A methodology to define a reconfigurable system architecture for a compact heat exchanger assembly machine

Due to the unexpected, fast, and constant changes of market requirements and the hypercompetency, robust manufacturing systems are needed that adjust easily to operational variability and the customized product supply. The simply substitution of components, software, hardware, and/or their adaptation by parameters resetting are an attractive option to face this challenge. Short product life cycles are an undeniable consequence and evidence of this. For this reason, to develop products or services profitably in the product manufacturing field, it is common to use the product family concept, which involves sharing components, functional features, and manufacturing process, both to make a cheaper product development process and to obtain customized products. A new generation of manufacturing systems that deploy characteristics such as adaptability and flexibility responding to the market dynamics called reconfigurable manufacturing systems (RMS) are required by market according to manufacturing experts. The manufacturing systems with modular architecture are the best way to meet flexible and adaptable RMSs because they allow reconfiguration by a simple module substitution or by resetting module operation parameters. This paper presents a design methodology developed to obtain modular RMS. The method integrates the utilization of modular architecture principles, selection algorithms (analytical hierarchical process), clustering algorithms (average linkage clustering algorithm), family product features and functional system analysis in the classical product design process. The methodology proposed allows defining the most adequate modular system architecture and the modular definition of the reconfiguration variables that are needed to reach the flexibility required. A real study case about a heat exchanger assembly machine is presented where this methodology is applied in order to present an evidence of its usefulness.     

Assessing the structural complexity of manufacturing systems configurations

Modern manufacturing systems are increasingly required to be flexible and adaptable to changing market demands, which adds to their structural and operational complexity. One of the major challenges at the early design stages is to select a manufacturing system configuration that both satisfies the production functional requirements and is easy to operate and manage. A new metric for assessing the structural complexity of manufacturing system configurations is presented in this paper. The proposed complexity metric incorporates the quantity of information using an entropy approach. It accounts for the complexity inherent in the various modules in the manufacturing system through the use of an index derived from a newly developed manufacturing systems classification code. The code captures the effect of various component types and technologies used in a manufacturing system on the system’s structural complexity. The presented metric would be helpful in selecting the least complex manufacturing system configuration that meets the requirements. An engine cylinder head production system is used to illustrate the application of the proposed methodology in comparing feasible but different manufacturing system configurations capable of producing the cylinder head based on their structurally inherent complexity.     

Social-technical aspects in modern manufacturing

Manufacturing companies are having to compete in a more and more global market. Continuous quality improvement, a reduction in product price and production series shortening have become necessary in order to be competitive. In such a situation, the development of production systems is necessary. This can only be done via the development of all manufacturing system elements such as production methods, machines, process, control and information systems. One important part of manufacturing systems that is very often not appreciated enough is the human being. This paper focuses on the changing role of managers and machine operators. Problems regarding quality of human decisions, artificial intelligence support and a socio-technical design approach are discussed as well. The aim of this paper is to present the important factors that significantly influence the balanced development of advanced manufacturing systems. The article is the result of a research project focused on improving the cooperation between machine operators and technical systems in manufacturing companies.     

A resource-based modelling approach to support responsive manufacturing systems

The manufacturing industry faces the challenge of responding quickly to the ever-changing requirements of customers. A key factor in these highly competitive environments is an ability for companies to master key production system dynamics such as change in the product types and variants and production quantities that they make, with high quality, low cost, and fast delivery. A novel approach to modelling manufacturing systems is introduced which is based on the provision of means for explicitly representing and computer executing dynamic producer units (DPUs). DPUs are defined as re-usable, change capable components of a manufacturing enterprise and have been described in the present authors’ previous publications. DPU concepts were conceived to support (1) the design of change capable manufacturing systems that can realise families of similar products in varying quantities and mixes and (2) the re-configuration of manufacturing systems in cases of withdrawal of a product family and introduction of a new one. To achieve this, a generic manufacturing system model is required to facilitate the systematic and timely alteration of production system designs and production plans. DPU modelling concepts facilitate these alterations through explicitly specifying the need for change capabilities so that rapid and cost-effective changeover responses can be made when production requirements change. This paper presents how DPU modelling concepts can be applied with reference to an industrial case study and describes a change decision-making framework in the form of a taxonomy and enabling tools.     

Investigating optimal capacity scalability scheduling in a reconfigurable manufacturing system

Responsiveness to dynamic market changes in a cost-effective manner is becoming a key success factor for any manufacturing system in today’s global economy. Reconfigurable manufacturing systems (RMSs) have been introduced to react quickly and effectively to such competitive market demands through modular and scalable design of the manufacturing system on the system level, as well as on the machine components’ level. This paper investigates how RMSs can manage their capacity scalability on the system level in a cost-effective manner. An approach for modeling capacity scalability is proposed, which, unlike earlier approaches, does not assume that the capacity scalability is simply a function of fixed increments of capacity units. Based on the model, a computer tool that utilizes a genetic algorithm optimization technique is developed. The tool aids the systems’ designers in deciding when to reconfigure the system in order to scale the capacity and by how much to scale it in order to meet the market demand in a cost-effective way. The results showed that, in terms of cost, the optimal capacity scalability schedules in an RMS are superior to both the exact demand capacity scalability approach and the approach of supplying all required capacity at the beginning of the planning period, which is adopted by flexible manufacturing systems (FMSs). The results also suggest that the cost-effective implementation of an RMS can be realized through decreasing the cost of reconfiguration of these new systems.     

Customer-focused and product-line-based manufacturing performance measurement

Until the 1980s, manufacturing companies relied solely on performance measurement systems based on traditional cost accounting systems to control, monitor, and improve operations. However, it has been shown that these systems do not capture the relevant performance issues for today’s manufacturing environment. Pre-80s systems focused on monitoring and controlling instead of supporting process improvements, promoting overall system optimization and addressing the dynamics of changing systems. A variety of integrated systems were proposed to overcome the limitations of the traditional performance measurements systems. However, these systems have not yet fully addressed the performance measurement system requirements for today’s manufacturing environment. This paper presents an integrated dynamic performance measurement system (IDPMS) developed in conjunction with the D Company Plant of Chungli, Taiwan. IDPMS integrates three main areas; company management, process improvement, and the factory shop floor. To achieve an integrated system, these three areas are linked through specifications, reporting and dynamic defined success area updating, performance measures, and performance standards. This study is undertaken to specify the interaction and movement among the three groups in the process from production planning to customer, “planning-manufacturing-customer”. The results from these stages, production planning, manufacturing, and customer service, are integrated. These factors are transformed into measurable, quantitative, and JIT (just-in-time) parameters utilized along with management by objectives (MBO) principles in planning and establishing a manufacturing performance measurement system focused on satisfying both internal and external customers. An example is given that illustrates how the IDPMS addresses the current performance measurement system requirements.     

Effect of reconfiguration costs on planning for capacity scalability in reconfigurable manufacturing systems

In a globally competitive market for products, manufacturers are faced with an increasing need to improve their flexibility, reliability, and responsiveness to meet the demands of their customers. Reconfigurable manufacturing systems (RMS) have become an important manufacturing paradigm, because they broadly encompass the ability to react efficiently to this environment by providing the exact capacity and functionality needed when needed. This paper studies how such new systems can manage their capacity scalability planning in a cost effective manner. An approach for modeling capacity scalability planning is proposed. The development of the model is based on set theory and the regeneration point theorem which is mapped to the reconfigurable manufacturing paradigm as the capacity scalability points of that system. The cost function of the model incorporates both the physical capacity cost based on capacity size and costs associated with the reconfiguration process which referred to as the scalability penalty cost and scalability effort cost. A dynamic programming (DP) approach is manipulated for the development of optimal capacity scalability plans. The effect of the reconfiguration costs on the capacity scalability planning horizon and overall cost is investigated. The results showed the relation between deciding on the optimal capacity scalability planning horizon and the different reconfiguration costs. Results also highlighted the fact that decreasing costs of reconfiguration will lead to cost effective implementation of reconfigurable manufacturing systems.     

Reconfigurable manufacturing systems: Principles,design, and future trends

Reconfigurable manufacturing systems (RMSs), which possess the advantages of both dedicated serial lines and flexible manufacturing systems, were introduced in the mid-1990s to address the challenges initiated by globalization. The principal goal of an RMS is to enhance the responsiveness of manufacturing systems to unforeseen changes in product demand. RMSs are costeffective because they boost productivity, and increase the lifetime of the manufacturing system. Because of the many streams in which a product may be produced on an RMS, maintaining product precision in an RMS is a challenge. But the experience with RMS in the last 20 years indicates that product quality can be definitely maintained by inserting in-line inspection stations. In this paper, we formulate the design and operational principles for RMSs, and provide a state-of-the-art review of the design and operations methodologies of RMSs according to these principles. Finally, we propose future research directions, and deliberate on how recent intelligent manufacturing technologies may advance the design and operations of RMSs.     

e-制造系统的制造资源动态配置过程研究

传统制造资源动态配置没有涉及制造系统、制造单元和设备之间制造过程信息的重组模型,据此,在拓展传统制造资源动态配置模型的基础上,结合模糊聚类理论,研究了e制造环境下制造任务在一定批量和多工艺方案情形下的单元化配置模型,以及基于此配置结果的制造系统、动态制造单元、设备间的信息重组模型与制造过程信息跟踪方法,为“柔性制造”、“数宁化精确生产”奠定了基础,并对开发的原型系统进行验证。     

Assessment of manufacturing systems reconfiguration smoothness

The effect of the configuration selection on the smoothness and easiness of manufacturing systems reconfiguration process cannot be neglected, especially when dealing with reconfigurable manufacturing systems (RMS). The term “reconfiguration smoothness” is introduced in this paper to address this issue. In order to evaluate the level of reconfiguration smoothness (RS), a metric was developed to provide a relative measure of the expected cost, time, and effort required to convert from one configuration to another. This metric is composed of three components representing different levels of reconfiguration, namely; market-level reconfiguration smoothness (TRS), system-level reconfiguration smoothness (SRS), and machine-level reconfiguration smoothness (MRS). Rules are introduced to guide the development of execution plans for system-level reconfiguration, which we call “reconfiguration planning”. These plans help reduce the physical effort of reconfiguring the system. A case study is presented to demonstrate the use of the developed metric followed by sensitivity analysis to show the effect of changing different metric parameters. The results show how the developed metric provides a powerful relative assessment tool for the transitional smoothness between a current configuration and a number of candidate feasible configurations for the next period. This can affect the configuration selection decisions at the beginning of each configuration period.     

Agent-based middleware architecture for reconfigurable manufacturing systems

Modern manufacturing systems are expected to be flexible and efficient in order to cope with challenging market demands. Thus, they must be flexible enough as to meet changing requirements such as changes in production, energy efficiency, performance optimization, fault tolerance to process or controller faults, among others. Demanding requirements can be defined as a set of quality of service (QoS) requirements to be met. This paper proposes a generic and customizable multi-agent architecture that, making use of distributed agents, monitors QoS, triggering, if needed, a reconfiguration of the control system to recover QoS. As a proof of concept, the architecture has been implemented to provide availability of the control system understood as service continuity. The prototype has been tested in a case study consisting of an assembly cell where assessment of the approach has been conducted.     

Sandglass-type product specification management method for supporting modular design of semiconductor manufacturing equipment

The product life cycle for semiconductor manufacturing facilities has been significantly reduced as a result of the technological advancement of the semiconductor manufacturing process and the expansion of its demand. To ensure long-term market competitiveness under this environment, many companies attempt to convert their systems into mass customization production systems. In general, the specification management for semiconductor manufacturing equipment has adopted the method of making the bill of materials structure of the existing equipment into a new one based on the same physical structure and then customizing it according to a customer’s demands in the detail design phase. However, this method results in longer lead times and difficulties maintaining data consistency due to frequent design changes in connection with various derived products. We suggest a sandglass-type product specification management method to efficiently reflect varying and versatile requirements in product development and shorten the design lead time. In addition, we propose a method to support the modular design of semiconductor manufacturing equipment by classifying the standard specifications for a final product into product component and part component specifications. Finally, we develop a closed-loop product specification management system called NEXUS using our method, and apply this system to semiconductor manufacturing processes.

     

Production planning and performance optimization of reconfigurable manufacturing systems using genetic algorithm

To stay competitive in the new dynamic market having large fluctuations in product demand, manufacturing companies must use systems that not only produce their goods with high productivity but also allow for rapid response to market changes. Reconfigurable manufacturing system (RMS) is a new paradigm that enables manufacturing systems to respond quickly and cost effectively to market demand. In other words, RMS is a system designed from the outset, for rapid changes in both hardware and software components, in order to quickly adjust its production capacity to fluctuations in market demand and adapt its functionality to new products. The effectiveness of an RMS depends on implementing its key characteristics and capabilities in the design as well as utilization stage. This paper focuses on the utilization stage of an RMS and introduces a methodology to effectively adjust scalable production capacities and the system functionalities to market demands. It is supposed that arrival orders of product families follow the Poisson distribution. The orders are lost if they are not met immediately. Considering these assumptions, a mixed integer nonlinear programming model is developed to determine optimum sequence of production tasks, corresponding configurations, and batch sizes. A genetic algorithm-based procedure is used to solve the model. The model is also applied to make decision on how to improve the performance of an RMS. Since there is no practical RMS, a numerical example is used to validate the results of the proposed model and its solution procedure.     

基于二元增强学习架构的可重构制造系统调度

构建基于重构和调度二元增强学习架构的调度系统,借助重构增强学习系统的行为来实现资源配置、重构制造单元的功能,借助调度增强学习系统的行为来为各制造单元安排加工任务,实现优化各产品加工路径和加工顺序的功能.重构和调度增强学习系统通过状态转移、行为选择和报酬获取进行联系.提出结合函数泛化器的自适应步长增强学习算法的学习机制和学习步长调整机制,通过实验分析了函数泛化器的性能,验证了该算法解决一类重人型的可重构制造车间调度问题的有效性.     

Study on a process-centric modeling methodology for virtual manufacturing of ships and offshore structures in shipyards

The production processes in a shipyard are highly complex and take various forms owing to the project-like characteristics of the products. Thus, a shipyard’s competitiveness is determined by the level of production management capability that it possesses. Many shipyards have made great efforts to improve their productivity by introducing higher level planning systems and process management systems. More recently, they have extended these efforts through the introduction of virtual manufacturing. Virtual manufacturing makes it possible to realize an improved productivity through the use of modeling and simulation technology. As a result, it is possible to leave behind decision making based on mere intuition or past experience by establishing improved planning based on concrete quantitative data. This study newly defines a simulation modeling methodology that is suitable for the characteristics of shipbuilding. On the foundation of existing virtual manufacturing modeling methodologies, we apply the product, process, resource, and schedule (PPR-S) model, which is suitable for a shipyard production environment. A process-centric simulation modeling methodology is defined based on the process-centric nature of ship production, and a system for applying this methodology is designed. Since it is designed considering a variety of virtual manufacturing software, it has a high level of flexibility for application in the field of shipbuilding.     

Rapid one-of-a-kind product development

In today’s global market, more and more manufacturing companies have realised that the ability to quickly develop a customised product in an economic and efficient way is critical for them to survive in the keen competitive international market, particularly for one-of-a-kind production (OKP) companies. A new generation of OKP systems needs to be developed to maintain competitiveness in the global marketplace and to improve the ability to rapidly combine the strengths of manufacturing partners to meet market needs. In this paper, the main objectives of rapid OKP development in the global manufacturing environment are discussed. The background of recent approaches for rapid development of OKP products is reviewed. After systematically reviewing the existing OKP systems and recent developments of new technology and systems, the authors discuss current issues and requirements for developing a new generation of OKP systems for rapidly producing OKP products. At the end of this paper, a reference system structure is proposed for rapid development of OKP products in the global manufacturing environment .     

Part spectrum based methodology for cell sizing in flexible manufacturing systems

This paper describes a part spectrum based methodology which enables the determination of an optimum size for flexible manufacturing cells. The methodology incorporates a systems approach in that it enables the sizing of cells to achieve specified manufacturing objectives while maintaining a realistic level of flexibility and an acceptable level in terms of complexity of control.The proposed methodology for cell sizing is based on two component characteristics: processing time and number of operations. Furthermore, it is generalised in its implementation in that the effects of case specific factors such as processing sequence of components and location of machines in relation to each other are negated.The validation of the proposed methodology for cell sizing using data obtained from manufacturing companies implementing flexible manufacturing systems is also described.     

可重组制造系统

可重组制造系统是一种能够快速响应新的生产环境的新型制造系统，在快速响应市场变化和个性化生产方面具有重要的意义。阐述了可重组制造系统的发展历史、概念、分类、重组特性及其特点，评述了目前可重组制造系统的研究现状，讨论了可重组制造系统的关键技术，并提出了可重组制造系统应用研究的发展方向。     

Sustainable manufacturing: evaluation and modeling of environmental impacts in additive manufacturing

Cleaner production and sustainability are of crucial importance in the field of manufacturing processes where great amounts of energy and materials are being consumed. Nowadays, additive manufacturing technologies such as direct additive laser manufacturing allow us to manufacture functional products with high added value. Insofar as environmental considerations become an important issue in our society, as well as legislation regarding environment become prominent (Normalization ISO 14 044), the environmental impact of those processes have to be evaluated in order to make easier its acceptance in the industrial world. Some studies have been conducted on electric consumption of machine tools (standby consumption, in process consumption, etc.) but only a few studies take into account the whole existing environmental flows (material, fluids, electricity). This paper presents a new methodology where all flows consumed (material, fluids, electricity) are considered in the environmental impact assessment. This method coupled a global view required in a sustainable approach and an accurate evaluation of flow consumption in the machine. The methodology developed is based on a predictive model of flow consumption defined from the manufacturing path and CAD model of the part which will be produce. In order to get an accurate model of the process, each feature of the machine is modeled. The goal of this work is to integrate this model into the design loop for additive manufacturing parts.     

Flexible and reconfigurable manufacturing systems paradigms

Reconfigurable Manufacturing System (RMS) is a new manufacturing systems paradigm that aims at achieving cost-effective and rapid system changes, as needed and when needed, by incorporating principles of modularity, integrability, flexibility, scalability, convertibility, and diagnosability. RMS promises customized flexibility on demand in a short time, while Flexible Manufacturing Systems (FMSs) provides generalized flexibility designed for the anticipated variations and built-in a priori. The characteristics of the two paradigms are outlined and compared. The concept of manufacturing system life cycle is presented. The main types of flexibility in manufacturing systems are discussed and contrasted with the various reconfiguration aspects including hard (physical) and soft (logical) reconfiguration. The types of changeability and transformability of manufacturing systems, their components as well as factories, are presented along with their enablers and compared with flexibility and reconfigurability. The importance of having harmonized human-machine manufacturing systems is highlighted and the role of people in the various manufacturing paradigms and how this varies in pursuit of productivity are illustrated. Finally, the industrial and research challenges presented by these manufacturing paradigms are discussed.