Definition and Classification of Manufacturing Flexibility Types and Measures

Flexibility is one of the most sought-after properties in modern manufacturing systems. Despite this interest, flexibility remains poorly understood in theory and poorly utilized in practice. One reason for this is the lack of general agreement on how to define flexibility: over 70 terms (types and measures) can be found in the literature. This paper concerns developing a framework and classification scheme for use in defining and classifying the various terms regarding flexibility found in manufacturing. The framework consists of six attributes: level of manufacturing requirements specification, manufacturing system specification, manufacturing environment specification, flexibility dimension, flexibility measurement approach, and time frame. A six-field hybrid classification scheme is developed based on this framework. The framework serves as a guide for developing new flexibility terms, whereas the classification scheme provides a mechanism for summarizing the important aspects of and assumptions behind a given term. The approach is demonstrated by using the classification scheme to classify over 50 existing flexibility terms. The results indicate that the classification scheme is an effective tool to aid in understanding different flexibility terms and how they compare to one another. At the same time, the difficulty of the classification exercise indicates the need for a suitable framework when defining such terms.     

Logical Cell Formation in FMS, Using Flexibility-Based Criteria

Flexible manufacturing systems often are organized into a cellular architecture for ease of operation. The formation of these cells sometimes has been treated as an extension of the conventional cell-formation problem. This paper argues that, owing to the existence of flexible routing and transfer capabilities, the cell-formation problem in FMSs should be treated as quite distinct from that in conventional manufacturing systems and shows that a flexibility-based procedure is apt for overcoming the deficiencies of earlier forays into this area. Manufacturing cell flexibility is defined as a composite of three flexibility measures: producibility,processivity , and transferability. The problem of cell formation is modeled as flexibility maximization, and a procedure is developed for the simultaneous formation of machine cells and part families, while heuristically maximizing within-cell flexibility.     

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.     

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Internet的快速产品协同制造——DNPS网络及其实现技术

研究了企业如何利用 WEB/ INTERNET构造动态联盟以实现产品快速制造。探讨了利用 DNPS(分散网络化生产系统 )网络实现异地企业间制造资源与信息共享的框架和若干关键技术问题的实现方法。研究了在 DNPS网络环境下的虚拟企业结构模型和 DNPS的代理机制及其功能特点。探讨企业加入 DNPS及其DNPS代理的要求 ,并且提供了一种解决方案     

An Evaluative Study of Operation Grouping Policies in an FMS

The increased use of flexible manufacturing systems to provide customers with diversified products efficiently has created a significant set of operational challenges for managers. This technology poses a number of decision problems that need to be solved by researchers and practitioners. In the literature, there have been a number of attempts to solve design and operational problems. Special attention has been given to machine loading problems, which involve the assignment of job operations and allocation of tools and resources to optimize specific measures of productivity. Most existing studies focus on modeling the problem and developing heuristics in order to optimize certain performance metrics rather than on understanding the problem and the interaction between the different factors in the system. The objective of this paper is to study the machine loading problem. More specifically, we compare operation aggregation and disaggregation policies in a random flexible manufacturing system (FMS) and analyze its interaction with other factors such as routing flexibility, sequencing flexibility, machine load, buffer capacity, and alternative processing-time ratio. For this purpose, a simulation study is conducted and the results are analyzed by statistical methods. The analysis of results highlights the important factors and their levels that could yield near-optimal system performance.     

A methodology for investigating effects of cell size on operational flexibility in flexible manufacturing systems

There are two aspects to cell formation in flexible manufacturing systems, cell sizing or deciding on the optimum number of machines to be allocated to each cell, and then allocation of specific machines to each cell. Although the latter problem has been investigated extensively there is a paucity of published work on the former. This paper discusses the effects of cell sizing on operational flexibility.Operational flexibility is that aspect of flexibility that enables manufacturing systems to respond with speed and efficiency to changes in the manufacturing environment while maintaining an effective level of control.     

基于模块化的产业群集成制造研究

信息与网络技术的发展使产品制造呈模块化趋势,而模块化的企业以集群的方式形成了它特定的制造优势。本文运用模块化理论对产业群进行了模块化分析与评估,认为产业群是模块化与集成化的统一,是一种动态平衡;基于模块化的集成制造提高了产业群制造柔性及其企业的竞争力;实现产业群的集成制造就是在界面约束因子与柔性因子之间找到动态的平衡。     

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.     

Impact of operation flexibility and dispatching rules on the performance of a flexible manufacturing system

Operation flexibility is one of the eight common types of flexibility that exist in flexible manufacturing systems. Dispatching rules are commonly used in loading the machines. This paper studies the effects of different levels of operation flexibility and various dispatching rules on the performance of a flexible manufacturing system. The system performance considered is mean flow time. Simulation results indicate that the mean flow time cannot be always improved by increasing the level of operation flexibility. Altering the dispatching rules seems to have a more significant effect on the mean flow time performance than changing the level of operation flexibility.     

Impact of reliability on warranty: A study of application in a large size company of electronics industry

This paper presents product reliability on component basis and investigates the possible effects on warranty which constitutes a non-technical issue. Product reliability is a key factor, which is used in considering the warranty period. It plays a significant role that a mistake in warranty forecasting could cost a lot for companies. The objective is to empirically examine the nature of general reliability of manufactured goods and conduct a case study in an electronics company. In this regard, reliability will be stated from the actual manufacturing point of view. A case study was applied in manufacturing industry. LCD TVs were undertaken to follow. To test reliability, a parametric Weibull model was used and hazard rates of products were estimated with linear regression method. For this research work, the lifetime data obtained by service departments, censored both left and right. Data were used in MINITAB14 to produce the reliability results of the LCDs to reveal the relationship between product reliability and product warranty in the consumer electronics industry. In this manner, this paper would help the company to decide whether it is favorable to extend the warranty period based on the failure findings.     

Green supply chain management in local and multinational high-tech companies located in Brazil

The objective of this article is to analyse how green supply chain management (GSCM) practices are being adopted by some high-tech companies located in Brazil. The research was conducted using the case study approach, focusing on eight companies that are representative of this sector. The main results are: (a) the most adopted GSCM practices in the studied high-tech companies located in Brazil are internal environmental management, investment recovery and reverse logistics and (b) Brazilian environmental legislation and international policies are very important in driving the adoption of GSCM practices. The internationalisation of companies was also found to be a variable that interferes with the adoption of GSCM practices. This is one of the first studies that examine the relationship between GSCM and the internationalisation of companies located in Brazil.     

Advanced manufacturing techniques and information technology adoption in India: A current perspective and some comparisons

This paper explores the issues of measurement and comparison of the current state of advanced manufacturing technology (AMT) adoption in India, including important information technology (IT) factors, and, surprisingly, this appears to be the first such attempt. For a worldwide perspective, comparison is made between Indian firms, firms in a developed country (Canada), and in a developing country (China). Contrary to expectation, the average score of AMT adoption degree of Indian companies in our survey is higher than that of all Canadian companies (when unadjusted for size) and of Chinese companies in one of the highly industrialized regions of China as measured in other surveys. While this suggests considerable strength of the Indian manufacturing sector, there should be further evaluation by other studies in this area to refine and develop these results. This study finds the top six AMTs currently adopted in India are plant certification, computer aided design, local area network, quality circle, MRP/ERP, and wide area network. Clearly four of these top six are directly in the IT area (CAD, LAN, WAN) or directly dependent on it (MRP/ERP systems), indicating a strong IT adoption rate as well as its underlying supportive role in the overall AMT adoption in India. The comparison between Indian firms and Canadian firms indicates that Indian firms adopted computer networks less and MRP/ERP and rapid prototyping systems more. Tests in our survey also reinforce the hypothesis that larger companies are more likely to adopt AMT than the smaller ones.     

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.     

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.     

储气库大功率往复压缩机组成撬API 618优化设计

API 618第五版标准详细规定了往复压缩机组在成撬设计中的气流脉动和机械振动分析要求(相当于第四版的M2-M7分析),但对管道柔性分析部分(相当于第四版的M11分析)则描述不多,仅在方法二中以注释形式简单提及。从机组实际使用情况来看,往复压缩机组特别是大功率储气库机组在成撬设计过程中,仅仅满足振动控制要求是不够的,还需同时满足管道柔性要求。以某储气库大功率往复压缩机组三级进气缓冲罐设计优化为例,说明如何在大功率往复压缩机组成撬设计过程中既考虑满足振动控制要求、又考虑满足管道柔性要求的优化设计方法,为提高储气库大功率往复压缩机组运行安全性提供技术参考。     

基于仿真的单元化制造系统柔性布局研究

针对单元化制造系统存在的柔性问题,进行设备布局的仿真实验研究;提出了基于车间布局的制造系统柔性评价指标;分析了改善单元化制造系统柔性的几种布局方式。用改变设备布置为手段,通过仿真实验,总结出改善单元化制造系统柔性的有敦方法。     

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。     

供应链性能评价指标体系的研究

对供应链的性能评价方法进行了系统研究，分析了选择性能指标的基本要求，提出了一种新的基于性能指标分析的供应链作业性能评价方法，并从供应链的输入、输出、资源及柔性四方面建立了全面的供应链性能评价指标体系，定义了销售柔性、付货柔性、生产柔性和设计柔性及其计算公式，提出了改进供应链性能的一些基本措施。