A PC-BASED INFORMATION SYSTEM FOR A FLEXIBLE MANUFACTURING SYSTEM ** A. M. Shaharoun 1, A. A. Razak 1, M. I. Jambak 1 *, A. J. R. Zwegers 2 + 1

Faculty of Mechanical Engineering Universiti Teknologi Malaysia Locked Bag 791, 80990, Johor Phone: 07 - 5504566 Fax: 07 – 5566159 * E-mail: [email protected]

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Eindhoven University of Technology P.O. Box 513 Pav. H1 5600 MB Eindhoven The Netherlands Phone: 31 - 40 - 2472322 + E-mail: [email protected] Abstract This paper describes a PC-based information system to assist the operation of a Flexible Manufacturing System (FMS). An FMS requires a complete set of information in order to operate efficiently and reduce information redundancy to achieve reduced cycle-time. Hence the design of the information system has to be performed taking into consideration all the functions and entities that operate within an FMS. The paper begins by describing the modelling and design phases for developing the information system. In the design stage, IDEF0 modelling methodology was chosen for modelling physical/work flow and IDEF1x was used for modelling the information flow. The programming language and database management system that were chosen to develop the application system are MSVisual Basic 4.0 Enterprise Edition and MS-Access 2.0. Structured query language (SQL) commands executed by objects that were created in the user-interface were used to manipulate and retrieve data. This PC-based information system is cost effective, easy to develop, and easy to use in medium sized companies, which require such systems at an affordable price. This paper also examines the possibility to migrate the current database management system to larger database management systems and also from the local application to client/server applications. These are can be applied in a virtual manufacturing environment and in future distributed manufacturing system applications. Keywords PC-based, information system, database, FMS, CIM, virtual manufacturing

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Presented in MSTC’98 as Oral Presentation paper in P.Pinang and Poster paper in Johor

1. Introduction Flexible Manufacturing Systems (FMS) appeared on the scene in the early 1970s; today their number world-wide is several hundred, perhaps a thousand (Veeramani et al, 1993). An FMS can be defined as "a computer-controlled configuration of semidependent workstations and a material handling system designed to efficiently manufacture more than one type of parts ranging from low to medium volume" (Jang et al, 1996). As a computer-controlled system, an FMS is information-driven system. The information system becomes very important in an FMS or Computer-Integrated Manufacturing (CIM) system. The various controllers require information to perform their tasks on the shopfloor. The attributes of an information system that impact the operation on the shop floor are the quality of information, reliability, consistency and concurrency control, speed of operation, and adaptability (Veeramani et al., 1993). Quality of information means that the information is able to present the true representation of physical reality accurately and completely. Reliability refers to the capability of the information system to detect the malfunctions and failures at sites and to analyse the abnormal behaviour to infer its cause and effect on the system. The information system has to provide information that is consistent with reality even if the information is distributed to all sites. The information system must allow very high frequent updates to obtain the required speed of operation. The information system must be capable of adapting automatically to short-term changes and must require minimal cost to accommodate long-term changes in the manufacturing system (Veeramani et al., 1993). The database is the heart of an information system. By using a database management system (DBMS), the information needed by a user (a human been or a CNC machine or a robot working in a flexible manufacturing system) becomes accessible. The DBMS itself must support the fulfilment of requirements as described in the above paragraph. The aim of this research is to develop a suitable information system for a prototype CIM system under development within IRPA Project at Universiti Teknologi Malaysia (UTM). To generate a prototype of CIM system, UTM needs a particular information architecture that can be expanded as proposed information architecture for the CIM system. The objective of this paper is to present the PC-based information system that is being developed in UTM Faculty of Mechanical Engineering production laboratory as a case study in the CIM project. The PC-based information system must be cost effective, easy to develop, and easy to use in medium sized companies. Furthermore, the system must be provided/offered at an affordable price. Finally, the system must allow a migration to a larger database, and it must be able to become a client-server database application.

2. FMS Functional and Information Modelling Using IDEF Methodology 2.1. IDEF Methodology review “IDEF” is an acronym for the ICAM-Definition methodology – (Integrated Computer-Aided Manufacturing). The IDEF methodology was developed by the US Air Force’s ICAM program in the early 1980’s (Ranky, 1990) (Ang et al, 1989) (Ang et al., 1994). IDEF methodology is a group of methodology, which are used for modelling of particular aspects of a system (Sarkis et al., 1994) (Vernadat, 1996). Commercial tools are available that support the IDEF methodology. For this research, IDEF ™ integrated software by Meta Software Corporation was used. The approaches in this research are using the IDEF0 methodology for modelling the functions and activities in an FMS environment, and using IDEF1x to develop the conceptual relational data model. 2.2. FMS Functional Modelling Using IDEF0 The IDEF0 is a methodology and a tool for modelling the manufacturing functions. Functions are represented by blocks and linked together through inputs, outputs, controls, and mechanisms (ICOM). Functions can be decomposed into sub-functions (Wu, B., 1992) (Sarkis et al, 1994) (Ang et al., 1994) (Vernadat, 1996). Figure 1 illustrates the rough second level of an FMS functional model. It is a decomposition of the top level, and if necessary, can be decomposed to get more detailed model. WORKING READER DRAFT RECOMMENDED PUBLICATION Manufacturing Objectives / Strategy Instructions

NOTES: 1 2 3 4 5 6 7 8 9 10 I1

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Figure 1 – IDEF0 second level

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2.3. FMS Information Modelling Using IDEF1x After the FMS functional model has modelled, the FMS information model can be modelled using IDEF1x with considering the FMS functional model. The IDEF™ integrated software by Meta Software Corporation provides the integration function of IDEF0 and IDEF1x methodologies to connect every arrow in IDEF0 with the entity list and attribute list within IDEF1x. The IDEF1x language is known as EXPRESS-G as a part of the STEP standard (Vernadat, 1996). Figure 2 shows an example of the Tool information model. The model constructed by the entity, the attribute, and the relationship. An entity describes as any object that exists and can be distinguished from other objects. It is a person, a place, an event, an object, or a concept in the real world that wish to represent in the database (Ricardo, 1990). Each entity has particular properties called attributes. Relationships are connections or interactions between the entity instances. In IDEF1x, Every entity is represented by a box, and given a unique name. A parent entity (e.g., TOOL) has a relationship with a child entity.

Figure 2 IDEF1x information modelling 3. Database and User-interface Development 3.1. Physical Database Development Using MS-Access 2.0 Based on the information model, the database tables in MS-Access 2.0 have been created. MS-Access 2.0 provides a simple way to create a database table either by using its create new table object or Microsoft Access SQL commands. Here the illustration how the tool table is created using the Microsoft Access SQL commands. CREATE TABLE tool (tool_id TEXT 21, tool_name TEXT 20, supp_code TEXT 10, picture TEXT 50) CREATE UNIQUE INDEX tool_Index ON tool (tool_id)

By enforcing the referential integrity set the relationship between table can be set.

3.2. User-interface Development Using MS-Visual Basic 4.0 MS-Visual Basic provides a user-friendly object tool called custom control to be used in a form. The programmes itself are written in the custom control objects or procedures. Figure 3 shows an example of a user interface form called “frmTool.Frm”. The sample of programming in MS-Visual Basic 4.0 to connect the user interface with the database and create a data collection for data manipulation is shown as follows. Set CIMdb = OpenDatabase("C:\utm-cim\cim.mdb", False, False) Set Tooldy = CIMdb.CreateDynaset("tool")

The first version of the user-interface that being developed contains product module, design module, and manufacturing module. Sub-modules are created under these modules. The product module contains part data and product structure sub-modules. Drawing and Work-material sub-modules are under the design module. The process planning, tool database (tool, insert, holder), machine (machine, magazine, NC programming) sub-modules are included in manufacturing module. 4. Discussion IDEF ™ integrated software by Meta Software Corporation is very easy to learn and use. The IDEF0 / IDEF1x integration function does not provide the “real integration” that users need. Changing the functional model in IDEF0 does not automatically affect to the information model in IDEF1x. Users cannot create the information model with IDEF1x automatically after they have created their functional model using IDEF0.

Figure 3 MS-Visual Basic 4.0 Form

The MS-Visual Basic 4.0 has chosen because of the following reasons: • It has the same version database “Jet Engine” as Access 2.0, for this reason it is possible for us to make a data manipulation with SQL Access commands. • MS-Visual Basic 4.0 provides an object oriented programming language. The object tool custom control makes using Visual Basic easy. • MS-Visual Basic 4.0 supports OLE (Object Linking Embedded) automation to linking and embedding other applications as objects. For example this application may embed AutoCAD Release 14 object in the “Design” Module. • MS-Visual Basic 4.0 supports external database connectivity by using Microsoft ODBC (Open Database Connectivity). This reason is also considered as our approach to migrate to a larger database. Groups of company now possible to co-ordinate geographically and institutionally distributed capabilities into a single “virtual enterprise” by sharing and exchanging their information seamlessly and in real-time by computer networking and telecommunication technologies (Sng, Dennis C.H., 1997). The ODBC technology can be used in Internet or Intranet applications to realise a virtual manufacturing environment. The application that being developed in UTM production laboratory could be updated to the version that supports ActiveX to become an Internet or Intranet application. However, in this research works we found that it is not easy to migrate from MS-Visual Basic 4.0 to the higher version that supports ActiveX. 5. Conclusions This paper describes a PC-based information system. This paper proposes to use the IDEF methodology for FMS functional and information modelling. Because it is based on PC platform, this system is easy to use in medium sized companies, which require such systems at an affordable price. This system also could be migrated to a larger database easily by using a migration tool that is provided by a larger database (e.g. Oracle 8), or executing the SQL statement that created from the IDEF1x. ODBC makes it possible for a local database become a share database in client-server applications. For implementing this database in an FMS environment this will need other research efforts, e.g., in the area of networking, interfacing to the machines, and the combination of the database data with CAD data are being developed among UTM CIM group. 6. Acknowledgement This research is under IRPA grant for Universiti Teknologi Malaysia Vote Number 72091 at Faculty of Mechanical Engineering. The researchers would like to show their appreciation to dr.ir. A.J.R. Zwegers’ supports and his review on this paper.

7. References Ang, C.L. (1989), “Planning and Implementing CIM”, Computer-Aided Engineering Journal, October, pp. 167 – 176. Ang, C. L. et al. (1994), “Automatic generation of IDEF0 models”, Journal of Intelligent Manufacturing, 5, pp. 79 –92. Jang, Seong Yong et al. (1996), “An Integrated Decision Support System for FMS Production Planning and Scheduling Problems”, International Journal of Advanced Manufacturing Technology, 11, pp. 101 – 110. Martin, James and Leben, Joe (1995), Client/Server Databases: Enterprise Computing, New Jersey: Prentice Hall PTR. Meta Sofware Corporation (1997), Design/IDEF User’s Manual for Microsoft Windows, Version 3.5, Cambridge Orfali, Robert et al. (1991), “Client-server systems in manufacturing”, Special Report in I&CS, September, pp.23 – 26. Ranky, Paul G. (1990), Flexible Manufacturing Cells and Systems in CIM, Guilford, Surrey, England: CIMware Limited. Ricardo, Catherine M (1990), Database System: Principles, Design, Implementation, New York, USA: Macmillan Publishing Company Sng, Dennis C.H. (1997), “A CALLS Framework for Electronic Commerce in Virtual Manufacturing Enterprise”, Proceeding of 4th International Conference Computer Integrated Manufacturing, Singapore, Sen, A. et al. (ed), Singapore: Springer. Sarkis, Joseph and Lin, Li (1994), “An IDEF0 functional planning model for the strategic implementation of CIM systems”, International Journal of Computer Integrated Manufacturing, Vol 7, No. 2, pp.100 – 115. Veeramani, D. et al (1993), “Information system architecture for heterarchical control of large FMSs”, Computer Integrated Manufacturing, Vol 6, No.2, pp. 76 – 91. Vernadat, F.B. (1996), Enterprise Modeling and Integration: Principles and Application, England: Chapman & Hall. Wu, B (1992), Manufacturing System Design and Analysis, 2nd Ed, London, UK: Chapman & Hall.