Manufacturing Flexibility: Assessing Managerial Perception and Utilization

This paper presents an empirical study of how consumer electronics companies in Brazil deal with the issue of manufacturing flexibility. The main purpose is to provide an understanding into how flexibility is being perceived and utilized in a newly industrialized country. It begins by explaining the relevance of this study. The participation of Brazil in the world economy is important. Here, companies can be very flexible, based on low cost and an abundant skilled work force, yet flexibility has not been addressed. The paper explains how indicators were established to obtain an analytical structure with which to assess the managerial perception and the actual industrial use of flexibility. Finally, we show the most relevant results of our investigation of 16 leading firms in Brazil, including multinational ones. The findings are divided according to managerial perception of flexibility and effective utilization of flexibility in the organization. The paper concludes that firms in the consumer electronics industry in Brazil do not use flexibility practices in the same proportion that they perceive its importance.     

Machine Sharing in Manufacturing Systems: Total Flexibility versus Chaining

In this paper, we compare the operational performance of two machine-sharing configurations: total flexibility and chaining. We show that chaining captures most of the benefits of total flexibility while limiting the number of part types processed on any individual machine to only two. We examine the relative desirability of the two configurations under varying buffer sizes, loading conditions, number of machines, and setup times, as well as for different control policies. For nonzero setups times, we show that chained configurations can outperform fully flexible ones. This particularly is the case when either the number of machines or length of setup times is high. We also find that the effect of the system size on performance diminishes with the number of machines. This means that multiple smaller chains can perform almost as well as a single long one. Our results are consistent with the recent findings of Jordan and Graves (1995), who examined the economic benefits of chaining relative to full flexibility.     

基于节拍平衡的高柔性数控单元调度研究

为提高柔性数控单元生产效率,提出一种基于工序平衡的高柔性数控单元调度方法。第一阶段,根据产品生产工艺和设备生产能力进行工艺路线规划,在考虑生产约束、生产准备时间、工艺柔性和设备产能的基础上,构建产品节拍平衡优化目标,获得其最优加工视图组合;第二阶段,基于工序平衡的结果,在考虑产品换线时间的基础上构建整单调度模型,并采用遗产算法求解。最后,将所提调度方法在某壳体产品高柔性数控生产单元进行应用研究,并与分批量调度模型进行了比较分析。研究表明,所提出的工序平衡的柔性数控单元整批量调度方法可以有效缩短单元的制造周期,提高单元控设备利用率。     

Flexibility in manufacturing: A survey

This article is an attempt to survey the vast literature on flexibility in manufacturing that has accumulated over the last 10 to 20 years. The survey begins with a brief review of the classical literature on flexibility in economics and organization theory, which provides a background for manufacturing flexibility. Several kinds of flexibilities in manufacturing are then defined carefully along with their purposes, the means to obtain them, and some suggested measurements and valuations. Then we examine the interrelationships among the several flexibilities. Various empirical studies and analytical/optimization models dealing with these flexibilities are reported and discussed. The article concludes with suggestions for some possible future research directions.     

Evaluating the design of flexible manufacturing systems

Evaluating the design of flexible manufacturing systems is complex. Developing a measure of performance useful for evaluating alternate designs continues to be interesting. Here, total productivity of the system is proposed as an appropriate measure. Specification of parameters based upon strategic considerations for this measure are discussed. Finally, the usefulness of the measure is demonstrated through an example.     

The Effects of Scheduling Rules and Routing Flexibility on the Performance of a Random Flexible Manufacturing System

The increased use of flexible manufacturing systems to efficiently provide customers with diversified products has created a significant set of operational challenges for managers. Many issues concerning procedures and policies for the day-to-day operation of these systems still are unresolved. Previous studies in this area have concentrated on various problems by isolating or simplifying the systems under study. The primary objective of this study is to extend previous research by examining the effects of scheduling rules and routing flexibility on the performance of a constrained, random flexible manufacturing system (FMS). Other experimental factors considered are shop load, shop configuration, and system breakdowns. Within the bounds of this experiment, the results indicate that, in the presence of total routing flexibility, the effects of shop load, system breakdowns, and scheduling rules are significantly dampened. In particular, when total routing flexibility exists, the choice of scheduling rules is not critical. We also show that the behavior of scheduling rules in a more constrained FMS environment (i.e., where system breakdowns occur and material handling capability is limited) is consistent with the findings of previous research conducted under less constrained environments. Finally, results indicate that the shop configuration factor has little or no impact on a system's flow-time performance.     

实现大规模定制的柔性分析

为满足客户化和全球竞争的需求，企业需要实现大规模定制。然而，大规模定制的实现需要进行制造过程重组——一项有风险的任务。柔性是先进制造系统的重要特征，对于大规模定制来说尤其如此。基于系统的柔性分析，提出了一种为实现大规模定制的制造过程重组的方法，并通过一个简单的案例来说明方法的应用。     

Dissimilarity Maximization Method for Real-time Routing of Parts in Random Flexible Manufacturing Systems

This paper presents a dissimilarity maximization method (DMM) for real-time routing selection and compares it via simulation with typical priority rules commonly used in scheduling and control of flexible manufacturing systems (FMSs). DMM aims to reduce the congestion in the system by selecting a routing for each part among its alternative routings such that the overall dissimilarity among the selected routings is maximized. In order to evaluate the performance of DMM, a random FMS, where the product mix is not known prior to production and off-line scheduling is not possible, is selected for the simulation study. A software environment that consists of a computer simulation model, which mimics a physical system, a C++ module, and a linear program solver is used to implement the DMM concept. In addition to DMM, the simulation study uses two priority rules for routing (i.e., machine) selection and seven priority rules for selecting parts awaiting service at machine buffers. The results show (1) DMM outperforms the other two routing selection rules on production rate regardless of the part selection rule used, and (2) its performance is highly dependent on the part selection rules it is combined with.     

知识化制造系统——新一代先进制造系统

首先讨论了将先进制造模式转化为先进制造知识的必要性和可行性,以及现有商品化软件的缺陷;然后提出一一种知识制造系统新理念。这是一种高智能生物化制造系统,并讨论了其体系结构、功能结构、逻辑层次、关键技术和已有的研究基础。     

A Comparison Between Machine Flexibility and Routing Flexibility

In this paper, we evaluate two types of flexibility, machine flexibility and routing flexibility, in terms of manufacturing performance in various shop environments. A simulation-based investigation was conducted to analyze the impact of these types of flexibility on the average flow time of parts under various job flow pattern conditions, which characterize the shop nature from a random job shop to a flow shop, operation time variance, setup time, and shop load. The experimental results show how these types of flexibility affect the average flow time of parts and which type is superior under what conditions. Management can obtain better insight and guidelines for determining priorities or the scale, or scope, of various decision items relating to design standardization, process and operations improvement, investment in new equipment and tools, and the like.     

现代制造产业的信息化趋势及其影响

物质、能量和信息是构成制造系统的三大要素，其中物质和能量在历史上曾经占据主导地位，在制造产业中受到重视、研究、开发和应用。可是，随着信息时代的到来，信息这一要素正在地上升为制约系统的主导因素，并对制造产业实质性的影响。人们需要更新思想观念，以适应和促进这一趋势。本文分析这一发展及其影响。     

敏捷制造单元控制系统的参考模型

在分析了对单元控制器的要求的基础上,提出一个模块化的基于消息传递的通用参考模型,并对参考模型进行结构描述,功能描述、性能描述和信息描述。参考模型的提出为敏捷制造模式下的单元控制系统的设计提供了有力的支撑。     

先进制造模式的分类研究

综述了近年来国内外出现的各种先进制造模式，以及关于制造模式的分类方法，针对模式特征从制造哲理、制造的系统方法和具体的技术和方法3个方面，分3层将各种制造模式归类。最后，从制造哲理的角度讨论了各种制造模式的关系，并且指出先进制造模式的共同特征。     

The measurement of flexibility in manufacturing systems

This article provides a theoretical basis for measuring the flexibility of manufacturing systems. The concept of multiple levels of measures (necessary, capability, actual, inflexibility, and optimality) for each flexibility type is introduced. Capability and actual measures are then developed for machine, routing, process, product, and volume flexibilities. For each of these flexibility types, a state defining variable is identified. A measure of flexibility is then derived by computing either, (i) the change effort expended in moving between states, (ii) the drop in system performance in moving between states, (iii) a general or physical scale of difference between two successive states, or (iv) a measure combining all three. The use of the developed measures is illustrated via a two-facility example.     

基于试制白车身生产线柔性能力改造研究

为解决试制白车身生产线实现两种车型白车身的共线生产问题,展开对该生产线柔性能力的分析研究,通过改造优化白车身BOP制造工艺,调整各焊合零件的工艺流向,调整焊接设备和拼装夹具的布置,提高焊钳的通用性,提高夹具平台柔性化,实现生产场地利用率最大化,生产设备利用率最大化,最大限度发挥白车身生产线的柔性生产能力,实现最大化的低成本样车制造工作。     

新型制造企业轮图及其功能研究

介绍新型制造企业轮图的内容与特点，根据机械制造的现状与发展，对顾客中心作用、技能信息化和极端工艺技术等问题进行了研究。     

弹簧挠性设计和装配

以模具中卸料机构弹簧的设计与组装为例,介绍了弹簧的挠性设计与装配的步骤。     

制造系统的可重构性

可重构制造模式是一种指导管理和控制制造系统重构过程的制造哲理,它使制造系统有效地响应不断变化的环境,制造系统具有可重构能力是其生存和发 基本手段,具有较高可重构笥的公司在风云突变的环境中将远远超过其竞争对手。本文探讨了可重构造模式的基本定义和内涵,并从组织、过程、产品加工系统和信息平台等五个方面研究了制造系统的可重构性。     

规则引擎技术在制造执行系统中的应用研究

对制造执行系统和规则引擎特点进行分析后,针对传统制造执行系统的不足,设计实现了一个基于规则引擎的制造执行系统,以增强系统的柔性和实用性.最后,详细阐述了在该系统中执行一条用户定制规则的内部实现机制.     

柔性(Flexibility)的概念及其控制模型

对柔性的定义及其含义进行了全面的剖析，测重从柔性的能力构成分析了缓冲能力，适应能力，创新能力，从柔性的潜在性和表现性分析了现实柔性，可实现柔性和潜在柔性。在柔性控制中讨论了柔性的能力构成与柔性的表现形态的关系。