رویکرد یکپارچه طراحی سیستم های تولید انعطاف پذیر

The paper presents a holistic methodological approach for designing flexible production systems, integrating the management of the production resources, operations planning, internal logistics and quality. The proposed methodology relies on lean principles and encompasses a series of stages and tools that may be used to design and to assess the robustness of the production system for tackling small series and frequent changes in the productive processes due to customized production. This approach has been applied to the redesign of the production system of a Portuguese machinery manufacturing industrial company. Results show that it effectively led to a new flexible production system and a new industrial layout capable of responding to diverse future scenarios of products demand.

The efficient design of flexible production systems to tackle customized products in small series is key for increasing competitiveness [1]. A current business trend is to offer a larger number of products with a higher level of customization, according to the costumer requests, produced under strict quality requirements, and with shorter production lead times. Consequently, the production systems with origin in the shop floor [2] need to be designed in a flexible way in order to cope with the frequent changes in the productive processes that affect the type and sequence of operations to be performed. For this purpose, polyvalent production equipment needs to be managed in order to reduce the setups. The physical arrangement of the equipment in the layout should minimize the need to transport the materials between consecutive operations. New flexible and dynamic internal logistics infrastructures are further needed for dealing with rapid and safe materials movements.The literature review shows that Lean Manufacturing principles and tools are becoming quite popular for improving production systems by eliminating the expenditure of resources that do not contribute directly for creating value as perceived by the customer (e.g.[3]). In particular the practitioner-oriented literature presents many real-world cases where lean tools were applied to improve some of the aspects of flexible production systems design such as capacity planning, operations management, industrial layout design and internal logistics design. The application areas are quite diverse (ranging from industrial sectors like automotive, aircraft to services like and waste recycling (e.g. [4] to[7]), empirically-driven and affected by many casespecific factors (including cultural, technological and industrial differences). Proper methodologies for lean implementations are still under debate in practitioners and scientific communities and holistic approaches are rarely found.Some authors [8], [9] propose methodologies based on the Systems-of-Systems theory for adopting the lean principles in a systemic perspective. Other authors [10] use an axiomatic design-decomposition methodology for designing the whole production process taking into account the system and design objectives s well as their relations. Still others (e.g. [11] to [13]) emphasize the need to develop indicators and provide measures of the lean production. Further holistic approaches are needed to extend lean principles and creating synergies among the interrelated aspects of production systems design. In fact, the characteristics of an industrial layout may pose constraints to operations planning and equipment physical location, while improvements in the layout and the logistics infrastructure may emerge from a more flexible planning of the production operations. Furthermore, a common diagnosis of the current status of the production system may lead to a more detailed blueprint and help to save time avoiding repetitive data gathering processes.This paper presents a lean-based holistic methodological approach for designing flexible production systems, integrating all relevant components, including the management of the production resources, operations planning and scheduling, and internal logistics.The paper starts by describing the methodology for integrated design of production systems. The focus will be in describing the main stages of the methodology together with the set of tools that may be used to support each stage. The paper will further describe the application of this methodological approach to redesign the production system of a Portuguese machinery manufacturing industrial company. Brief insights about the organization of the project for designing production systems in collaboration with the practitioners of the industrial company are further discussed.

The integrated methodological approach proposed in this work addresses all the components of production systems, including operations planning and scheduling, defining the layout of the production equipment, and sizing the logistics infrastructure. This approach and the developed tools, some of them driven from lean techniques, seems to be adequate for designing and assessing new flexible production systems to tackle small series and highly customized products. Future work will improve this methodological approach through the development of robust web tools built based on the PsCap and PsFlow software. Additional work will disseminate this approach in consultancy companies and look for its continuous improvement and wider application in many industrial sectors.