Reconfigurable Manufacturing Systems and Transformable Factories

In recent decades globalization has become a topic of utmost importance. Whilst world gross domestic product (GDP) grew at a compounded annual growth rate (CAGR) of 5.1% over the last 50 years, international trade has outmatched this trend with a CAGR of 7.7%.

European manufacturers have a high standard and a strong position in the industrial engineering with innovative and customized solutions. But they lose market share in mass production. Fig. 1 illustrates this migration process from centers of the Triade to developing and undeveloped countries. Both consumption and production of technical goods migrate to developing countries. Global markets, global logistics, global finance, and global distribution of knowledge accelerate the migration process.

At the end of the 20th Century, manufacturing entered a new era in which all manufacturing enterprises must compete in a global economy. Global competition increases customers’ purchasing power, which, in turn, drives frequent introduction of new products and causes large fluctuations in product demand.

Imponderabilities characterize the contemporary market developments, and most of them are beyond the influence of the producers [7]. They account for 20–30% of the production planning at present, and future increases cannot be excluded. The annual changes in the percentage of the registrations of petrol-powered and diesel-powered vehicles in Germany give an example (Fig. 1).

Since the introduction in 1995 one of the world’s first agile production system by Hüller Hille, this new production concept has gained increasing acceptance. Agile production is characterized by a series of operations or cells, each with multiple machines for parallel part processing. In most cases today, one and two spindle CNC machining centers perform the complete processing of complex workpieces, e.g., cylinder blocks, cylinder heads and transmission cases.

Increasing market competitiveness, frequent product upgrades, and changes in product demand have been the catalyst for the development of cost-effective manufacturing systems that can respond quickly to changes. Traditional Dedicated Manufacturing Systems (DMSs) are designed for a small range of production requirements and, while their performance is inherently robust, DMSs do not provide the required responsiveness. Flexible Manufacturing Systems (FMSs) are designed for a broad range of production requirements. However, while these systems are inherently responsive, FMSs are often more complex than required and, thus, their performance is not as robust as DMSs and they are not costeffective for many applications (Mehrabi et al. 2000). The challenge of developing cost-effective, responsive manufacturing systems has driven the development of a new paradigm in manufacturing: the Reconfigurable Manufacturing System (RMS) (Bollinger et al. 1998; Koren et al. 1999; Mehrabi et al. 2000; Mehrabi et al. 2002). These systems are designed such that they posses customized flexibility, that is, they are designed for specific ranges of production requirements and can be cost-effectively converted when production requirements change. Thus, these systems are economical and robust since they are customized to the production requirements, their resources are minimized, and flexibility in their design allows for cost-effective conversion when new production requirements arise.

In today’s competitive markets, manufacturing systems must quickly respond to changing customer demands and ever-shorter product life cycles. Traditional transfer lines are designed for high volume production and operate in a fixed automation paradigm. They cannot, therefore, accommodate changes in the product design. On the other hand, conventional CNC-based “flexible” manufacturing systems may offer flexibility, but are generally slow and expensive because they are not optimized for any particular product or a family of products.

A common type of machine tool in durable goods manufacturing industries until recently was a dedicated machine tool (DMT). The roots of these machines go back to the early days of mass production in the automobile industry in the 1920’s. For the sake of operational efficiency, manufacturing process was divided into the smallest possible tasks and then carried out by specialized machines (stations). Since the machines were dedicated to a particular task, it was possible to employ hard automation, a key enabler in high-volume, low mix, and highly repetitive manufacturing. The dedicated machines still constitute majority of the legacy manufacturing systems, which continue to be in operation today.

The industrial needs to respond quickly to new product changeovers and fluctuating market demands have generated immense academic interests and research activities to develop a broad spectrum of reconfigurable manufacturing systems and technologies in the equipment (hardware), methodologies (software), and control modules (interfaces) arenas so as to produce the demanded volume of the desired product at the opportune time and at optimal costs [16, 17, 18]. The combined efforts of numerous research initiatives worldwide have made major strides in developing basic theories and paradigm-shift technology innovations as the building blocks of the science and engineering of reconfigurable manufacturing. Nevertheless, the development of agile or reconfigurable fixtures has not been one of the more popular mainstream focused research areas.

Diversity of variants, rising flexibility, reduction of time-to-market, mass customization, shorter product lifecycles are not only buzzwords but real facts which producing companies have to deal with day by day. One strategy in facing these challenges in the future is the use of Reconfigurable Manufacturing Systems (RMS).

The absolute positioning accuracy of a motion control system is, making abstraction of errors induced by imperfections of the transmission, completely determined by the positioning accuracy of the individual actuators. Accurate contouring additionally requires high degrees of synchronisation between actuators. Indeed, the superposition of two orthogonal and sinusoidal movements only results in a perfect circle if both have exactly the same frequency and if they are out of phase by exactly ninety degrees.

As we adopt new manufacturing concepts, such as Reconfigurable Manufacturing Systems (RMSes), we must also ask where it is best to use them and how best to use them. Accordingly, we must adapt our design, modelling, and measurement techniques.

Today’s manufacturing industry is in very tough global competition. Manufacturing system, which is one of the very important factors to make manufacturing industry more competitive, is keenly required to solve the following issues.

To date, automation has been most successfully used in mass production applications. In such environments, custom automation systems are designed to meet the specific process and production volume requirements of a given product or a predefined family of products. These conventional automated manufacturing systems development efforts generally lead to the most efficient production system and represent an ideal strategy for high volume production where the cost of the dedicated system can be recouped over the market life of the supported product set. However, custom automation systems are similar to jigsaw puzzles in that their component technologies can only fit together in a specific manner and cannot be easily reused for additional applications. The high degree of system customization which make these systems so highly efficient and cost effective for a target product frequently precludes its cost-effective redeployment for any other product.

Computer supported decision making system that generates and optimizes layouts of reconfigurable manufacturing equipment at the early stage of design is described here. Complicated machine units, for example, engines, consist of a great number of parts. For making each part it is necessary to create a production system consisting of several technological machines.

The most cost-effective solution for the production of numerous uniform product series under specific economic considerations is the product-specific series machine. However, the aspect of flexibility of the machine tool becomes more and more important as the variety of alternatives increases and product life cycles decrease [7]. As a result, development trends move from product specific machine tools towards stand-alone machines overlapping the product life cycle. Reconfigurable Multi Technology Machine (RMM) fulfills these requirements. The RMM is characterized by a very high degree of modularity and flexibility. Its universality is accomplished through a consistent design of the machine according to the modular concept, rather than covering all necessary options. This means that the technology modules are either added on or left out of the reconfigurable machine tool with the help of largely standardized interfaces.

In order to cope with changes in demand and to maintain high efficiency in cellular manufacturing (CM) systems, this paper considers two methodologies; designing flexible cells and cell redesign based on demand at each period. These two methodologies are formulated mathematically. The solution method using the genetic algorithm (GA) is proposed by numerical experiments and the performance of the proposed methodologies is analyzed and compared with each other.

The Japanese industry is now in need of production systems for that can handle variation, small quantities, and short lead-times. Such systems have to meet various customer-dependent, produce particular product variants in small quantities to reduce stock of finished products, and have short lead-times to quickly push new models from design to shipment. Those that require this type of production systems are large corporations, with annual sales in the billions of US dollars, which produce consumer products like automobiles, cellular phones, or LCD televisions. Also mid-sized market players have similar needs: companies with annual sales on the order of tens of million dollars, that produce electronic parts, mechanical modules, housing and so on. These companies must always have their production lines capable of change, irrelevant of the sales. This is because the mentioned consumer products and mid-way parts see the production peak, immediately before the product release and drop to a fraction within half a year.

Companies in processing industries operate today in a turbulent environment. The turbulence is mainly caused by innovative technologies, the customization, and the permanent change throughout the various supply sectors. Companies can develop effective survival strategies only if they are able to continuously adapt their organizational structures [8, 12].

If we look at the evolution steps of factories in the last 20 years, we basically find different factory concepts and production concepts in every decade depending on different goals and criteria (Fig. 1).

This chapter offers a look at the automotive manufacturing processes in use today and how these processes may look in the near future. The focus is on the manufacturing process itself and its impact on the factory structure, beginning with equipment, which should be reconfigurable (see parts II, V of this book) in order to facilitate faster and more cost-effective car model changes, and continuing with the factory itself, which should posses a kind of transformability of its structure and layout.

With increasing product and process complexity and with advancing globalization, cross-company assessment and standardized optimization of procurement, production and sales processes are becoming increasingly important. Using innovative methods and technologies, continuous logistics processes in the form of supply chain management (SCM) will in the future become a key success factor in ensuring the global competitiveness of companies in the automotive industry

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. Given over 70% external share in value added and rising customer orientation, vehicle manufacturers and their suppliers need to confront the new tasks and challenges by leveraging the supply chain collaboration (SCC). The crucial competitive element is now the efficiency and flexibility in the supply chains and networks taken as a whole, rather than in one individual company

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The factory of the future can be characterized by greater global competition, higher product variety and lower product volume. Higher product variety, faster product development and shorter product life cycle complicate the demand forecasts and subsequent manufacturing processes. Product cost and product quality have been classically considered as the main objectives for obtaining competitive advantages of a manufacturing system. Currently, merely assuring low cost and high quality of products is insufficient for obtaining competitive advantages of a firm. New requirements such as product customization and production responsiveness should be taken into account for the survival in the competitive environment and the growth in the market share.

The basis for development of the world today is the creation and persistent improvement of various kinds of the systems securing the vital activity of people. In particular, these are referred to the complicated technical systems of road vehicles making a great influence on all aspects of a humane life. The complex of operating parameters of the vehicles not only determines the speed comfort and safety of travel. It affects also the global problems, such as environmental ecology power consumption and many others.

Recent years brought us a considerable improvement of fuel efficiency and decrease of the automobile engine exhaust gas toxicity. Leading automobile makers compete with the legislators each other to attract customers and are forced to upgrade engines using latest design and manufacturing solutions.

Time required for making prototypes of automobiles, engines, transmissions and other components becomes crucial for staying competitive in the modern automobile industry. Development of the Rapid Prototyping (RP) technology, based on 3D computer modelling has revolutionized the design processes. RP opens possibility to materialize CAD data by using CAM (Computer-Aided Manufacturing) techniques. The advantage of the new technology is its ability to store complete digital information describing an object and use it to create a physical prototype. Today almost all automotive companies widely use RP method, but the fastest development takes place in the field of test sample making. RP greatly shortens the time between development and production phases and thus provides a key advantage in competition despite relatively high cost of the required special equipment.

In modern machine-building the problem of creating highly-efficient technological mechanical machining processes, taking into account the energy and resourcessaving and ecological requirements is one of the paramount importance.

To adapt and adjust the existing manufacturing systems to fluctuating requirements of product demand and variety, flexibility has to be raised to new levels over what was usually provided in the past. The primary issue then is to how to define and implement such flexibility, to ensure changes of the machining systems in accordance with the completely new, non-predictable machining tasks required for new products.

Industrial application of lasers, particularly in machine-building and in precise instrument- making industry, is constantly expanding due to unique power – and physical and mechanical properties of optical quantum generators and technological processes on their basis [1].

In the current market, demand from the customers varies to the highest degree. Consequently, manufacturers need to determine some new approaches that can lead to achieving higher production rates and/or reduce the production costs. In the past production systems, the facility layout, workers’ assignment and the function of each machine were held constant. Recently, Reconfigurable Manufacturing System (RMS) [1], a production system that allows the modification of the system configuration, such as facility layout, workers’ assignment and machine function, emerges. The improved efficiency of RMS to deal with the various demands from the customers can be expected.

Dedicated manufacturing lines (DML), flexible manufacturing systems (FMS) and reconfigurable manufacturing systems (RMS) are, nowadays, the three production paradigms representing three ways of thinking and implementing production systems. Nevertheless, very few researches aim at clearly defining the convenience of such three manufacturing paradigms with regards to the market and competition characteristics in which the company plans to play. This chapter goes toward such a direction; in particular, an investment model for each kind of manufacturing system (DML, FMS, RMS) is proposed; these models are able to consider several market and competition issues such as product demand dynamic over the investment period, the possibility of several production mix composition, products direct costs and prices and so forth. The comparison of the manufacturing system configurations coming out from the optimization of the proposed models, allows to build up a general understanding about the field of economic convenience of each manufacturing system typology.

As markets mature, they become increasingly global in nature, and companies find themselves competing with companies in many different parts of the world, which are subjectto different laws and have different intellectual and natural resources. This makes the need for continuously updating and improving products a major factor for successful companies.

Dedicated Manufacturing Systems (DMS), Adjustable Manufacturing Systems (AMS), Flexible Manufacturing Systems (FMS) are the three basic types of manufacturing systems commonly used in manufacturing industries, while Reconfigurable Manufacturing Systems (RMS) is considered as the future of manufacturing systems. In this paper we will give an analytical and qualitative comparison among DMS, AMS, FMS and RMS from the viewpoint of cost, adaptability, complexity, production rate and ramp-up time.

Market globalization and aggressive economic competition are driving a trend in manufacturing toward the adoption of flexibility features in order to better react to changes related to customer needs, process technologies, government directives, etc. Wide-ranging research efforts have been carried out in order to understand which of these flexibility features are critical in achieving the particular business tasks and how or when to implement them. Flexibility can be purchased through special features in capital equipment, and it can take a form of flexible manufacturing equipment, options to change the product mix, and the opportunity to temporarily shut down and restart production systems. Flexibility also includes options to switch production across various plant locations, depending on labor conditions, demand and currency fluctuations. Therefore, flexibility allows the management to take advantage of the outcomes better than expected and at the same time to reduce the losses. This capability must add a value to the investment project having such embedded options. (Bengtsson 2001).

The development of technologies, particularly in the domains of information and communications, offers us fascinating possibilities for new products that can help create new jobs and greater prosperity. Such promise is essential for mechanical engineering and related sectors like the automotive industry.

Nowadays, most mechanical engineering products already rely on the close interaction of mechanics, electronics, control engineering and software engineering which is aptly expressed by the term mechatronics. The ambition of mechatronics is to optimize the behavior of a technical system. Sensors collect information about the environment and the system itself. The system utilizes this information to derive optimal reactions. Future mechanical engineering systems will consist of configurations of system elements with inherent partial intelligence. The behavior of the overall system is characterized by the communication and cooperation between these intelligent system elements. From the point of view of information technology we consider these distributed systems to be cooperative agents. This opens up fascinating possibilities for designing tomorrow’s mechanical engineering products [1]. The term self-optimization characterizes this perspective.

Products and manufacturing systems from mechanical engineering and its related industrial sectors like automotive engineering are getting more and more complex. Time to market is decreasing simultaneously. Under these circumstances the product creation process is facing extraordinary requirements. The product creation process ranges from the initial product idea to a successful entry into market. The whole process covers three major steps. These are strategic planning, product development and development of production systems.