PRODUCT DEVELOPMENT SUPPORTED BY THE SOFTWARE SYSTEMS OF THE UNIVERSAL PURPOSE

Product design process is one evolution process which depends of the development product way, from starting requirement to final solution. Table 1. Presence of the advanced technologies PRODUCT DEVELOPMENT SUPPORTED BY THE SOFTWARE SYSTEMS OF THE UNIVERSAL PURPOSE Slobodan NAVALUŠIĆ Milan ZELJKOVIĆ Zoran MILOJEVIĆ Advanced technology presence % Computer aided design) 80 Production and planning system 59 Flexible manufacturing systems (FMS/FMC) 38 Computer aided manufacturing 80 Robots (tool and material handling) 10 Automated transport system 13 Automated warehousing 8 Remote engineering 6 Remote service, maintenance 9 Electronic data exchange with suppliers 9 Electronic data exchange with clients 9 Abstract: In the introductory part of the paper, based on the available literature information and lasting many years experience, a review of the previous results, analysis of the current state, and estimation of the future development directions of the CA systems are given. In addition, some results of the up-to-date software systems usage in the process of the product development are shown. These results encompass not only product design phase but modular design, engineering analysis and virtual manufacturing phase in the product devolpment process. Key words: Computer Aided System, Product Development 1. INTRODUCTION Since theirs appearance, in early sixty years of last century, CAD/CAM technologies had a great influence on the product development in industry, which increased from year to year. Over 75% production companies in USA and more than 80% companies in Germany, which is leading economic power of united Europe, use CAD/CAM technologies [16]. It is the fact that is considered that CAD/CAM technologies are the biggest engineering accomplishment in 20 th century. Introducing of the advanced technologies in the industry represented significant factor which stimulated investment activities in the industry. Presence of the advanced technologies in European production companies is shown in the Table 1 [16]. From Table 1 it can be concluded that a large number of engineering activities, in process of product design, are covered by using of different CA systems. Certainly, in the future, these systems will be replaced by some more advanced systems. Mostly is expected of more important communication with suppliers and clients and maintenance and service efficiency increasing. 2. STRUCTURE OF ACTIVITIES IN THE PRODUCT DESIGN PROCESS Successful design process requires a lot of experience and knowledge, in certain scientific field, for appropriate solution generation for given project task. Design theory, which should provide support to the solution generation process, requires using of the independent design knowledge for given project task solving. Based on previous it can be concluded [11], [4]. In different fields exists knowledge about project solutions which could be added to specific task (or problem) Complex tasks can be decomposed into partial tasks. Approach to the independent knowledge field results from the similar project task. Knowledge from one field can be applied and used in some other field. For example, if for some problem from technology field does not exist appropriate solution, then should be possible to find similar problem or task in some other field (for ex. biotechnology) with existent solution which can be adapted to requested solution in technology field. Design, as a single task solving process, in general is defined as a system of operations [11]. Appropriate design plan structure depends of appropriate phase in the design process and design task class. In general approach, structure of the possible activities is taken as a starting point for appropriate design plan model. Design activities can be categorized and surveyed from two viewpoints (Figure 1) [11], [4]: hierarchy of complexity - every activity at one level contains the activities at the next, lower level, and is simultaneously contained in every activity at the next higher level. activity blocks - some activities are repeatedly applied in a certain (flexible) sequence. The activities from lower levels of complexity are nowadays relatively well and widely computer supported. 417

Fig. 1. Structure of the possible activities in the design process /10/ Computer based support for operations from lower levels usually includes execution of several various software tools (for example, elements of CAD systems, databases, numerical calculations, etc.). The model for computer-based support of activities at higher levels can be built from blocks of activities from lower levels. Because of that basic role of the design plan is - integration of the computer supported from lower levels, forming the blocks for building a support for higher level activities. Design plan, in addition to everything else, should provide mechanisms for control of the design process and data exchange between different types of the software tools. Design process prosperity from starting task to final design goal is controlled by design decisions and by application of the design constraints. Design decisions and constraints, because of that, should represent basic management structure in the design plan. 3. FORMER RESULTS A new era in development of the CA technologies started in the early 1970s with the introduction of solid modeling. CAD systems have been implemented on the minicomputers, while designers used graphic terminals for modeling and part drawing. An important event, the development of the microprocessor, announced era of the CA software based on the relatively low-cost PC platform. CAD part modeling and documentation software, with many of the functions found on the mainframe systems, was now available to individual designers, while design process got absolutely new dimension. While the PC-based systems were capable of performing many of the required design tasks, some operations required computing capability not present in the PC. A third CA system platform - RISC (reduced instruction set computer), was introduced in the early 1980s to meet this need. This systems has been called engineering workstations. In 1990s appeared NT operating system which became the de facto standard for PC industrial software development. An indisputable fact is that, until now developed CA systems caused a revolution in the product development. Nevertheless these systems do not support, on adequate way, modern requirements in the product design. Design, in principle, requires decisions which are made based on the certain number of the, not at all, perfect alternatives. During making these decisions, designers, very often, feel a need for addition of theirs logic reasoning with intuitive feeling about problem. Mentioned leads to new creative solutions and new knowledge. As a rule, this new knowledge can not be derived from existing, available knowledge and its evaluating is possible only after finding and testing of the appropriate 418

solution. Products complexity increase, their development become more complicated. Existing software tools are not possible to cover a wide spectrum of the activities connected to product development. Also, information volume, which during product development should be processed, is significant increased. Because of that ability to receive additional set of the new information, on effective and formal way, became very significant. 4. CURRENT STATE Intensive development of the computer hardware caused a significant decrease of their cost and increase of the possibility for their use with different CA tools to help designers to increase productivity and decrease needed time for design process. It could be mentioned tools for finite element analysis, mechanisms analysis, simulation etc. Existing of the mentioned software tools became driving force for development of the concurrent engineering concept which, today, presents standard in modern approach to product design process [5]. One of the basic concurrent engineering goals is building of the intelligent CAD systems which contain necessary technological information. In such systems an automated technological analysis (process which means analysis of the possible production - technological problem) is expected. This approach enables designer to focus only to creative aspect of the design process. It is evident that the problem of the technological analysis requires intensive geometric reasoning. The limited architecture of the earlier developed CAD systems and systems for solid modeling did not allow easy access and manipulation of the geometric and topographic entities, so there were no possibilities for significant geometric reasoning. This fact limits theirs capacities in the manipulation with complex design shapes. In the present time, functional capabilities of the commercial software packages and systems are significantly improved. This improving, connected to appearance of the systems with parametric design possibility (CATIA, ProENGINEER), and an open architecture of the systems for solid modeling make conditions for implementation of the techniques for complex geometric reasoning and integration of the systems which requires real technological analysis. Basic direction of the present CAD researching efforts is directed to the integration of the traditional CA tools on all levels of the product design process. In addition a review of the present trends in CA technologies is given [11]: Theoretical frameworks for "intelligent CA systems" are established. Languages based on logic and object oriented programming are developed. Also, integrated and intelligent environments which provide designers with the possibility to select items from a design catalogue in order to design custom parts are developed. Designed parts could be checked for manufacturability or some other criteria. Expert systems (ES) developed for this purpose are usually effective in the restrictive domains. Different approaches in the research of product data models consider integration of multiple computing processes, minimization of product development expenses, and appropriate database processing [11]. The fact that conventional CA systems are not well prepared to assist the engineer - designer in solving complex design problems enforces the research of integrated software environments. The development of design models based on the Artificial Intelligence has provided strong stimulus for current design research. Research that combine Artificial Intelligence and optimization methods have shown a significant impact on the formulation and solution of computational methods used in engineering design. Research in ES application suggest that standard ES approaches are of limited value for designing and planning. [11]. Aspiration to the integration of the geometric modeling and engineering analysis leads to the new engineering concept - virtual engineering. This concept provides a continual flow of the design process and engineering analysis cycle. Employing virtual technologies, designers can immerse themselves in a virtual environment, build components, modify components, operate devices and interact with virtual objects to perform design activities. 5. DIRECTIONS OF THE FUTURE CA SYSTEMS DEVELOPMENT Talking about future CA systems development it could be concluded the following fact. For future hardware development is very difficult to give some more serious estimation, because in this part of the CA technologies, recently, progress is the largest. In the software part basic research goal is development of the intelligent CA systems. These show analysis of the number scientific papers. Existing CA engineering tools are focused primarily around geometric CAD and analysis, with some tools supporting CAM activities such as process planning. Next generation systems will enable the capture of a broader variety of product information, and will support a wider range of product development activities than do existing tools [12]. The vision held by some for future product development tools is that of a "monolithic" software system [14]. In this vision, the product development process will be supported by a single integrated application suite. Such a tool would attempt to address the needs of the new product development paradigm, allowing teams that are potentially distributed geographically or across corporate boundaries to access tools and data at different phases of product development in order to produce a product. Some software vendors prefer working with a "business" models under which they establish relationships with other software companies and work to design interfaces between tools to make integration more seamless [15]. This philosophy has the potential to offer greater customization of software tool suites. The ideal next - generation systems for product development will be those with which individual companies, or teams involved in given product development activities, can collaborate using a heterogeneous set of software tools, and still exchange information and pass knowledge between various phases in the design process [15], [12]. 419

In any case, the next - generation CA systems should satisfied several basic principles [12]: System and designer should establish partnership. System should assist - help designer, not to replace him. System should provide appropriate collaboration and distribution. Design, as one complex process, involves many parties that collaborate from widely distributed geographical locations and utilize information resources that are equally dispersed. System should have an open architecture. The components of the system should be changed over time, through modification, replacement, deletion and extension depended of needs or new scientific achievements. System should be tool, not solution. The decision - support system should be designed as a set of tools rather than as solutions to a predetermined set of problems. System should have a high level internal representation. A high level representation of the real world objects that define the problem system forms the basis of the interaction between the users and the system and, also, the degree of intelligence that can be embedded in its components. System should have embedded knowledge. Knowledge can be described as experience derived from observation and interpretation of past events or phenomena, and the application of methods to past situations. Mentioned experience could be given in the form of rules, case studies, standard practices, and typical descriptions of objects and object systems that can serve as prototypes. System should have decentralized decision making. The decision - support system need not, and should not, exercise centralized control over the decision making environment. System should have appropriate computer - user interface. A high degree of interaction between designer(s) and the various components of the CA system is needed. In last time a theoretical establishing of the intelligent factories concept is developed. This concept means a system which can integrate basic production process segments in which is possible to increase manufacturability by using methods of the artificial intelligence. [1], [2]. Introducing of the artificial intelligence in these systems gives a high level of production process automation with significant increased flexibility. One of the researching directions has been directed to the development of the systems for automated gearbox design. Fig. 1. Model of the system for automated machine tools main drive gearbox design [9] First solution is based on the upgrading of the software package AutoCAD [10]. Similar solution is realized by upgrading of the system ME 10 [10]. The next approach to the problem of the gearbox design have been in comprehension of the mentioned process as an optimization process. Gearbox design, in this case, is treated as a mathematical interpretation of the gearbox and solution of the one multicriterion optimization problem. Last developed system is a system for automated machine tool main drive design [9], [10]. This system is developed based on the using of the expert systems. Expert part of the system is realized for conceptual design phase. On the Figure 1 a simplified flow chart of the mentioned system is shown. One of the development directions of the own automated design solutions, also, has been upgrading of the existing CA systems of the common purpose. Example for it is development of the system based on the AutoCAD system and ObjectARX development environment, Visual C++ 4.2 and MS Access 97. 6. EXAMPLES OF OWN RESEARCHING In the Laboratory for Machine Tools of the Faculty of Technical Sciences of Novi Sad researching connected to automation of the design process have been realizing for many years. First realized solution presents software system - SAPOR - S system for automated design of the technological process, control information - information for control of the NC machine tools for cutting processes [3]. Based on the experience acquired by development of the mentioned system, later are developed subsystems and systems for automation of the particular phases in the design process. Fig. 2. Communication beetwen ObjectARX and AutoCAD [6] 420

AutoCAD is realized as CAD system of the common purpose, and user can develop a special applications in AutoCAD development systems: AutoLISP, ADS or ObjectARX. The way of the communication between ObjectARX application and AutoCAD system is shown on the Figure 2 [7]. Based on the previously principle, module for NC verification is developed. NC verification software graphically simulates the material removal process by continuosly updating the solid stock shape as the cuter moves along the toolpath to produce the final part. NC verification enables following benefits: Detect NC program errors and bad or rapid cuts Machine parts corectly the first time Eliminate expensive and time consuming dry runs and proofing Reduce material scrap and overall cost There are two approaches in NC simulation and verification: exact and approximate approach [6], [8]. Model of the mentioned module - software solution, for the approximate approach, is shown on the Figure 3 [6]. System for modular machine tools design is developed based on the same principle. System is based on the existing module basis. Each module has defined a connected point which corresponds to the connected point of the other module with which connection is established. Example of one designed machine tool is shown on the Figure 4 [7]. System for automated modular machine tools design is, also, realized by using of the software package Mechanical Desktop 4.0 and supporting of the VBA (Visual Basic) language [13]. In this case automation of the modular design of the machine tool means computer aided design its main assemblies based on the available group of the modules and theirs composing by established logic of the modular design. On the Figure 5 a model of the system for automated design of the grinding machines is shown. An example of one designed machine tool (grinding machine tool) is shown on the Figure 6 [13]. Fig. 4. Example of the modular designed machine tool [6] In the engineering analysis field a system for automated design and behavior prediction of the machine tool main spindle is developed [17], [18]. Developed system enables automated design and prediction of the static, dynamic and thermal behavior of the machine tool main spindle assembly. Fig. 3. Model of the developed software solution Fig. 5. Model of the system for automated design of the grinding machines [12] 421

Input data for design Workpiece dimensions Maximal diameter 350 [mm] Minimal diameter 20 [mm] Maximal length 1000 [mm] Workpiece material Hardened steel No hardened steel Other characteristics Control Numerical Accuracy Normal Workpiece configuration Fig. 6. An example of one designed machine tool (grinding machine tool) [12] Fig. 7. Output analysis results of the main spindle assembly dynamic behavior [16], [17] 422

System is developed based on the enlarged technical beam theory (Timoschenko beam theory). It is concluded that modern solution of the main spindle assembly presents system with small uniform damping which can be, in the scope of this system, given in three ways: by coefficient of the relative damping, by Rayleigh proportional damping and by logarithmic damping decrement. The methodology is verified by experimental investigations comparing with results obtained by application of the software packages based on the finite element method (I-DEAS, ALGOR, SAP-90, ANSYS,...). An example of the output analysis results of the main spindle assembly dynamic behavior is given on the Figure. 7. 7. CONCLUSION Intensive technical - technological development causes need for new software tools generation in the product process development. In the paper authors give their own view of the present state and future expectations of the CA technologies. As is emphasized in the introduction part, represented analysiss of the prevous results, current state, and estimation of the future development directions of the CA systems are based on the available literature informaton and lasting many years experience of the authors in this scientific field. These analysis are necessary for balancing of the designer needs and existing technology with the market state and future plans. The direction of the own company development id defined by selection of the appropriate software tool for product development. It should be emphasized that, besides experimental - practical, in this field is necessary also an appropriate theoretical research work. It means researching in the development of the appropriate design models and theories. It is necessary to work on the universal design model - theory establishing through connection of the different scientific fields when this is possible. Instead of the future directions of the theoretical researching, we would like emphasize following remarks: It is necessary to develop design models - theories which will be applicable in practice. Form knowledge based on the experience which will be available for the future design procesesses. Make management of the design process easier - do not allow that this process significantly depends on the activity of the only one designer Make conditions that design process could be more efficacious, reliable and safe. Introduction of the CA systems in the process of the product development presents one of the greatest engineering achievement in the last century. Development of the information technologies and appropriate programming systems, which represent very significant support for designer during the design process, caused also a new way of thinking during design process. At the end of the paper, some results of the up-to-date software systems usage in the process of the product development are shown. These results encompass not only product design phase but modular design, engineering analysis and virtual manufacturing phase in the product devolpment process. It should be emphasized that these results are initial results for the future investigations. Mentioned results are carried out at the Institute of Production Engineering of the Faculty of Technical Sciences of Novi Sad. REFERENCES [1] GATALO, R., NAVALUSIC, S., ZELJKOVIC, M., TABAKOVIC, S.: Application of Artificial Intelligence in Product Design, Proceedings, 28 th Workshop of the Production Engineering, Faculty of Mechanical Engineering, Kraljevo, Serbia and Montenegro, 2000 (in Serbian). 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[7] MILOJEVIC, Z., ZELJKOVIC, M., GATALO, R., NAVALUSIC, S.: Automated Modular Design of the Machine Tools, Proceedings, XII Workshop on Supervising and Diagnostic of Machining Systems - Virtual Manufacturing, Karpacz, Poland, pp 187-194, 2001. [8] MILOJEVIĆ, Z., NAVALUŠIĆ, S., ZELJKOVIĆ, M (2006). An Exact Approach to 3-Axis Milling NC Simulation and Verification, Journal Manufacturing Engineering Vol.3, No.5, Kosicah, pp. 14-17. [9] NAVALUSIC, S., ZELJKOVIC, M., GATALO, R.: System for Automated Gearbox Design Based on the Principles of Expert System Building, Advancement of Intelligent Production, 7th ICPPE/4th ICHT, edited by Eiji Usui, Elsevier Science, B.V., pp 51-55, 1994. 423

[10] NAVALUSIC, S.: System for Automated Assembly Design in the scope of the Integral Concept of the Automated Products Design and theirs Technology, Ph. D. Thesis, Faculty of Technical Sciences, Novi Sad, Serbia and Montenegro, 1996 (in Serbian). [11] PAVKOVIĆ, N., MARJANOVIĆ, D. (2001): Considering an Object Oriented Approach to the Design Process Planning, International Journal Of Technology Management, 21/2001. [12] POHL, J., CHAPMAN, A,.: Computer-Aided Design Systems for 21st Century: Some Design Guidelines, www.cadrc.calpoly.edu/pdf/aided_design.pdf [13] POZAR, A., ZELJKOVIC, M., GATALO, R.: The Software Package for an Automated Modular Conceptual Design of Grinders, Proceedings, 4 th International Conference on Accomplishments of Electrical and Mechanical Industries - DEMI, Banja Luka, Bosnia and Hercegovina, pp 221-226, 2001. [14] REHG, J., A, KRAEBBER, H., W.: Computer- Integrated Manufacturing, Second edition, Prentice Hall, Upper Saddle River, New Jersey, Columbus, Ohio, 2001. [15] SZYKMAN S., FENVES S., KEIROUZ W., SHOOTER S.: A foundation for interoperability in next-generation product development systems, Elsevier, Computer Aided Design, No 33, 2001. [16] WENGEL J., GUNTER L. (2001); Contrasting Modernisation Strategies in Germany and the USA, Bulletin Innovation in Manufacturing survey, No 23. [17] ZELJKOVIC, M., GATALO, R. (1999): Experimental and Computer Aided Analysis of High - Speed Spindle Assembly Behavior, Annals of the CIRP, Vol. 48/1, pp 325-328. [18] ZELJKOVIC, M.: System for Automated Design and Behaviour Prediction of the Machine Tools Main Spindle Assembly, Ph. D. Thesis, Faculty of Technical Sciences, Novi Sad, Serbia and Montenegro, 1996 (in Serbian). The paper is a result of investigation on the project "Advancement of the system of technical preparation in the condition of the small batch production by using up to date software package of the universal application" No. 6330A, supported by Ministry of the science and life environment of the Republic of Serbia. CORRESPONDENCE Slobodan NAVALUSIC, Full Professor University of Novi Sad Faculty of Technical Sciences Trg Dositeja Obradovica 6 21000 Novi Sad, Serbia naval_sl@uns.ns.ac.yu Milan ZELJKOVIC, Full Professor University of Novi Sad Faculty of Technical Sciences Trg Dositeja Obradovica 6 21000 Novi Sad, Serbia milanz@uns.ns.ac.yu Zoran MILOJEVIC, Assistant, M.Sc. Eng. University of Novi Sad Faculty of Technical Sciences Trg Dositeja Obradovica 6 21000 Novi Sad, Serbia zormil@uns.ns.ac.yu 424