Influencing factors of synchronization in manufacturing systems

Manufacturing systems exhibit two types of synchronisation phenomena: logistics and physics. Previous research has established synchronisation measures for both types and has shown that they are related to the due date performance. However, there is a lack of knowledge about the factors triggering synchronisation emergence as well as a holistic understanding of synchronisation effects on logistics performance. Thus, this research aims to further explore the relation between synchronisation, its influencing factors and its effect on logistics performance. Based on a profound literature review, we derive first hypotheses on the cause-and-effect-relationships between structural and dynamic properties of a manufacturing system and the emergence of logistics and physics synchronisation as well as logistics performance. By conducting a discrete-event simulation study on diverse manufacturing system types (line, flow shop and job shop production), we are able to test these hypotheses. We conclude that manufacturing network architecture as a structural property as well as processing time variability and system workload as dynamic properties may be exploited for an advanced and synchronisation-oriented manufacturing system design.     

Performance analysis for serial production lines with Bernoulli Machines and Real-time WIP-based Machine switch-on/off control

In recent years, achieving high energy efficiency has become one of the primary goals in manufacturing, along with maintaining high productivity and quality. In many manufacturing systems, it is sometimes possible to temporarily switch off a machine to reserve energy, and switch it back on when a certain condition is met. Indeed, production control-based shop floor continuous improvement is recognised as one of the most cost-effective ways to achieve energy-efficient production. In this paper, we study serial production lines with Bernoulli machines and finite capacity buffers and assume that some of the machines in the line can be switched on and off during the production process according to a state-based feedback control policy. Mathematical models for the system under consideration are derived and analytical methods are developed for calculating the system performance measures during transients. Specifically, exact Markovian analysis is used for two- and three-machine lines in which the switch-on/off operations of only one machine is considered. For longer lines, the switch-on/off operations of multiple machines are considered and an aggregation-based approximation approach is applied to evaluate the system performance measures. Numerical experiments show that the method developed can be used to efficiently calculate the system’s performance with high accuracy.     

From production systems to health care delivery systems: a retrospective look on similarities,difficulties and opportunities

Manufacturing systems have attracted substantial research attentions during the last 50 years. In recent years, there has been growing interest in health care systems research to improve efficiency, safety and care quality. The similarities identified between manufacturing systems and health care delivery systems heighten the importance of transferring the experience and knowledge in manufacturing to health care. In this paper, based on the lessons we learned and the experience we obtained during our journey from production systems research to health care delivery systems study, we discuss the similarities between production systems and health care delivery systems in system modelling, design, performance evaluation and continuous improvements and investigate the differences and difficulties that stem from variability, constraints, dynamics and human behaviour. Building upon these, the opportunities encompassing care operations, planning and scheduling, patient transitions, and safety and teamwork in health care delivery systems are discussed. Finally, the challenges and future directions are proposed. We expect this work to serve as a catalyst to stimulate more in-depth and comprehensive studies.     

RFID-based multi-attribute logistics information processing and anomaly mining in production logistics

Timely collecting logistics information and finding anomalies of material supply plays a critical role in modern manufacturing systems. The problem is how to obtain multi-attribute logistics information of production logistics and build an effective approach for mining anomalies from the huge number of RFID data. The multi-attribute, randomness and various measure units of logistics states further aggravate the problem. In this paper, a novel RFID-based logistics information processing approach is proposed. Firstly, the state features of production logistics is discussed from multi-attribute perspectives including time, location, quantities, sequence and path, and a set of calculating models is set up to process RFID data for getting multi-attribute state data. Furthermore, in case of the randomness and various measure units of state data, a similarity model is presented to unify measure units of state data, and a clustering approach is proposed to divide the huge number of RFID data into different clusters with high close degree for finding out anomalies. Lastly, the experimental results show that the proposed approach can efficiently find out more than 90% of anomalies among production logistics.     

Analytical models to predict the performance of a single-machine system under periodic and event-driven rescheduling strategies

This article presents initial results in the search for analytical models that can predict the performance of one-machine systems under periodic and event-driven rescheduling strategies in an environment where different job types arrive dynamically for processing and set-up must incur when production changes from one product type to another. The scheduling algorithm considered uses a first-in firstout dispatching rule to sequence jobs and it also groups jobs with similar types to save set-up time. The analytical models can estimate important performance measures like average flow time and machine utilization, which can then be used to determine optimal rescheduling parameters. Simulation experiments are used to show that the analytical models accurately predict the performance of the single machine under the scheduling algorithm proposed.     

浅谈MES系统在莱钢宽厚板的应用

宽厚板生产管理是一项庞大而又复杂的系统工程,它具有严格按合同组织生产、多规格、小批量、物流交叉等特点,为强化生产管理,实现物流和信息流的同步,实现经营管理与制造管理有机结合,实现信息的无缝链接与共享,建立现代化的生产制造执行系统（MES）成为必然选择。     

Effectiveness of planning and control systems: An empirical study of US and Japanese firms

Both researchers and practitioners have investigated the effectiveness of manufacturing planning and control systems (MPCS) in an attempt to justify the investment in MPCS. This study uses the Wight's (1981) detailed questionnaire to measure the degree of planning and control implementation in a manufacturing system, which is referred to as MPCS rating. The MPCS rating is then used to study the relationship between the self-assessed manufacturing competitiveness (cost, quality, delivery and flexibility) and the objective performance measures of manufacturing performance such as production cost, productivity change, customer reject percent, manufacturing lead time, etc. The results show that there is a strong relationship between MPCS ratings and objective performance measures as well as self-assessed competitiveness in both Japanese and US firms. The results are important since they indicate that fundamental manufacturing planning and control procedures improve a firm's performance on both its internal operations as well as external competitiveness goals.     

Integrated analysis of quality and production logistics performance in manufacturing lines

This paper presents an analytical method for evaluating the performance of production systems, jointly considering in a unique framework quality and production logistics performance measures. In the literature, quality and production logistics have traditionally been investigated using independent approaches. Thus far, only a few recent contributions have focused on their mutual inter-relation, showing that benefits can be achieved from an integrated analysis. This paper contributes to this growing research by considering, for the first time, production systems in which the behaviour of the machines is monitored by statistical control charts. The control action performed by the quality control system on the machines is directly modeled. Moreover, the impact of the quality control action on the logistic flow of parts in the system is taken into account. In order to estimate the performance of such systems, an approximate analytical method based on the system decomposition technique is developed. The accuracy of the method is assessed by comparing the results with those obtained by simulation. Analysis of the results provides new insights into the relations among the quality and production logistics performance measures and paves the way to the development of integrated design techniques for improved configurations of the system as a whole.     

Guidelines for implementing robust supervisors in flexible manufacturing systems

Over the past several years, researchers have developed numerous control policies that assure deadlock-free operation for flexible manufacturing systems. Using this research base as a foundation, we have developed several supervisory policies that assure robust operation in the face of resource failure. Along with deadlock-free operation, these policies guarantee that failure of unreliable resources does not block production of part types not requiring failed resources. In our previous work, we developed two types of robust policies, those that ‘absorb’ all parts requiring failed resources into the buffer space of failure-dependent resources (resources that support only parts requiring failed resources), and those that ‘distribute’ parts requiring failed resources among the buffer space of shared resources (resources shared by parts requiring and parts not requiring failed resources). These two types of robust controllers assure different levels of robust system operation and impose very different operating dynamics on the system, thus affecting system performance in different ways. In this research, we use extensive simulation and experimentation on a highly complex and configurable system to develop guidelines for choosing the best robust supervisor based on manufacturing system characteristics and performance objectives. We validate these guidelines using seven randomly generated complex systems and find a better than 88% agreement.     

Throughput analysis of production systems: recent advances and future topics

Throughput analysis is important for the design, operation and management of production systems. A substantial amount of research has been devoted to developing analytical methods to estimate the throughput of production systems with unreliable machines and finite buffers. In this paper we summarise the recent studies in this area. In addition to the performance evaluation of serial lines, approximation methods for more complex systems, such as assembly/disassembly systems, parallel lines, split and merge, closed-loop systems, etc., are discussed. Moreover, we propose future research topics from the automotive manufacturing systems perspective.     

Aggregate production process design in global manufacturing using a real options approach

A main source of competitive advantage is derived from the cost efficiency offered by firms’ manufacturing and logistics operations. Consequently, firms typically globalise their operations whereby they may exploit the comparative advantages—defined as production functions—of the nations in which they are present. Production process design thus arises as a significant issue. The research presented in this paper targets two fundamental questions attached to production process design that multinational companies face, namely: (i) should plants that are located in different countries but producing similar products use similar production processes?; and (ii) given that the firm's policy is to use similar production processes, how should the production processes be designed? Among others, the paper shows, by way of a numerical illustration of a binational manufacturing network, that the option of choosing freely upon production process design for the respective facilities in certain cases adds little to firm value. In fact, the value of this option tends to zero as the volatility rate increases when the exchange rate is modelled as a geometric Brownian motion without drift rate, implying that firms should employ similar production processes throughout their manufacturing networks. That is, a market value approach stands up for the so-called copy-exactly approach to production process design in these settings. We furthermore show the effects of economies of scale on the optimal production process design.     

Performance evaluation of two-stage multi-product kanban systems

We propose an approximate evaluation procedure for a kanban-controlled production system with two stages and multiple products. In the first stage, single-product manufacturing facilities produce items that are the input material for a single multi-product manufacturing facility in the second stage. Each manufacturing facility is controlled by a distinct kanban loop with a fixed number of kanbans. Processing and setup times are exponentially distributed, demand arrivals at the output store of the second stage are Poisson and independent for each product. If a customer's demand cannot be met from stock, the customer either waits or leaves the system, depending on the admissible number of backorders and the current number of waiting customers (partial backordering). We describe a new decomposition-based approximation method for the evaluation of such systems in steady state. We focus on the performance measures average fill rate, average fraction of served demand, and average inventory level. We report the results of several numerical tests. The results indicate that the approximation is sufficiently accurate for a large variety of systems. We also illustrate the effects of increasing the maximum number of backorders on the performance of the system.     

Classification of queueing models for a workstation with interruptions: a review

Queueing theory is commonly used to evaluate the performance of production systems. Due to the complexity of practical production lines, choosing correct queueing models under the existence of interruptions can be intricate, but is critical to the evaluation of system performance. This paper gives a review of research in this area, proposes a systematic way to classify different types of interruptions in manufacturing systems and suggests proper queueing models for each category. The operational definition of service time is given and the decomposition properties for the run-based state-induced and time-based preemptive events are explained. The corresponding G/G/1 approximate models are proposed.     

基于蚁群算法的中小手工制造企业人员调度

根据多品种、变批量的插单式生产的复杂特性,利用集群智能这种复杂系统建模手段研究中小企业生产线组建和人力资源调度过程。在将离散的生产单元运行特点与蚁群劳动分工模型进行对比分析的基础上,根据生产任务的要求和各个生产单元的负载不同重新设计工人的属性特征和员工间调配方案,实现了由计算机自动控制的自适应劳动分工模型。实验表明数字仿真结果大致与实际情况吻合。运行结果体现了非流水线手工作业生产中的劳动力分配的自组织自适应特征。     

Supply-chain performance-measurement system management using neighbourhood rough sets

Performance measurements are central to improving organisational competitiveness. Organisations and researchers have developed and investigated various performance-measurement systems to manage and improve internal and external operations for logistics and supply chains. Yet, formal modelling tools and approaches for organisations to help evaluate the relationships between the performance measures and the desired competitive outcomes are limited, especially in logistics and supply-chain management functions. To help address this gap, we introduce a novel application of neighbourhood rough-set theory for the identification and selection of performance measures related to externally derived desired outcomes on the sourcing function. Our contribution includes introducing an innovative neighbourhood rough-set approach using elements of the Supply-Chain Operations Reference model. The model may aid in determining a core set of external logistics and supply-chain performance measures to internal performance expectations and outcomes. Implications and results interpretation of the methodology, sensitivity analysis, limitations, and future research directions conclude the paper.     

基于柔性生产的生产物流平衡策略研究

柔性生产的有效开展需要保持生产物流始终处于平衡状态。研究了柔性生产下如何保持生产物流平衡的策略问题。首先分析了柔性生产下生产物流平衡的内容,然后就如何平衡生产物流进行了深入探讨。研究结果表明,提高生产的负荷率、均衡率和合同的完成率,这是柔性生产下平衡物流的目的,也是物流平衡的主要内容;而保持生产线平衡、识别瓶颈资源、编制好生产作业计划、设置缓冲环节则是平衡生产物流行之有效的关键手段和策略。     

Implementation of service systems on the shop-floor level in financial service companies. Empirical evidence from Australia and Germany

This article presents the practices of Australian and German financial service providers regarding the implementation of shop-floor control within different types of service systems. The results delivered in this article should serve as a guideline for future research to develop and adapt methods for shop-floor control in financial service systems. Interviews with 25 experts from the Australian and German financial services industry reveal novel insights into the practice of shop-floor control, suggesting that methods and concepts from manufacturing are only used to a limited extent for shop-floor control. Shop-floor control is mostly used to react quickly to unexpected deviations due to a low usage of forecasts and information systems. Thus, there seems to be improvement potential in the financial services industry in comparison with in the manufacturing industry in terms of shop-floor control. Further research within the production research area should use the empirical insights to test and adapt existing methods and to develop new ones, taking cultural differences into account.     

Performance comparison of multiple product kanban control systems

Kanban control systems have been around for decades and have been used to control work-in-process of manufacturing systems. Lately many variations of the basic control system have been developed; however, much of the work in the development and comparison of control systems has focused on a single-stage manufacturing system producing a single product type. In this research, we present procedures for optimising multiple product kanban control systems, namely Base Stock, Traditional Kanban Control System and Extended Kanban Control System (both dedicated and shared type). We then conduct a detailed simulation study to compare the performance of the systems using a common total cost measure. Numerical results show that the dedicated and shared-extended kanban control systems outperform the other two systems. The study also shows that in spite of their different schematics and contrary to conventional wisdom, the performance of dedicated and shared-extended kanban control systems doesn’t differ much.     

Applicability of lean production with VSM to the Rioja wine sector

Lean production arose as a step towards a new era in production systems. It is a working philosophy designed to produce better products using fewer resources to obtain greater benefits. It has been applied to a wide variety of sectors different from the original automotive industry, in which it was developed. However, its application to continuous manufacturing processes of continuous products has been less, especially to the wine-production sector. The wine sector differs greatly from the automobile sector in various fundamental aspects, but it also has common fundamental aspects in its production and logistics systems. An important part of this work has consisted in studying the wineries of the Rioja region. This article analyses the applicability of lean production in the La Rioja wine sector and the results that may be obtained from its application, using value stream mapping as the main tool to identify opportunities for improvement. This piece of research shows that most of the production problems in the wine sector can be tackled using a lean production system, making certain adjustments according to the type of production. It shows the main properties of wine production from the lean viewpoint, and it improves the production and logistics systems.     

Perceived production complexity – understanding more than parts of a system

To successfully manage today’s complex production systems it is essential to study operators’ perception of the system. The paper presents perceived production complexity assessed at seven manufacturing companies with the CompleXity Index (CXI) method. While other methods have measured product variants, layout, work content, tools and information items, CXI combines them into three areas. These three complexity areas (Station design, Work variance and Disturbance handling) help to create an understanding of the complex system by visualising how they contribute to complexity, and show the need to support the operators’ ability to handle the varying work.