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An Integration Framework for Digital Progressive Die Design and Manufacturing WANG Guoxian1 ZHANG Wenzu2 A Y C Nee 1 1 Department of Mechanical Engineering National University of Singapore 10 Kent Ridge Crescent Singapore 119260 E mail engp1724 nus edu sg 2 Institute of High Performance Computing 1 Science Park Road 01 01 The Capricorn Science Park II Singapore 117528 Abstract This paper reports an effort to develop an intelligent integration f ramework f or digital progressive die design and manufacturing Both data and process centric integration functions are provided by the framework as if a special ight weight PDM PLM Product Data Management Product Lifecycle Management and WM Workflow Management system is embedded in the integrated engineering environment A f lexible integration approach based on the CAD Computer A ided Design f rame work tenet is employed to rapidly build up the system while the intrinsic characteristics of the process are comprehensively taken into account Introduction of this integration f ramework would greatly improve the dynamic performance of theoverall progressive die design and manuf acturing process Keywords progressive die digital manufacturing product data integration process integration integration f ramework 1 Introduction With the expansion of computing power and its application to an ever greater range of tasks involved in the product development process modern manufacturers are greatly dependent on the Digital Manufacturing DM environment a new generation of Computer Integrated Manufacturing System CIMS While stand alone DM hardware and software tools are crucial components providing benefits individually the overall product develop ment process is most effective only after these tools are completely integrated within a common product data and process model T his fostered considerable research efforts to develop integration frameworks 1 2 or agent based architectures 3 4 to establish a tight link between product design data and the manufacturing processes plant and resource information Historically autonomous disciplines such as CAD CAE Computer Aided Engineer ing CAM Computer Aided Manufacturing and even production planning are thus brought together in a common workflow that enables the sharing of important product updates changes and revisions In design and manufacturing of progressive dies which are a type of stamping tool used to mass produce sheet metal components several suites of engineering AI Artificial Intelligence and VR Virtual Reality tools modules have been introduced which greatly improved the development process performance However progress in data and process integration solutions for all these toolsseems to lag behind advances of the DM tech nologies For example a recently reported research has only addressed the integration of a subset of design activ ities from product re modeling to stamping process planning within the full progressive die development pro cess see Fig 1 using the knowledge based blackboard architecture 10 which itself seems to be inferior to the currently more popular architecture MAS Multi Agent System Hardly any research can be found on the in tegration of the full die development cycle T his paper presents an integration framework providing a common software infrastructure for the tool suite achieved in the IPD Intelligent Progressive Die initiative 5 6 and fur ther the downstream die component manufacturing or CAPP Computer Aided Process Planning tools so that the full die development process from design to manufacturing can be cohesively integrated 2 The IPD Initiative T he integration framework presented in this paper isan extension of the IPD system developed and contin uously upgraded by the National University of Singapore and the Institute of High Performance Computing in Singapore The IPD system 5 6 includes five functional modules tools i e feature based modeler unfold er process planning module die configuration module and drawing preparation module and two complementary modules i e die template manager and knowledge based Shell The design process steps with their corre sponding functional modules and outputs working on the IPD system are shown in the upper part above the dashed line in Fig 1 T he main contributions of the IPD initiative are reflected in two aspects Firstly the de 55 sign information achieved in every process step in the fully digitalized design process is stored in a suitable fea ture based form which allows reuse of the design elements i e those defined in the feature based product model and other intermediate models as well as the manufacturing knowledge to automate downstream design tasks using knowledge based feature mapping technologies Secondly it virtualizes designs using 3D virtualiza tion technology e g the 3D strip layout This provides an additional layer of design checks to reduce design er rors in the early design stage Fig 1 Progressive die design and manufacturing process flow based on IPD system and its extension 3 The Need for an Integration Framework While the IPD system provides a set of AI and VR tools for the progressive die design tasks there is still improvement for the internal integration of these tools and further with other downstream manufacturing func tions the lower part in Fig 1 Basically the integration issues addressed in the IPD system only concern se mantic interoperability between functional modules That is it has properly decomposed the complex design pro cess into a set of manageable tasks and defined suitable forms of information descriptions for these tasks so that generation of downstream descriptions can directly use the results from the upstream stage s Additionally the IPD system also allows some operational integration functions by the help of the Shell or the knowledge based Blackboard which is an accessorial module in the original IPD system The Shell includes a common knowl edge design object base and an inference engine to enable the required computational intelligence for every func tional module It provides an additional layer of links between functional modules and supports object searching and browsing which is beneficial to the process integration However from the perspective of system integra tion the Shell only functions as a dumb object store which does not provide any radical data and process man agement assistance to augment data and process integrity In the latest IPD version the computational intelli gence enabled by the Shell for each functional module is directly embedded in that individual module itself and the Shell is removed All the functional modules are separated further from each other and become more au tonomous It is highly desirable to introduce an integration framework for these autonomous modules as well as the manufacturing applications to provide intelligent data and process management assistance as if a special PDM Product Data Management PLM Product Lifecycle Management and WM Workflow Management sys 56 tem is embedded 4 The Present Approach T he present approach attempts to rapidly build up the integration framework Some basic ideas are bor rowed from the CAD Framework 7 tenet which matured in 1990 s and is widely recognized in the field of EDA Electronic Design Automation Further a range of advanced system modeling design and analysis technolo gies especially the Object Orientation OO and distributed object technology are used to identify and optimize the system functions Fig 2 Data integration and process integration for digital progressive die design and manufacturing 4 1 Data Integration and Process Integration T he main motivation to introduce the proposed integration framework is to provide data integration and pro cess integration functions for the discrete design activities carried out by the help of a collection of design and manufacturing tools With respect to the data integration functions the end users are equipped with a global da ta view of the overall progressive die development project and assisted by a set of configuration and versioning 57 management facilities All the data for a specific project are immediately centralized and well organized to allow easy searching and sharing and controlled in a special way to restrain data inconsistency With respect to the process integration functions the end users are suggested to follow a standardized process sequence design flow in terms of a collection of design activities and their precedence relationships to generate all the desired en gineering data and informed what have done what are on going and what are ready to be done currently Fig 2 shows how the data integration and process integration functions are incorporated into the progressive die de velopment cycle using an example sheet metal product for which a progressive die is developed To accomplish a full version of die design and manufacturing the end users continually consult with the design flow to make sure working on a correct task for which all the required input data are available After each individual task is accom plished the corresponding data output automatically enter the data store and managed as a configuration version Fig 2 a is a design flow for a finished version of progressive die design and manufacturing T he corresponding working GUIs Graphic User Interfaces based on the IPD tools for all the tasks are elaborately shown around the design flow Fig 2 b shows the corresponding configuration after all the design tasks are finished 4 2 The Architecture of the Overall Engineering Environment and the Functions of the Framework Based on the present approach the overall engineering environment Fig 3 consists of the progressive die design and manufacturing tools called CAX tools in general and the integration framework or a CAX Com puter Aided anything Framework an analogy to the CAD Framework 7 T he framework further comprises a Workbench application shared by all the tools the framework kernel and two databases the management database and the raw design database The management database stores metadata which owns pointers point ing to the design objects stored in the raw design database T he framework kernel is designed as a transaction processing system and makes the database enabled system functions available for invoking by the Workbench ap plication GUI directly or the CAX tools via wrappers The CAX tools can work autonomously but under the su pervision of the framework and all the design results showing the project advances would be migrated to the cen tralized repository through the framework Basically any functions shared by the tool set can be allotted to the framework However the main current concerns are the product data and process management functions for which the characteristics of the progressive die design and manufacturing process are comprehensively taken into account Therefore the framework kernel is further decomposed into three components the data and process management kernel the metadata handling component and the design data handling component Fig 3 Integrated engineering environment based on a CAX framework adapted from 7 4 3 Implementation Roadmap T hree steps are taken to build up the framework archi tecture in Fig 3 The first step is to make main implemen tation decisions to conceptualize a skeletal framework without considering the details of the management database schema The second step is to develop the management database schema or relevant information models and further specify other components in the framework with more de tails based on the database schema developed The third step is to develop the Workbench application GUI Graphic User Interface and test the framework functions from this GUI It is easy to wrap the tools so that they can directly invoke some framework functions mainly design object check in and check out within their original interfaces without the necessity to leave there and enter the Work bench GUI to invoke these functions T herefore imple mentation of the wrappers is not considered in detail in the current prototype 4 4 The Skeletal Framework Fig 4 shows the skeletal framework after the first step is finished and the functionalities in Fig 3 are par titioned between the client and server side T he main related implementation decisions are shown as follow An enterprise wide Microsoft r Windows based Intranet is supposed to be the normal working platform and both the metadata and the design data are centralized at the server side as the information hub A common OO pro gramming language Java is selected to realize all the newly created framework components ObjectStore r an OO Data Base Management System OODBMS is selected as the management database to store the metada ta Remote access to the metadata is through the requests to an application server which interacts with the meta 58 Fig 4 The skeletal framework data database and RMI Remote Method Invocation one of recognized distributed object technologies is used since both the client applications and the server applications are written in Java Transfer of a design object file is through the CIFS Common Internet File System protocol 8 jCIFS SMB client library 9 which enables any Java appli cation to remotely access shared files and directories on SMB file servers i e a Microsoft r Windows share is used to develop Java based client applications 4 5 System Modeling and the Management Database Schema According to the OO principle specifying an OO soft ware system is equivalent to the identification of a set of ob Fig 5 Overview of the information structure jects and their relationships or defining an OO model in the form like the UML Unified Modeling Language diagrams Once an adequate OO model is achieved the most creative part of the system development effort is al most finished For the system like the current integration framework which contains an OODBMS these objects can be divided into two parts either transient i e instances are internal to the application s memory or per sistence capable i e instances are stored in OODBMS T heoretical preparation and analysis should be done to lay the adequate foundation Specifically a set of IDEF0 models were used to define the context in which the framework coupling with the participating tools work properly The overall progressive die design and manufac turing process was fully characterized to capture the design change propagation properties An advanced design versioning control and configuration management model was derived to support design change propagation man agement Finally the process management model was built upon the product management model Fig 5 is an overview of the developed system model which highlights the information structure of the database schema the unshaded part It reads as follows The product and process management kernel manages all projects in OODBMS Each project hasone to n configuration versions which have a workflow and a hierarchy of design ob ject versions T he workflow is further defined as a hierarchy of design activities The components in the configu ration version or the corresponding workflow called a composition are hierarchically organized i e the com positions contain some sub compositions which can be further recursively decomposed till to the root components design objects or activities Note that the hierarchal relationships are not shown in detail to save space 4 6 The Workbench GUI T he final step is to design the Workbench GUI from which to perform carefully definedoperations to invoke the functions allotted to the framework Fig 6 shows the screenshot of the developed GUI It contains 4 win dows At the upper left are the Project Browser and Configuration Version Browser from left to right At the lower left is the Design Flow Browser At the right is the Product Hierarchy Browser To make use of the Workbench application the user first locates a project and then locates a configuration version to view its detailed working status The corresponding design flow and product hierarchy flow are then presented to the us er Among these intuitive graphic browsers the design flow browser shows the activities and their precedence relationships for a configuration version T hey are further coloured with the run time information to show 59 Fig 6 Screenshot of the GUI what has been done what is working and what needs to be done next The product hierarchy browser shows the project composition and progress status in terms of reflecting all the immediate updates on the design object ver sions It is also used to receive users operations on design objects especially the check in and check out opera tions to drive the engineering process to progress The check in operation saves an updated design object version in the common design object repository while the check out operation load a design object version in the work space from the common design object repository These operations are activated through a pop up menu attached to a selected design object All the design activities and engineering data produced are thus under good control at any time during the design course There is no need for extra searching to launch the desired operations and no confusion data are produced for engineers 5 Process Dynamics Generally introduction of the developed integration framework does not radically alter the static view of the progressive die design and manufacturing process sequence which is shown in Fig 1 However the dynamic per formance of the process would be considerably improved from the end users perspective Working in the inte gration framework enabled engineering environment the users can always have a global view of the entire pro cess and its progressstatus while performing a local design or manufacturing task Not only are the design results for the processsteps visualized but also the engineering processes Much process knowledge in terms of tasks in volved and their precedence r