of the prismatic part under different locator positions was performed using commercial finite element method software, ABAQUS, and the optimized locator position was identified on the basis of minimum deformation of the workpiece.The area-ratio(base locator enclosed area(%)/work piece base area(%)) for the ideal locator configuration was observed as 33%. Experiments were conducted on a prismatic workpiece using a specially designed fixture, for different locator configurations. The surface roughness and waviness of the machined surfaces were analysed using an Alicona non-contact optical profilometer. The best surface characteristics were obtained for the surface machined under the ideal locator positions having an area-ratio of 33%, thus validating the predicted numerical results. The efficiency, capability and applicability of the developed software is demonstrated for the finishing operation of a sensor cover – a typical prismatic component having applications in the naval industry, under different locator configurations.The best results were obtained under the proposed ideal locator configuration of area-ratio 33%.展开更多
With the globalization and diversification of the market and the rapid development of Information Technology(IT)and Artificial Intelligence(AI),the digital revolution of manufacturing is coming.One of the key technolo...With the globalization and diversification of the market and the rapid development of Information Technology(IT)and Artificial Intelligence(AI),the digital revolution of manufacturing is coming.One of the key technologies in digital manufacturing is product digital modeling.This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle,then researches on the three critical technologies of digital modeling in digital man-ufacturing-product modeling,standard for the exchange of product model data and digital product data management.And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features,applies STEP as data ex-change mechanism,and establishes PDM system to manage the large amount,complicated and dynamic product data to implement the product digital model data exchange,sharing and integration.展开更多
To overcome the limitations of commercial CAD and handbook form of knowledge expression, the Distributed Knowledge Information System (DKIS) for product design is proposed. The structure of DKIS and the key issues in...To overcome the limitations of commercial CAD and handbook form of knowledge expression, the Distributed Knowledge Information System (DKIS) for product design is proposed. The structure of DKIS and the key issues in its implementation are introduced; the method of knowledge store and transfer of DKIS is discussed. The mechanism of knowledge representation, acquisition and utilization, based on Internet network, is achieved. Based on the concept of function driven, integrated Artificial Neural Networks and Active Server Pages techniques, transplanting the trained ANN into DKIS system, a new method for retrieving knowledge in DKIS over Internet is achieved. Finally, a prototype of DKIS is developed to demonstrate the feasibility of the structure and constructional method of DKIS. The work pro-vides a scheme for speed knowledge acquisition and shortens the cycle of product development.展开更多
This paper uses semantic data modelling and CAD/CAPP/CAM integration to analyze the features defined in the STEP AP214, its characteristics of definition and distribution, and its influence on the complexity of CAD/CA...This paper uses semantic data modelling and CAD/CAPP/CAM integration to analyze the features defined in the STEP AP214, its characteristics of definition and distribution, and its influence on the complexity of CAD/CAPP/CAM application integration. A framework is developed for applications of CAD/CAPP/CAM integration based on the STEP to reduce the complexity of integration implementation. Two application program interfaces (API), namely, application protocol API and application API, are developed. The frameworks hierarchy structure and the application program interfaces between the layers make the integration of applications easier.展开更多
文摘Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s include system design, integration of object-oriented technology, data distri bution, collaborative and distributed manufacturing working environment, secur ity, and web-based integration. However, there are limitations on their rese arches. In particular, they cannot cater for PDM in distributed manufacturing e nvironment. This is especially true in South China, where many Hong Kong (HK) ma nufacturers have moved their production plants to different locations in Pearl R iver Delta for cost reduction. However, they retain their main offices in HK. Development of PDM system is inherently complex. Product related data cover prod uct name, product part number (product identification), drawings, material speci fications, dimension requirement, quality specification, test result, log size, production schedules, product data version and date of release, special tooling (e.g. jig and fixture), mould design, project engineering in charge, cost spread sheets, while process data includes engineering release, engineering change info rmation management, and other workflow related to the process information. Accor ding to Cornelissen et al., the contemporary PDM system should contains manageme nt functions in structure, retrieval, release, change, and workflow. In system design, development and implementation, a formal specification is nece ssary. However, there is no formal representation model for PDM system. Theref ore a graphical representation model is constructed to express the various scena rios of interactions between users and the PDM system. Statechart is then used to model the operations of PDM system, Fig.1. Statechart model bridges the curr ent gap between requirements, scenarios, and the initial design specifications o f PDM system. After properly analyzing the PDM system, a new distributed PDM (DPDM) system is proposed. Both graphical representation and statechart models are constructed f or the new DPDM system, Fig.2. New product data of DPDM and new system function s are then investigated to support product information flow in the new distribut ed environment. It is found that statecharts allow formal representations to capture the informa tion and control flows of both PDM and DPDM. In particular, statechart offers a dditional expressive power, when compared to conventional state transition diagr am, in terms of hierarchy, concurrency, history, and timing for DPDM behavioral modeling.
基金supported by National High Technology Research and Development Program of China(863 Program)(No.AA420060)
文摘In the course of network supported collaborative design,the data processing plays a very vital role.Much effort has been spent in this area,and many kinds of approaches have been proposed.Based on the correlative materials,this paper presents extensible markup language(XML)based strategy for several important problems of data processing in network supported collaborative design,such as the representation of standard for the exchange of product model data(STEP)with XML in the product information expression and the management of XML documents using relational database.The paper gives a detailed exposition on how to clarify the mapping between XML structure and the relationship database structure and how XML-QL queries can be translated into structured query language(SQL)queries.Finally,the structure of data processing system based on XML is presented.
基金Department of Science and Technology,Government of India for providing financial support under the scheme FIST(No.SR/FST/ETI-388/2015)。
文摘Fixture design and planning is one of the most important manufacturing activities, playing a pivotal role in deciding the lead time for product development. Fixture design, which affects the part-quality in terms of geometric accuracy and surface finish, can be enhanced by using the product manufacturing information(PMI) stored in the neutral standard for the exchange of product model data(STEP) file, thereby integrating design and manufacturing. The present paper proposes a unique fixture design approach, to extract the geometry information from STEP application protocol(AP) 242 files of computer aided design(CAD) models, for providing automatic suggestions of locator positions and clamping surfaces. Automatic feature extraction software "FiXplan", developed using the programming language C#, is used to extract the part feature, dimension and geometry information. The information from the STEP AP 242 file is deduced using geometric reasoning techniques, which in turn is utilized for fixture planning. The developed software is observed to be adept in identifying the primary, secondary, and tertiary locating faces and locator position configurations of prismatic components. Structural analysis of the prismatic part under different locator positions was performed using commercial finite element method software, ABAQUS, and the optimized locator position was identified on the basis of minimum deformation of the workpiece.The area-ratio(base locator enclosed area(%)/work piece base area(%)) for the ideal locator configuration was observed as 33%. Experiments were conducted on a prismatic workpiece using a specially designed fixture, for different locator configurations. The surface roughness and waviness of the machined surfaces were analysed using an Alicona non-contact optical profilometer. The best surface characteristics were obtained for the surface machined under the ideal locator positions having an area-ratio of 33%, thus validating the predicted numerical results. The efficiency, capability and applicability of the developed software is demonstrated for the finishing operation of a sensor cover – a typical prismatic component having applications in the naval industry, under different locator configurations.The best results were obtained under the proposed ideal locator configuration of area-ratio 33%.
文摘With the globalization and diversification of the market and the rapid development of Information Technology(IT)and Artificial Intelligence(AI),the digital revolution of manufacturing is coming.One of the key technologies in digital manufacturing is product digital modeling.This paper firstly analyzes the information and features of the product digital model during each stage in the product whole lifecycle,then researches on the three critical technologies of digital modeling in digital man-ufacturing-product modeling,standard for the exchange of product model data and digital product data management.And the potential signification of the product digital model during the process of digital manufacturing is concluded-product digital model integrates primary features of each stage during the product whole lifecycle based on graphic features,applies STEP as data ex-change mechanism,and establishes PDM system to manage the large amount,complicated and dynamic product data to implement the product digital model data exchange,sharing and integration.
基金the National Natural Science Foundation of China (No.59990472).
文摘To overcome the limitations of commercial CAD and handbook form of knowledge expression, the Distributed Knowledge Information System (DKIS) for product design is proposed. The structure of DKIS and the key issues in its implementation are introduced; the method of knowledge store and transfer of DKIS is discussed. The mechanism of knowledge representation, acquisition and utilization, based on Internet network, is achieved. Based on the concept of function driven, integrated Artificial Neural Networks and Active Server Pages techniques, transplanting the trained ANN into DKIS system, a new method for retrieving knowledge in DKIS over Internet is achieved. Finally, a prototype of DKIS is developed to demonstrate the feasibility of the structure and constructional method of DKIS. The work pro-vides a scheme for speed knowledge acquisition and shortens the cycle of product development.
文摘This paper uses semantic data modelling and CAD/CAPP/CAM integration to analyze the features defined in the STEP AP214, its characteristics of definition and distribution, and its influence on the complexity of CAD/CAPP/CAM application integration. A framework is developed for applications of CAD/CAPP/CAM integration based on the STEP to reduce the complexity of integration implementation. Two application program interfaces (API), namely, application protocol API and application API, are developed. The frameworks hierarchy structure and the application program interfaces between the layers make the integration of applications easier.
