Reconfigurable Manufacturing Systems: From Design to Implementation

The reconfigurable manufacturing system (RMS) was introduced in the last decade of the twentieth century as a novel engineering response to volatile global markets that instigated large uncertainty in product demand. Today, most automotive engines and powertrain components in Europe and in the USA are produced on RMS. The RMS has matrix-type system architecture and contains CNC machines arranged in operational stages and in-line inspection machines. To enable the rapid responsiveness, the RMS possesses six characteristics: scalability, convertibility, diagnosability, modularity, integrability and customization. This chapter discusses the emergence of reconfigurable manufacturing systems (RMSs).

Flexibility is a complex concept, difficult to define. Most of the definitions of flexibility refer to the adaptation of the system in a changing context, which is quite general. We propose to see flexibility as a black box, without trying to define how the system works internally. This external point of view allows most of the parameters, which influence flexibility to be identified. Our definition of flexibility highlights customer satisfaction, changes in demand and in the environment in order to remain competitive. Each of the terms of this definition is studied. We propose a typology of companies in terms of flexibility, and we show why reconfigurable manufacturing systems are often the solution for companies that need to combine flexibility and productivity. We develop the eight characteristics of RMS. Among these eight characteristics, we propose a new one: reconfiguration strategy that enables to choose the best way to adapt the system to changes. Finally, we discuss an approach based on an eight-dimensional Kiviat to classify RMS.

Nowadays, the market is characterized by a high level of competitiveness and very frequent and sudden variations within the production context. The critical review of the existing manufacturing paradigms, which are the dedicated manufacturing lines (DMLs) and the flexible manufacturing systems (FMSs), reveals that these systems are not capable of fulfilling the requirements imposed by the current market; these requirements are mainly resumed in cost, quality and reactivity. Therefore, the need for a new manufacturing paradigm that could fulfil these requirements has arisen. Reconfigurable manufacturing system or RMS is this new paradigm; it is supposed to be reactive enough to cope with the sudden changes in the market while keeping the products’ quality high at a low cost. The main challenge in RMS is their design. Most of the suggested methods in the literature do not address the RMS design issue as a whole; they treat just a part of the problem. Hence, as a contribution, we propose in this chapter, a generic RMS design methodology based on systems engineering (SE). This methodology will support the RMS design along the development process. It is based specifically on the standard ISO/IEC/IEEE15288, which is the most recent standard in SE discipline.

This chapter is dealing with the design of the architecture and physical configuration of a reconfigurable machine tool (RMT) as well as reconfigurable manufacturing system (RMS) based on modelling and tools which allow describing functional modules, machines, parts and process plans. The relevant parameters for the purpose are defined and can be used in the frame of a methodology based on a parsimony approach, so several configurations are obtained and after that used for designing the optimized final system by taking into account of logistical and economic constraints linked to the products to be manufacture. So, the product family which can be manufactured on the system is defined and it will be easy to know if a new product can be manufactured on the system or it will necessary to change the system confirmation. The methodology for designing production system is mainly based on a homogeneous matrix for describing the machine structure and manufacturing features for describing parts in terms of geometrical data. The technological knowledge is formalized into the features and the rules used for process plan generation. After that, the models can be used for geometrical and kinematic simulation which allows getting a 3D model of the system and the geometric quality expected.

Reconfigurable machine tools (RMT) are crucial for the realization of reconfigurable manufacturing systems (RMS). Hence, the intelligentization of the manufacturing sector hinges on the reconfigurability of RMTs, and the key to achieving RMT reconfigurability lies in the formulation of an effective approach for the design and selection of RMT configurations. In this work, a modular approach to RMT design and configuration selection was proposed to address the problems of RMT configuration design. A detailed study was performed on the fundamental theoretical aspects and key technologies that concern RMT design, which include machining targets, module selection, configuration expressions and configuration selection. The proposed method may be summarized as follows: first, operation identification, planning and merging are performed according to the machining target’s features. Based on the known operations, the functions and structures required for RMT are determined and subsequently mapped to a series of mechanical modules and RMT configurations. Based on the generated RMT configurations, feasible candidate solutions are selected according to a number of key metrics. Finally, a preference ranking algorithm is used to rank the candidate solutions and select the most appropriate configuration.

In the recent years, the adoption of reconfigurable systems represents a primary strategy to improving flexibility, elasticity and efficiency in both manufacturing and assembly. Global markets, the increasing need for customization, high-quality standards, dynamic batches and short life cycles are the key factors driving the transition from traditional to reconfigurable manufacturing systems (RMSs). Despite their automation level, such systems still require actions by human operators, e.g. material handling, WIP load/unload, tool setup, etc. These operations rise safety issues because of the human–machine interaction and cooperation. Particularly, RMSs require changes of auxiliary modules and tools, based on the manual intervention, to achieve effective system configurations enlarging the produced mix. In this field, embracing the emerging Industry 4.0 technology, a lack of procedures and reference approaches exists to supporting companies and practitioners in analysing the impact on safety and ergonomics coming from the switch from standard to RMSs. This chapter, after revising the literature, standards and reference guidelines, converges to an innovative methodological and operative framework supporting and spreading the integration of safety, ergonomics and human factors in the emerging reconfigurable systems. Deep attention is paid to best-in-class examples, from industry, to strengthen the industrial perspective and applicability.

Scalability is one of the characteristics of reconfigurable manufacturing systems, which aim to adapt the production capacity, quickly, efficiently and cost-effectively. Our goal in this chapter is to propose a global analysis of all configurations possible for a system on the point of view of scalability. For a fixed balancing of operations on the stages of the production system, we propose new metrics to evaluate the scalability of reconfigurable manufacturing systems by considering all configurations that can be obtained. These metrics rely on two main characteristics of the systems: the takt time and the number of resources of the system. We show how it is possible to adapt multi-objective metrics to this context, considering the two characteristics as multi-objective criteria. We want to evaluate the pertinence of classical balancing methods to design scalable systems.

Nowadays, in a hotly competitive environment, companies are facing numerous challenges. Indeed, to be relevant, the manufacturing system of a company must be, simultaneously, cost and time-efficient and environmentally harmless. Moreover, due to the escalation in fuel prices, higher tariff for electrical use and environmental legislations, the reduction in energy consumption and carbon footprint has become the need of the hour in the manufacturing sector. Thus, reconfigurable manufacturing system (RMS) is proposed to cope with these new challenges. It is considered as an enabler for Industry 4.0 due to its core characteristics, namely scalability, convertibility, diagnosability, customization, modularity and integrability. In this chapter, we consider the multi-objective single-product process plan generation problem in a reconfigurable manufacturing environment where in addition to the total completion time and total production cost minimization, total energy consumption is minimized. First, a multi-objective mixed-linear integer programming model is proposed. Moreover, an augmented ε-constraint-based approach is developed to solve the model. Finally, to show the applicability of our approach, an illustrative numerical example is proposed.

Reconfigurable manufacturing systems are not only new manufacturing paradigm offering a customized flexibility. They are also a basis to develop new generation of sustainable production systems. A promising way toward the sustainable production passes through the design and intensive development of reconfigurable manufacturing systems. The objective is to increase the life cycle, take into account the end of life and to decrease the energy consumption and gas emissions. In this chapter, the state of the art is analyzed from this perspective and five new avenues of research are proposed.

The problem of reconfiguration appears also for the transfer lines that are designed for mass production of a single product. When a new product should be produced at an existing transfer line, it is necessary to reconfigure it. This is costly, and thus, the reconfiguration process should be optimized. This chapter presents a multi-objective mathematical model for such a problem and develops a goal programming approach to solve it. The results of computational experiments are reported.

Reconfigurable manufacturing systems possess the advantages of being both rapidly responsive to changes in products and demand, as well as being cost-effective in terms of productivity and system lifetime extension. Based on the design principles of modularity, integrability, customization, and diagnosability, rapid reconfiguration of functionality and capacity can be accomplished on various system levels from equipment level to complete factories, in order to respond specifically to company-specific drivers and requirements of change. Therefore, reconfigurability can be designed to appear in a vast array of forms when implemented in practice, in order to provide company-specific responsiveness to change and contribute to increase manufacturing competitiveness. In this chapter, insights from eight case studies conducted in manufacturing companies transitioning towards reconfigurability is presented, with particular focus on drivers of reconfigurability, expected potentials, and on how the appropriate reconfigurable system concept is designed in accordance, covering structuring level, enablers, and their realization. Through these case studies, a diversity of reconfigurability applications are identified and compared, which leads to propositions on generic aspects of reconfigurability applications in practice linked to company characteristics. Thus, the chapter not only contributes with knowledge of industrial applications of reconfigurability, but also addresses reconfigurability as a multifaceted capability that needs to be designed and tailored to suit the specific company and its context, in order to be a key to increased manufacturing competitiveness.