A comparative study of FMS tool allocation and part type selection approaches for a varying part type mix

Hankins and Rovito (1984) examined the impact of different tool policies on cutting tool inventory levels and spindle utilization for a flexible manufacturing system (FMS). This study provides a broader perspective of the impact of tool allocation approaches on flow times, tardiness, percent of orders tardy, machine utilization, and robot utilization. Part type selection procedures have been suggested for the FMS prerelease planning problem. However, very little research has specifically evaluated the part type selection procedures across different tool allocation approaches. Also, with the exception of Stecke and Kim (1988, 1991) no other known study has provided any insights on what tool allocation approaches are appropriate when processing different mixes of part types. This research is devoted to addressing those issues.Three tool allocation approaches, three production scheduling rules, and three levels of part mix are evaluated in this study through a similation model of a flexible manufacturing system. The specific impacts of the tool approaches, their interaction effects with the part type selection rules, and their effectiveness at different part type mix levels are provided through the use of a regression metamodel.     

A case study in FMS production planning and dispatching

The speedy development and extensive application of computers have helped play a significant role in a new technological revolution. The importance of FMS flexibility in producing a variety of products and adapting rapidly to customer requirements makes FMSs attractive. Further, FMSs are most appropriate for largevariety and medium- to high-volume production environments. However, the module of the FMS production planning system is not perfect. This paper focuses on a new scheme for FMS production planning and dispatching under the realistic assumptions promoted by a particular flexible manufacturing factory. Some practical constraints such as fixture uniqueness, limited tool magazine capacity, and a given number of pallets are considered. The simulation results indicate that the scheme provides a good production plan, according to the short-term plans from the MIS Department. Some conclusions are drawn and a discussion is presented.     

An integrated decision support system for FMS production planning and scheduling problems

This paper discusses planning and scheduling problems for efficient use of an FMS and presents an integrated decision support system for dealing with these problems.The decision support system, FMSDS (Flexible Manufacturing Systems Decision Support System), includes several modules: data handling module, part selection module, loading module, load adjusting module, scheduling module and simulation module.This paper suggests the solution methodology of each subproblem. Also, an integrated interface scheme between the subproblems is presented. The interface scheme considers the relationships between the subproblems and generates solutions using hierarchical and looping approaches.FMSDS is made up of six alternative models considering three loading objectives and two production order processing strategies. Performance comparison among the six alternatives is shown using the non-terminating simulation techniques.     

Algorithms for efficient planning and operation of a particular FMS

This article is a detailed case study of a particular FMS that will be operational in 1989. It describes the daily planning and operating problems that will need to be addressed. The algorithms that will operate this system are presented. Given the daily changing production requirements, the algorithms begin with an aggregate planning feasibility check. Then planning, scheduling, inventory management, and breakdowns are addressed.The key problems in operating this system are tool management problems. Detailed tooling data and their analysis are presented in an appendix to address these problems.     

An integrated scheme for process planning and scheduling in FMS

Process planning and scheduling are the two important manufacturing functions involved in any shop floor activities. As functional integration is essential to realize the benefits of computer integrated manufacturing, a scheme for integration of process planning and scheduling has been introduced in this paper. The proposed scheme can be implemented in a company with existing process planning and scheduling departments when multiple process plans remain available on the shop floor. It consists of two main modules, introduced in detail in this paper. They are process plan selection module and scheduling module.     

面向大规模定制的生产计划编制方法

在分析大规模定制的基本思想、生产特点及产品结构特点的基础上,讨论了在大规模定制下传统MRPII系统在产品项目编码、产品结构定义、生产计划编制等方面所遇到的问题,提出了用"产品族码"和客户订单号来唯一标识定制产品代码,并利用专家系统技术,通过产品族结构和产品配置知识库的建立,产生动态的"定制BOM";同时,本文提出了面向大规模定制的生产计划编制方法:对标准型产品及其通用模块采用标准MRPII模式组织生产,而对定制产品在已有标准型产品、通用模块的基础上进行生产和装配计划,最终向客户提供个性化的定制产品,实现了与标准:MRPII系统的集成.     

柔性制造系统中生产调度问题求解的一种符号算法

讨论了基于有序二叉决策图的有界Petri网符号分析,给出了其中镜像计算的一种新算法,进而建立了柔性制造系统生产调度问题的符号有序二叉决策图求解算法.该算法在求解过程中通过对状态空间及其搜索过程中相关数据的有序二叉决策图表示,避免了状态和搜索的显示枚举,实现了隐式高效操作,进而改善了算法的计算性能.仿真实验表明了算法的有效性.     

基于模块化的生产线规划研究

利用模块化设计思想,提出一种基于模块化的生产线规划方法。利用遗传算法对模块进行构建或重构。该方法将可重构单元作为生产线的基础模块,通过对基础模块的增删或调整,达到了改变单元和生产线的加工能力的目的。     

Production planning of FMS under tool magazine constraints: A dynamic programming approach

Production planning is one of the most important activities for efficient operation of a flexible manufacturing system. This complex acivity is concerned with the decisions related to system set-up, involving solving the problems of selection of a set of part types for simultaneous processing, determining the production ratios, assigning the pallets and fixtures, and assigning operations and tools to machines. In this paper, a dynamic programming algorithm is developed to solve the above problems simultaneously by considering the flexibilities and constraints of the system in order to minimise the unbalanced workload of machines. In this context, various factors such as the tools required for operations, alternative routes available for operations, tool magazine capacity and the limited number of pallets and fixtures are considered. The method is validated with a case study.Notation B a large number - i part type,i=1,...,N - o operation,o=1,...,O _i - k machine,k=1,...,K - j stage,j=1,...,N (N is maximum number of stages required, i.e. equal to the number of part types) - n indicates the number of parts to be introduced into the system (represents the state in DP),n=j,...,nmax. In stagej at least one number of each part type should be introduced into the system. The maximum number of parts can be a user defined maximum,nmax. - P _iok processing time of part typei, operationo on machinek - OA _io set of operation alternatives available for part typei, operation - o an alternative consists of machine number, tool number along with its processing time - pw _ik average workload required by a part typei on machinek - a _i number of parts (ratio) of typei - f _i number of fixtures available to part typei - S(j) {S ₁(j),S ₂(j),...,S _p (j),...}, whereS _p (j) ispth set of selected part types with cardinalityj - |S(j)| ^N C _j - W _k a constant, indicating the average unbalanced workload on a machinek and is a user defined value - L _j,k (S _p (j),n,a _i ) load of machinek at stagej when selection isS _p (j), number of part types isn, and number of parts of type isa _i - L* _j,k (S _p (j),n) load of machinek in stagej at minimum unbalanced workload when selection isS _p (j) and number of parts in system isn - F _j (S _p )(j),n,a _i ) unbalanced workload of all machines at stagej, when selection isS _p (j), number of part types isn, and number of parts of type isa _i - F _j (S _p (j),n) minimum unbalanced workload of all machines, whenS _p (j) is the set of selected part types andn is the number of parts in the system     

柔性制造系统机床选择建模研究

针对柔性制造系统(FlexlbleManufacturing System，FMS)机床选择模型构建及求解中存在的问题，以零件加工的时间目标作为模型的优化目标，以机床的购买成本作为约束，提出了FMS机床选择模型，结合遗传算法(GeneticAlgofitrm，GA)快速高效的搜索特性，对机床选择问题进行求解，并通过与现有的模型及其算法的求解结果进行比较分析，验证了本文提出的FMS机床选择模型及其遗传求解算法求解FMS机床选择问题的合理性和优越性。     

关于滚动轴承选型设计问题的研究

介绍了滚动轴承选型设计方法的发展，提出了根据滚动轴承系统可靠性与寿命要求和实际工况来完成组成系统各单元滚动轴承的选型设计的方法，使所选择的滚动轴承组成的系统在使用中满足系统的设计要求。     

An inexact algorithm for part input sequencing and scheduling with side constraints in FMS

Consider a flexible manufacturing system that produces parts of several types. The FMS consists of several groups of pooled, identical machines, a materials handling system, and a set of nonconsumable resources. Each type of part has its own unique sequence in the execution of the operations. An inexact algorithm is presented that sequences and schedules the input of the parts in the FMS by considering constraints such as machine availabilities and other resources in the machine groups, the availability of the transport units, and so on. Primarily, the goal of the algorithm is to minimize makespan and, secondarily, to minimize turnaround time. Several strategies are discussed, and the results are reported. A real-life problem is described.     

生产线规划的模块化研究

利用模块化设计思想,提出一种基于模块化的生产线规划方法。通过遗传算法对模块进行构建或重构。从而实现生产线的快速构建与重构,以适应市场产品多变的需求。     

A fuzzy grey goal programming approach for aggregate production planning

Aggregate planning is a medium-range capacity planning that suggests the production strategies in order to meet the forecasted demand considering the capacity constraints. As the period of planning length increases, the uncertainty of information will grow. Regarding this point, in this paper, a multi-objective model is proposed for aggregate planning problem in which the parameters of the model are expressed in the form of grey numbers. The suggested grey multi-objective model is solved based on a goal programming problem with fuzzy aspiration levels. The model is applied in a real-world problem, and its results are illustrated. The obtained results give a range for decision variables, and decision makers can handle the inevitable uncertainty of information by using these ranges.     

A polynomial time algorithm for production planning with bounded inventory

In petrochemical manufacturing, food processing, glass manufacturing, etc., there is a situation where the production planning is subject to the limit of inventory capacity (or bounded inventory) rather than production capacity. Only a few studies can be found in the literature for this situation. In this paper, the production planning problem with bounded inventory is discussed. Specifically, the problem considered had the following features: (i) backlogging is not allowed, (ii) lost sale is allowed, (iii) the lost sale cost function is time varying and non-increasing, and (iv) inventory capacity is non-decreasing. An algorithm for this problem with the polynomial O(T ³) time complexity is proposed. Though the complexity of the algorithm is the same as that of the other work, see Sandbothe and Thompson (Oper Res 38(3):474–486, 1990), the problem in the other’s work problem is less complex than ours; for instance only a fixed cost function is considered. A case study taken from a real-life production line is provided to further justify the application of the lost sale strategy, demonstrating the effectiveness of our model and algorithm.     

A mathematical model for production planning in hybrid manufacturing-remanufacturing systems

In recent years, environmental legislation, societal pressure, and economic opportunities have motivated many firms to integrate remanufacturing activities into the regular production environment. This presents many new challenges involving the collection, disassembly, refurbishing of used products, and incorporation of remanufacturing activities into new product manufacturing. In this paper, we present a mixed integer programming model addressing production planning problems in such hybrid systems. A Lagrangian decomposition based method is developed to solve the problem efficiently. A numerical example is presented to illustrate the proposed model and the developed solution procedure.     

Computer aided manufacturing planning for mass customization: part 2, automated setup planning

Setup planning plays a crucial role in CAPP to ensure product quality while maintaining acceptable manufacturing cost. The tasks of setup planning include identifying manufacturing features and corresponding manufacturing processes, determining the number of setups, part orientation, locating datum and process sequence in each setup, and selecting machine tools and fixtures. An automated setup planning technique and system has been developed based on not only the tolerance analysis, but also the manufacturing resource capability analysis. The automated setup planning is divided into two levels: setup planning in single part level and in machine station level. Algorithms for setup generation and process sequencing have been developed and a case study of setup planning is presented.     

基于仿真的生产系统规划技术研究

现代生产系统是复杂的离散制造系统,传统生产线的设计过多地依靠经验和手工演算,缺少科学性,很难达到预期结果.其中生产线的设计与生产线设备的利用率、产品的生产时间和生产线的效率等密切相关.采用先进的生产线规划与仿真技术,可以对生产系统的性能进行评价,在生产规划的早期对其系统进行优化与调整,以便得到较高的生产率.以某发动机缸盖的生产线的规划为对象,采用面向对象的离散系统仿真软件eM-Plant软件构建生产线仿真模型并进行了生产线生产能力、设备的利用率和生产效率的分析,为生产线的优化提供了技术依据.在此基础上采用生产线规划软件FactoryCAD构建了发动机缸盖生产线的3D数字模型,为发动机缸盖生产线的设计提供了技术依据.