Scheduling a manufacturing process with restrictions on resource availability

This paper examines the scheduling of a drug packaging operation which requires assigning resources to production lines during set-up in order to satisfy product specifications. We present mixed integer programming models of the problem and develop a Lagrangian heuristic to solve the models. Real data from a drug company and randomly generated data are used to test the models. Results show the efficacy of our solution approach to find good feasible schedules. We discuss some of the practical benefits and potential issues about the production schedules obtained using the models.     

Network-integrated manufacturing system

In this study, systematic integration for networked manufacturing, including information integration, process integration, knowledge integration and organisation integration, is presented. Then, a model of network-integrated manufacturing system (NIMS) is proposed. A wheel of network-integrated manufacturing system (NIMS) details the concept, which includes five integrated rings: the rings of core objects, participants, support centres, functional subsystems and infrastructure. A NIMS model of a Chinese ceramic company (CP-NIMS) is presented to illustrate how the model can be applied to ceramic product design, customisation, production, and delivery.     

Delayed reconfigurable manufacturing system

Reconfigurable manufacturing systems (RMS) is a new manufacturing paradigm aiming at providing exactly functionality and capacity needed and exactly when needed. Reconfiguration is the main method to achieve this goal. But, the reconfiguration is an interruption to production activities causing production loss and system ramp-up problem and the ‘exact functionality’ may increase the reconfiguration efforts and aggravate the production loss and the ramp-up time. Therefore, a special RMS – delayed reconfigurable manufacturing system (D-RMS) is proposed to promote the practicality of RMS. Starting from the RMS built around part family with the characteristic of delayed differentiation, whose reconfiguration activities mainly occur in the latter stages of manufacturing system and the former stages have the potential to maintain partial production activities to reduce production loss during reconfiguration. Inspired from this, the basic structure of RMS is divided into two subsystems, subsystem 1 is capable of maintain partial production with a certain more functionality than needed, subsystem 2 reconfigure to provide exactly functionality and capacity of a specific part exactly when needed. And then, the benefits of D-RMS are analysed from inventory and ramp-up time aspects. Finally, a case study is presented to show the implementation process of D-RMS and validates the practicability of D-RMS.     

Loading a flexible manufacturing system

This paper examines the problem of master scheduling for an FMS in Scotland containing six CNC horizontal boring machines. A multiple criteria approach is used to choose the compatible subset of candidate orders for processing by this FMS, subject to resource constraints and potentially conflicting performance objectives. A structured framework for conflict resolution is described and compromise solutions are obtained using standard mathematical programming software.     

Introducing a flexible manufacturing system

Flexible Manufacturing Systems represent a significant investment and their introduction involves a major project for a company. This paper refers to the introduction of FMS in a company. It discusses various management aspects of the project, and its main subject is the simulation modelling of the system. The objectives of the simulation studies are given and the model described. Results are given and commented on, whereby certain capacity limitations were identified. As a result of the studies, weaknesses in the supplier's control software were highlighted and modifications made.     

Two-level manufacturing system performance analyser

Open queuing network is a commonly used analytical tool for modelling manufacturing systems. Parametric decomposition is a proven solution method for analysing open queuing networks and can estimate key performance measures such as work-in-process inventory, cycle time, and machine utilisation, fairly accurately. This paper presents a two-level hierarchical open queuing network model, which considers numerous features seen in a real manufacturing system including, machine set-up, material handling device setup (for example, loading and unloading operations), process as well as transfer batching, empty travel of the material handling device and machine or material handling device failures. The model first analyses a higher level open queuing network whose nodes are aggregations of a set of machines. The higher level network is solved via the parametric decomposition method and the results are then disaggregated to get lower level, e.g. machine specific, results. The motivation, algorithm and its relationship with the one-level model are discussed. Experimental results are provided to show that the two-level model provides comparable results with the one-level model in addition to its computational and managerial advantages. In addition, both are shown to provide better results than a recent method available in the literature that is based on the well-known queuing network analyser.     

Just-in-time manufacturing system: a periodic pull system

The just-in-time manufacturing system, as developed in the Toyota Motor Co., may be stated as producing or stocking ‘only the necessary items in necessary quantities at the necessary time’. When the just-in-time concept is applied to an industrial material management system, it is called a pull system, which means that the amount and time of material flow are determined by the rate and time of the actual stock consumption. Actually, in Toyota, this pull system is operated manually by means of a kanban, a sort of card or tag.

As an alternative to a kanban method, a periodic pull system (PPS) is developed as an operating policy of practising a Pull system. Due to the fact that, in a PPS, the manual information processing time of a kanban method is replaced with an instant on-line computerized processing, the material lead time is much shorter than that of a kanban system. This results in better system performance such as less lead time inventory and faster system response.

A PPS is formulated mathematically and a solution approach is provided for target stock levels, as well as the analysis of the fluctuations of in-process material flow, on-hand stock levels, target availability, etc.     

A generative system for re-engineering manufacturing system organization

The target organization of a problematic business process is the one that is completely focused on the target market, whereas the organizational change plan is the set of intermediary organizations that lead to a satisfactory organization close to the target organization. Organizational re-engineering includes the identification of the target organization and the design of the organizational change plan for a problematic business process. Current re-engineering methodologies do not use fuzzy cognitive maps for identifying the target organization or formal tools for designing the organizational change plan. This paper presents a new CAD system that supports organizational re-engineering. This system includes fuzzy cognitive maps that identify the target organization using industry knowledge and feedback control models that support the design of the organizational change plan by adapting the target organization to the current reality of the firm. The organizational change plan can be corrected during the implementation of the organizational changes because it is expressed as a function of the state of the problematic system. The suggested CAD system is applied to re-engineer the setup operations of a problematic press.     

Multiagent-based modeling for re-entrant manufacturing system

Re-entrant flow manufacturing system is a typical mix of different process types, sequence-dependent setup times, very expensive equipment, and re-entrant flows. A multiagent-based modeling technology for re-entrant manufacturing system was addressed. The model of Agent-based Colored Timed Petri-Net (ACTPN) is constructed, which consists of the material flow net model and the interactive protocol model. In the material flow net, the interior behavior of machine agent was encapsulated and it was separated into the system layer, machine group layer and machine agent layer to form a hierarchical multiagent-based model, which reduced the complexity and improved the reusability of the model. In the view of modeling methodology of the interactive protocol net, the transforming rule from Agent Unified Modeling Language (AUML) to ACTPN was given so as to map the AUML model to ACTPN model. In the view of the analysis method of the interactive protocol net, it was integrated with a reachability graph to check the liveness and bound properties of interactive protocol model. A distributed discrete event simulation platform to evaluate the performance of the multiagent-based re-entrant manufacturing system was built. An illustrative example of a 6-inch semiconductor fabrication line in Shanghai demonstrates the effectiveness of the approach proposed.     

多单元制造系统布局设计

从布局设计的角度,提出多单元制造系统的概念,把各种制造系统的布局问题转化为多单元制造系统布局设计问题,包括设备布局和制造单元布局两个方面。对于设备布局问题,给出一种优化建模与虚拟现实技术相结合的求解策略;对于单元布局问题,给出一种集成的布局设计方法。     

双重资源约束条件下制造系统的调度

 根据近年来关于制造系统优化调度问题的研究状况，阐述了具有计算智能的方法，特别是遗传算法在调度问题研究中的应用． 指出同时考虑设备和工人两种资源限制的双重资源约束条件是很重要的，提出了一种混合调度原理和方法．     

A lean-based ORR system for non-repetitive manufacturing

Lean implementations are no longer limited to high-volume production and are becoming increasingly common in low-volume, high-variety non-repetitive companies. Such companies, usually with make-to-order or engineer-to-order production, have normally been modelled with a job shop production system, but many of them actually have a dominant flow in production. Moreover, one of the main characteristics of lean implementation is that it streamlines production flow, makes it unidirectional and reduces setup and lot size. Consequently, a significant number of production systems are better modelled as flow shops, rather than as job shops. This has an impact on production management approaches, and in particular on order review and release systems. In fact, ORR systems have been designed with job shops in mind, because they are the most complex systems to manage, and because they are considered the optimal system for non-repetitive production. We believe that job shop designed ORR systems are not the best ones for flow shop systems. We consequently propose a new ORR system designed for non-repetitive production in flow shops and based on lean principles. The simulation campaign run to test the new model shows that it yields lower lead times and increases output.     

The tooling system configuration in a new manufacturing system architecture

A new manufacturing system architecture, called Mod Flex Prod (MFP), has been recently proposed to match the balance between productivity and flexibility required by suppliers of components for the automotive industry. Among the relevant issues that cause the new architecture to be more profitable than transfer lines and flexible manufacturing systems, tooling has been shown to have an important role. Starting from this result, this paper deepens the advantages in tooling attainable with the new architecture. In particular, it presents a new approach for configuring the tooling system (i.e. selecting the number of tool copies for each tool type) which takes into account that tool copies can be required by the machines to perform operations, by the tool carrier to transport tools within the system and by the tool room when inserts have to be reconditioned. With reference to a real case study, the new approach allows one to assess that tooling investment can be reduced by about 20% if the new architecture replaces traditional flexible manufacturing systems.     

Novel approach to multi-channel manufacturing system design

Volatile market conditions have made classical production organizations obsolete in the 1990s. Therefore, new means such as holonic, fractal and multi-channel production systems are investigated to enhance manufacturers' dynamic response ability and competitiveness. Amongst these, newly suggested multi-channel manufacturing (MCM) systems compromise compatibility and specialization to produce a certain range of products. This study proposes a new approach based on genetic algorithms to devise such production channels. Feasible solutions corresponding to machine sequences for channels are coded as chromosome structures. Applying genetic operations to these chromosomes created improved arrangements regarding a problem given in the literature. Furthermore, an effective and realistic solution for a real life problem was found by making use of the multi-objective fitness function developed.     

Towards a psychologically consistent cellular manufacturing system

In cellular manufacturing systems (CMSs), an operator plays an important role. Because operators work for long-time periods in a production area, an increase in job satisfaction and system productivity occurs if the consistency of operators’ personal characteristics are considered in the design of CMSs. In a CMS, a cell formation problem (CFP) focuses on grouping and allocating machines, part families and operators to manufacturing cells. This paper considers a decision-making style (DMS) as an operator’s personal characteristic index in a CFP for designing a psychologically consistent CMS. DMS influences not only the interaction between two operators, but also the work that operator does on a machine. Hence, this paper develops a novel multi-objective mathematical model for the CFP considering consistency between each two operators in each cell and consistency between operator and his/her assigned machine(s). Because of possibility of a change in the primary DMS of a person to the backup one, this paper tackles this issue by applying a probabilistic procedure. Two hybrid meta-heuristic algorithms are developed for the large-sized test problems. In addition, the PROMETHEE-II method is applied to select the best Pareto solution. Finally, a real case study is presented to show the applicability of the developed approach.     

Goal-orientation mechanism in a fractal manufacturing system

Decomposition of tasks in ordinary manufacturing systems is usually based on the predefined goal of the system. To achieve the high-level goals (e.g. factory goal or company goal), several subgoals should be achieved in advance. However, goals can dynamically change along with the current status of the system and the external environmental situations. Thus, a manufacturing system should support the goal formations, which can bear these changes for efficient and effective operations. Therefore, it is necessary to develop a systematic methodology for goal formations in a manufacturing system. In particular, the formation and/or change of goals in real-time should be possible for distributed and dynamic systems including a fractal manufacturing system (FrMS). However, most researchers have started their study from an assumption that every goal in the system is naturally well defined. This paper proposes a methodology for the goal-formation process (GFP), which embodies one of the characteristics of a fractal (i.e. goal orientation) in the FrMS. In order to generate fuzzy goals and propagate them in the system, fuzzification/defuzzification and goal-generation procedures are presented in detail. For easy understanding of the procedure, an exemplary goal generation is also illustrated within the proposed GFP framework. By applying the GFP, we expect that the manufacturing system would become autonomous and flexible by generating and evolving goals without human intervention.     

Estimation of repairable system availability within fixed time horizon

The paper presents an efficient approach to estimating the availability of a repairable system observed within a fixed time horizon, which is regarded as a random variable over range [0,1]. A Beta distribution based approximation of this characteristic is proposed. The presented results are derived from Monte Carlo simulation and statistical analysis of the simulation results. Numerical examples are also provided to illustrate the practical impact of this approach.     

FMS Designer: An expert system for flexible manufacturing system design

Implementation of flexible manufacturing technology in the batch manufacturing environment has created major problems for designers and engineers who are responsible for specification and design of flexible manufacturing systems (FMS). The FMS design task appears to be an excellent application for expert systems techniques. This paper describes current results of an ongoing research effort to develop an expert system which analyses the output from an FMS simulation model, determines whether operational and financial objectives are met, identifies design deficiencies or opportunities for improvement, and proposes designs which overcome deficiencies or exploit improvement opportunities. An overview of the FMS design expert system is given and a case study is presented to illustrate how the system operates. Areas for future research are also discussed.     

An intelligent cell control system for automated manufacturing

Cell control forms one level of a hierarchical approach to the control of automated manufacturing systems. This paper describes the application of the artificial intelligence techniques of blackboard and actor based systems for intelligent cell control in a framework termed Production Logistics and Timings Organizer (PLATO-Z). The blackboards required are described and the implementation is detailed. The implications of some practical considerations are also described.     

A scheduling approach for a flexible manufacturing system

This paper discusses the scheduling problem of a particular flexible manufacturing system (FMS). The two main components of the FMS are a CNC turret lathe and a CNC machining centre. In the system a wide range of different jobs has to be processed. Each job consists of one or more processing operations on one or both machines. Important characteristics of the scheduling problem are sequence-dependent change-over times (on the turret lathe) and transfer times (on both machines and between the machines). The change-over times are caused by the need to exchange tools in the turret when a new part is going to be processed. The transfer times reflect the time needed to perform manual transportation and clamping activities between two subsequent processing (machining) operations of a part. In this paper a branch and bound algorithm is described based on an active schedule strategy. Solutions are compared to results obtained by a simple dispatching rule