Integrated Product Development in CIM environment for conventional and unconventional processes based on Open system and International Standard (STEP)

Morteza Sadegh Amalnik,

Computer and Automation R&D Center of ACECR-Sharif Branch,

Department of Mechanical and Industrial Engineering, University of Qum and Tabriz, Iran,

E-Mail: sadeghamalnik@yahoo.com

Abstract

Integrated Product Development (IPD) can be defined as the integration of both the product and the manufacturing design processes. It means that the product design and process plans be developed simultaneously. This is assured by having the designers work in manufacturing models, rendering the freedom to add features to the design or manipulate the process plan itself. Advanced IDP can be developed in computer integrated (CIM) environment. CIM has become fairly known in the recent years. It integrates many functions in manufacturing system, and helps to bridge the gap between CAD and CAM and other functions in manufacturing companies. During the past decade manufacturing companies have invested their financial resources on the CIM technology for keeping their companies competitive and reducing product development time, and cost and increasing productivity, market share, and benefit. While more than 70 % of final product cost set during the product design cycle, and integration of CAD and CAM are supposed to improve product development time and bring benefit for manufacturing companies. Today one of the greatest opportunities for gaining the competitive edge lies in the integration of the various islands of automation that emerged within manufacturing organizations as they have grown in size, and therefore in complexity, to bring them closer to continuous automated process. This increase in integration will result in increased quality, better price management and a vast increase in responsiveness to the market place. As between 70 to 80 percent of the cost of the product is determined at design stage. IPD cannot ever become a reality without the use of open system, international standard, a certain amount of people, and human knowledge, that are effectively used in the organization. The integration of sub-system in a manufacturing organization is not enough. People and more importantly, their associated intelligence are needed to optimise the manufacturing capabilities of any organization. In this paper a computer based IDP based on open system and international standard (STEP) is developed to integrate design and manufacturing. Various expert systems is developed to evaluate design in terms of manufacturability, and select optimum processes for each design features. The goal of integrated product development (IPD) is to reduce the product development time, to reduce the cost, shorter time to market and to provide a product that better meets the customer’s expectations. For effective IPD, It is important to develop an open system and using international standard and expert system.

Introduction

The world wide competitive economy is facing us to utilize fully the best equipment and techniques available with efficient control of organizational structure and culture to produce well designed products at lower prices in less time with high quality and shorter time to market. This means that the decision makers must be able to understand clearly their internal and external environment and be able to make decisions based upon real time information from their environment. There are many factors that organization should be considered in order to make decision quickly and properly. In traditional system, designers first create a design specification based on market specification and then product concept, preliminary design, and approval of customers, and detailed design will be performed. During the design stages, process planners, production planners, N.C. tape programmer, tools fixture designers, marketing, and other functions in manufacturing systems have no influence on the design, due to the fact that they work in another department .In the traditional design, the products designed are not perfect after detailed design and release. And any modification after detailed designed increase the development time and cost and delay to the market. Any fault in the processes of product design causes to reduce market share and profit, because the stage of product design becomes longer. Improvement of product’s design will be possible if the cost of changes is less than the amount of money, which is pre-determined. By increasing market competition and market demands and using advance technology, and increasing R& D resources and sharing in the R&D consultant, the average development time for new product becomes longer than the product’s average life expectancy. In many advanced manufacturing systems such as the Ford motor company, the cost of raw material is about 50 % and the cost of design is 5 % of the overall cost of a new product, as a result, the cost of raw material with respect to the design is ten times of design cost, but raw material influence only 20 % of an overall cost, but in contrast, the design influenced 70 % of the overall cost.

In the product design most changes should be made in earlier stage of new product design, because in the earlier stage the cost of changes will be lower, but in the later stage, the cost of changes will be much higher. In the earlier stage most modification and changes are made at design stage, before in pilot plant. Lack of success in the pilot plant causes the change in conceptual design and engineering thinking or changing product specification and redesign product. The result causes delay and increases product’s development time, and cost and reduces profit and market share. In traditional product development there is a boundary between each function and groups and all engineering functions are sequential which causes increasing new product development and cost, and reducing profit and market share. By rapid market competition and increasing advanced manufacturing systems, and using new hardware and software, international standard and expert system, and other various tools, Product life cycles become increasingly short. Companies try to perform differently in the various stages of product life cycle. Shorter of product life cycle causes many problems for companies. And companies try to accelerate product life cycle in stage1 (introduction) and stage 2 (growth), but extend stage 3 (maturity and saturation) as long as possible. During the past two decade, the average developing of a new product (such as car) changes from 7 years to 5 years, and presently at 3 or less than 3 years. Customer expectations cause to reduce developing time of the new product. The most important priority in reduction of profit caused by different problems. The important factor in reduction of profits is delays, cost and quality. Six months late to market causes 33% reduction of profits, and access of 9% cost of product causes 22% reduction of benefits. Integrated product development in CIM environment based on open system and international standard is one of the solutions.

CIM has been discussed in the literature from different approaches [1-5]. In the possible terms, CIM is a function of three elements, hardware, software and human knowledge representation. Hardware consists of two elements Computers and Networks. It is clear that without the appropriate software packages the concept of CIM will never become a reality. Without the appropriate software to run the computers then integration can never come to pass.

The tool of CAD and CAM are being used to great effect, in the effort to increase the efficiency of the engineering design and manufacturing functions. However, this requires further enhancement if the overall effectiveness of the organization is to be achieved. Integrated product development has a key role to play the computer integrated manufacturing system (CIMS) and extend to which the concurrent engineering principles are applied, will be the major deciding factor of the competitiveness of a nation's industries. However, full implementation of concurrent engineering is still far from reality [6]. CAD and CAM is in fact the heart of computer based integrated product development. It must be considered as the information pump, which will serve the central base in which all the engineering and management and other information resides.

Many managers and directors as well as manufacturing engineers are frustrated with many different databases created for a single product. They are constantly seeking a single source for all information on the product. This problem might be resolved by using the concept of single database (SDB) that includes all the data from design, analysis, process planning, tooling, quality as well as BOM, MRP, production scheduling and post process information etc. The purpose of this dynamic database is to provide the organization with a single view of engineering, design, manufacturing, research & development, marketing, purchasing, finance, accounting, customer, supplier and management information throughout the life cycle of product development. CAD vendors have created very good geometry tools which when the design is completed; the details are passed on to the manufacturing functions. This however is not enough for integrated product development to succeed. What is required is intelligent, unambiguous product information to all of the engineering functions. To day manufacturing companies are looking for a system, which is able to reduce lead time, and product development time and process, and also reduce overall cost, and increase productivity, quality, market share, and profit. Integrated product development is an answer to this requirement.

Computer based IPD can be defined as “an organizational strategy". The main idea is to reduce the time of product design by using computer based simultaneous planning of product and process. The people in different disciplines in the manufacturing system working together during the product design phase so that the demands on the means of production are specified at the very earliest moment.

In many manufacturing company’s communication and coordination between different function and department usually takes place in hierarchical ladders, and organizational walls, In this kind of organizations flexibility is very difficult, but in a computer based IPD and in a flatter organizational hierarchy, generally enhances organizational flexibility. So it is necessary to change the hierarchical structure and to reduce the level of hierarchical structure as less as possible. IPD consist of people from all function associated with product design and process from marketing people to design and manufacturing and others functions depending on a company’s culture and organization al structure. Changing the culture to achieve parallel activities is not easy task and the choice of members of the concurrent engineering teamwork is essential to its success, especially in a mature industry where the age of the engineering staff could be high [7].

One important aspect of IPD is creation of very good internal environment and culture that every one respect each other and work freely and surely and job and responsibility of each member is secured. The internal environment of IPD embraces the following aspects; 1) Trust 2) Confidence 3) Computer based team work 4) Autonomy 5) Flexibility 6) Flow of information 7) Investment and equipment and machinery 8) Responsibility, 9) management and10) motivation, 110 using hardware and software, Expert system and international standard. IDP can be defined as the integration of both the product and the manufacturing design processes. It means that the product design and process plans be developed simultaneously. This is best assured by having the designers work in manufacturing models, rendering the freedom to add features to the design or manipulate the process plan itself [8]. The goal of integrated product development is to reduce the product development time, to reduce the cost, shorter time to market and to provide a product that better meets the customer’s expectations. Integrated Product Development is a complex activity. When designing a product and process, it is important to remember that the design should be considered as a whole and therefore all related components and information should be considered interactively. Continuously developed computer technologies, in both hardware and software have given team members from different departments the ability to work with the same design to evaluate the effects of design attributes. In this context, it is believed that a significant educational program is necessary that each member fully understand the philosophy of the integrated product development. Numerous papers have reported case studies in which the team-based approaches were implemented and significant benefit were realized [9-10]. While the team based approach can be readily implemented and is being widely adopted in industry, some shortcomings appear to arise [11]: difficulties in effective management of the team, team member's limited knowledge, and the cost of maintaining a team. As more sophisticated computer tools emerge constantly, the team based approach in which the integrated product development philosophy is woven into the internal logic operations, enabling design justification or optimisation with respect to the entire aspects of a product's life cycle. A constraint programming language has been developed for designers to take into account all life cycle implications related to the product [12]. The integrated system that does not require any human intervention may yield significant advantages to reduce the product realization time, increase product quality, and reduce the cost. More detail is in [13-18].

Standard for the exchange of product (STEP)

This is the international standard (ISO) that was developed as a result of international collaboration between organisations such as CAD*I (ESPRIT) project 322, and IGES|PDES Organizations in the USA, those who have been developing current formats, to produce a formal specification, testing and implementation aids, together with documented procedures, so all the objectives to the current formats are met. As an international standard it incorporates the experience that has been accumulated over the years from the national standards such as IGES, SET, and VDA. ISO is a collection of standards for the computer interpretable representation and exchange of product information. Its objective is to provide a mechanism that is capable for describing product data throughout the life of the product, independent from any particular computer system, i.e. in a neutral format. The nature of this description makes it suitable not only for neutral file exchange, but also as a basis for implementing and sharing product databases and archiving, and for direct access to product data by application programs.

Open System

Open system is a term, which is much used but rarely understood. For end user, open system means choices and challenges. In order companies become less dependent on their equipment and their systems, they need to learn how to function within a different and freer marketplace. To day one of the important strategic issue is the efficient use of information technology for maximum use of resources in the complex and increasingly competitive environments. Manufacturing systems are needed to adapt information systems strategy based on open systems. There are two important factors that are considered for employing information technology by any organization; 1) its cost; and 2) its performance. The computer industry needs to find ways to allow both developers and potential users the ability to utilize new technology faster than they are using at present, while at the same time isolate them as much as possible from the detail of changes within. In other words it should be made easy to use, while at the same time designed in such a way that allow innovation and competitiveness among suppliers to proceed. The only way to do this requirement it is necessary to use international standard systems, supported by the computer industry, and set in such a way that reflect the real needs and priorities of the market.

Integrated Product Development

Manufacturing systems comprise of a large number of different stages that affect product cost, product quality and the productivity of the overall system. The interactions between these various processes of a manufacturing system are complex. As mentioned before, IPD is a systematic approach to integrate design of products and their related processes, including manufacture and support. This approach is intended to cause the developers, from the outset, to consider all elements of the product life cycle from conception through disposal, including quality, cost, schedule, and user requirements. Since IPD uses multi-disciplinary team and considers the product and processes at the same time, it supports right-first-time designs, which address all the product requirements such as customer attributes, functionality, reducibility, assimilability, maintainability, and recyclables. Using the CE approach for product development, not only the number of redesigns is reduced, but also changes are made at early stages of product development. IPD in CIM environment based on open system and international standard (STEP) for product data exchange is demonstrated in Figure 1. Considering all aspect of product and process development and services in the early stages of design process is demonstrated in figure 2. Each design feature requires a manufacturing process. For selection of optimum processes one can used various expert systems to generate alternative processes and select automatically the optimum process. This is demonstrated in figure 3.

Knowledge Based Systems for generation of alternative process in IPD environment

A few KBS systems is developed in IPD environment. One of the KBS is USM for ultrasonic has been developed in a computer based CIM environment; the latest version (3) of an expert system shell (NEXPERT), based on object-oriented techniques (OOT) is used to develop the knowledge base. A Hewlett Packard (HP) model 715/80-work station was used as the hardware for development of the expert systems. A geometric specification of the features of the component sent for manufacturability evaluation for the various stages of its design. Within the manufacturability procedure, the cost and cycle time and penetration rate of USM is estimated. In the design of a part, its features can be described in terms of its geometry, its particular its volume and the amount of material has to be subsequently removed.

The attributes of six different classes of work piece materials, three types of abrasive and two type of tool material are stored in database. The IKBS can retrieve information from databases and advise the designer on the appropriate choice of material, design feature description and machine type for his decision. The IKBS also contains information for manufacturability evaluation, Knowledge of design representation in three dimensions in terms of features, rules for good practice, machine and process capabilities and constraints of features that can be manufactured by a particular process. For all KBS, knowledge has been gathered from experiments on USM at Edinbrough Universities and also from technical journals and handbooks. For each design feature undergoing evaluation for manufacturability, the cost and time of the machine cycle, and penetration rate and productivity is a major consideration.

Conclusion

In this paper a computer based IDP based on open system and international standard (STEP) is developed to integrate design and manufacturing and all function in manufacturing organization. Various expert systems is developed to evaluate design in terms of manufacturability, and select optimum processes for each design features. The goal of integrated product development (IPD) is to reduce the product development time, to reduce the cost, shorter time to market and to provide a product that better meets the customer’s expectations. For effective IPD, It is important to develop an open system and using international standard and expert system. Various expert systems is developed to evaluate manufacturability, machining time and cost, and give some advice to designers for selection of design’s parameters. For example an intelligent advisory and manufacturability evaluation for Ultrasonic machining in IPD environment based has been developed. A feature-based approach is used to obtain design feature description. Expert systems are developed to assist product designers to estimate machining cycle time and cost and all other machining parameters mentioned above at the early stages of design process and give some advices for improvement of design specification. It also assists manufacturing engineers to select the optimal process parameters. In the developed system, both heuristic and algorithmic procedures have been implemented. An experimental verification has been conducted for each expert system. The developed systems allows for additional more detailed function modules or databases without altering the rest of the knowledge base. The system is user-friendly and can be used either by designer or manufacturing engineers.

Figure 1. Integration of all functions in CIM environment based on open system and international standard

Figure 2. Consideration of all aspect of product, process and services at the early stage of design

Figure3. Integration of all process KBS, in IPD and CIM environment

References

1. Sadegh Amalnik Morteza & Alitavoli, A. A Generic IDEF0 Model of an Integrated Product Development in CIM environment based on Concurrent Engineering. in: G. Rzevski, R. A. Adey, Russell (Eds), Application of Artificial Intelligence in Engineering 9, Computational Mechanics Publications, 1994, pp. 455

2. Khorami, Massih Tayebi, Bridging the Gap between CAD and CAM by Intelligent Generative Integrated Process Planning System" , PH.D. Thesis, Strathclyde University 1991 Ronald W. Garrett, Eight steps to simultaneous engineering, manufacturing engineering, Nov. 1990

3. Vail Peter,(1992) " Computer Intgrated Manufacturing, 1986

4. Ranjit Kumar Maji, Design Philosophy of Advanced Manufacturing System, Ph.D. Thesis, Strathclyde University, 1986

5. Jo and Parsaei Hamid R. and Sullivan William G., Principles of concurrent Engineering, in Concurrent engineering, edited by Parsaei Hamid R. and Sullivan William G. 1993 ,Chapman & Hall

6. Gilroy Tony J, People and organisation in managing simultaneous engineering, Simultaneous engineering, Proceeding of the first international conference, London, UK, Dec.1990

7. Cutkosky M. R and Tenenbaum J.M.(1990),"Mechanism and Machine Theory, 25,(3) 365-81

8. Allen,C. W.(ed)(1990),Simultaneous Engineering: Integrating manufacturing and design ,Society of Manufacturing Engineers, Dearborn,MI.

9. Dwivedi Suren N. and Klein Barry R., (1986), "Design for manufacturability makes dollars and sense", University of Carolina Charlotle, NC, US

10. O'Grady,P. and Young R.F.(1991), Journal of design and manufacturing, 1, 27-34.

11. O'Grady, P. and Young, R.E.(1992)," Constraint nets for life cycle engineering: concurrent engineering, proceeding of the 1992, NSF Design and Manufacturing Systems, Conference, Atlanta, GA, Jan, 8-10, 743-8

12. Sadegh Amalnik, Morteza (1994). Integrated Product Development at Design and Manufacturing, Company, National and International level Based on Computer Based System and Concurrent Engineering. Proc. 4^th Int. Conf. On Factory 2000,IEE, University of York, Oct.1994,pp.349-356.

13. Sadegh Amalnik, Morteza (1996). An intelligent concurrent advisory and manufacturability evaluation system for conventional and unconventional processes for improved product design. Paisly University, Paisly, Scotland

14. Sadegh Amalnik Morteza and Sadegh Amalnik Mohsen (2001). An Intelligent Concurrent Advisory and Manufacturability Evaluation System for Ultrasonic Machining. Computer and Industrial Engineering Conf., Canada

15. Sadegh Amalnik, Morteza, El-Hofy H. &. McGeough, J.A.(1997), Intelligent Concurrent Knowledge Based System for Electrodischarge texturing of Steel Rolls, Proc. 32^nd Int. Conf. Machine Tool Design Research (MATADOR) conf., Manchester, U.K.pp 419-424

16. Sadegh Amalnik Morteza and Sadegh Amalnik Mohammad.(2000), Intelligent Knowledge Based System for electrodischarge texturing. utomation Intelligent Manufact. Conf., University of Maryland, Maryland, USA, 2000

17. Sadegh Amalnik Morteza and. McGeough, J.A.(1996), Intelligent Concurrent Manufacturability Evaluation of Design for Electrochemical Machining. Journal of Material Processing Technology, 1996