Effective Production Control Research Articles

A Simulation Model for Spatial Scheduling of Dynamic Block Assembly in Shipbuilding

Accurately predicting the required spatial resource for aggregate block assembly in shipyard production is difficult due to the following reasons: 1) lack of optimal block on-jig configuration and 2) the dynamic and stochastic nature of production system. Consequently, managerial objectives are seldom achieved without effective production planning and control. In this study, a look-ahead scheduling mechanism with an application of discrete-event simulation is proposed to solve the dynamic spatial scheduling problem. A systematic simulation-based framework is suggested for validating schedules generated at high-level planning together with a heuristic-based optimizer for improving spatial resource utilization. Through imitation of the dynamic spatial operation under various priority rules, statistical analysis of resultant performance can be conducted to select the best performing control policy. A case study with computational experiments is performed and results are reported. Issues relevant to system implementation are highlighted as well.

Implementation of holonic scheduling and control in flow-line manufacturing systems: die-casting case study

The success of a flow-line manufacturing system depends on effective production scheduling and control. However, it has been found that current flow-line manufacturing scheduling and control algorithms lack the flexibility to handle interruptions or resource breakdowns; hence, system performance drops automatically and rapidly when interruptions occur. The objective of this research is to investigate if the performance of a flow-line manufacturing system can be improved by integrating agent-based, holonic scheduling and production control. A holonic manufacturing scheduling model has been developed and implemented into a die-casting manufacturing flow line throughout a simulation model. The analysis takes into account the comparisons of overall performances of the system models with the holonic scheduling and conventional scheduling approaches. Simulation results indicate that the holonic manufacturing scheduling and control can significantly increase the uptime efficiency and the production rate of the flow-line manufacturing system.

Fuzzy Bayesian reliability and availability analysis of production systems

To have effective production planning and control, it is necessary to calculate the reliability and availability of a production system as a whole. Considering only machine reliability in the calculations would most likely result unmet due dates. In this study, a new modelling approach for determining the reliability and availability of a production system is proposed by considering all the components of the system and their hierarchy in the system structure. Components of a production system are defined as production processes; components of the processes are defined as sub-processes. In this hierarchical structure we could model all kinds of failures such as material and supply, management and personnel, and machine and equipment. In the analysis, a fuzzy Bayesian method is used to quantify the uncertainties in the production environment. The suggested modelling approach is illustrated on an example. In the example, also a separate reliability and availability analysis is conducted which only considered machine failures, and the results of both analyses are compared.

Development and evaluation of a production planning, scheduling and control re-design Toolkit

Effective production planning, scheduling and control (PSC) is critical to any manufacturing business competing through responsive order fulfilment. With the current drive for businesses and supply chains to be responsive, a large scale empirical study was conducted with four cross-sector industrial partners to investigate the reality of PSC practice and to establish ways to improve it. From this in-depth analysis, design rules were established and used to develop a Toolkit to assist businesses in re-designing their PSC organisation and practice. This article describes the research and Toolkit development. It also evaluates the Toolkit and makes recommendations for future research.

Intelligent production control decision support system for flexible assembly lines

In this study, a production control problem on a flexible assembly line (FAL) with flexible operation assignment and variable operative efficiencies is investigated. A mathematical model of the production control problem is formulated with the consideration of the time-constant learning curve to deal with the change of operative efficiency in real-life production. An intelligent production control decision support (PCDS) system is developed, which is composed of a radio frequency identification technology-based data capture system, a PCDS model comprising a bi-level genetic optimization process and a heuristic operation routing rule is developed. Experimental results demonstrated that the proposed PCDS system could implement effective production control decision-making for solving the FAL.

Research on the WIP‐based Dispatching Rules for Photolithography Area in Wafer Fabrication Industries

Constructing an effective production control policy is the most important issue in wafer fabrication factories. Most of researches focus on the input regulations of wafer fabrication. Although many of these policies have been proven to be effective for wafer fabrication manufacturing, in practical, there is a need to help operators decide which lots should be pulled in the right time and to develop a systematic way to alleviate the long queues at the bottleneck workstation. The purpose of this study is to construct a photolithography workstation dispatching rule (PADR). This dispatching rule considers several characteristics of wafer fabrication and influential factors. Then utilize the weights and threshold values to design a hierarchical priority rule. A simulation model is also constructed to demonstrate the effect of the PADR dispatching rule. The PADR performs better in throughput, yield rate, and mean cycle time than FIFO (First‐In‐First‐Out) and SPT (Shortest Process Time).

CONWIP based control of a lamp assembly production line

Efficient and effective production control systems are very important for manufacturing plants. CONWIP, one of these production control systems, has a high potential of becoming the best one available because it suits a variety of production environments and is easy to implement. In the following paper, we compare the single-loop and multi-loop CONWIP production control systems for an actual lamp assembly production line producing different kinds of products with discrete distribution processing time and demand. A model is formulated with respect to total cost and service level. A novel rule-based genetic algorithm (GA) approach is proposed for the multi-loop CONWIP system to find the optimum parameter setting. The results have shown that the single-loop CONWIP production control system is more efficient than the multi-loop system. It can greatly decrease the total cost and the WIP (Work-In-Process) with zero shortage probability.

累積遅延に基づくリアクティブ・スケジューリング方策―単一機械動的スケジューリングへの適用

Reactive scheduling being discussed in the framework of dynamic scheduling is considered as an effective production control strategy in manufacturing systems. We have proposed a decision making model for reactive scheduling based on the critical number of delayed tasks which can be a measure to determine a suitable timing of schedule revision. In this paper, we propose a generalized policy called cumulative delay based reactive scheduling policy based on our previous work, which can be applicable to scheduling decision under a dynamic environment such as random job arrivals, changes of due date, and so on. Through some computational experiments, we examine not only basic properties but the effectiveness of the proposed policy by applying it to single-machine dynamic scheduling problems with sequence-dependent set-up, random machine breakdowns and underestimation of job processing times, where we minimize total set-ups as well as scheduling frequency. We also demonstrate that the proposed policy with even low scheduling frequency can outperform a typical event-driven rescheduling policy.

Transcriptional activation of the metallothionein I gene by electric pulses in vivo: basis for the development of a new gene switch system.

In vivo gene transfer to skeletal muscle is a promising strategy for the treatment of muscular disorders and for the systemic delivery of therapeutic proteins. Nevertheless, for a safe and effective protein production, the spatial and temporal control of gene expression is critical. The existing regulating systems rely on the use of an exogenously regulatory protein and/or an inducer drug whose pharmacological properties are of major concerns for therapeutic applications in humans. Therefore, new strategies based on endogenous regulatable elements have been explored. Gene expression profiles of skeletal muscle submitted or not to electrical pulses and harvested at different times were compared using the Affymetrix GeneChip technology. The endogenous metallothionein promoter was studied by Northern blot and semiquantitative and quantitative RT-PCR. The inducibility of the metallothionein I promoter placed in a plasmid exogenous context was studied using the murine SEAP reporter gene. The expression of metallothionein I mRNA is significantly increased 6 h after electric pulses delivery. This induction is transient. Identical MT-I expression level is observed after several sequential series of pulses delivery. We demonstrated as well that the MT-II promoter was sensitive to electric pulses delivery. Moreover, the metallothionein I promoter, placed in a plasmid context in front of a reporter gene, was also activated by the application of transient electric field. We identified a promoter highly inducible by the controlled electric stimuli applied for electrotransfer experiments. The use of the metallothionein promoter is promising for the time-control by physical stimuli of the expression of a therapeutic gene.

Holonic Concept Based Methodology for Part Routeing on Flexible Manufacturing Systems

A flexible manufacturing system (FMS) is designed to achieve good productivity and low cost. The success of an FMS depends largely on effective production scheduling and control. However, it has been found that current manufacturing scheduling and control algorithms lack the flexibility to handle interruptions or resource breakdowns; hence, system performance drops dramatically and abruptly when interruptions occur. This research develops a computer-simulation-based framework of FMS scheduling and control system using the holonic concept. This framework can maintain stability and flexibility while accommodating system disturbance, increase throughput, reduce part flow-time and work-in-process inventory, and balance workload among identical workstations. The significance of this research is the investigation of an innovative approach to revolutionary advances of control technologies for advanced manufacturing systems, and to the revitalisation of control and scheduling algorithms used by existing FMSs. A case study has been provided to substantiate the effectiveness of this proposed framework.

Business drivers not sector membership determine the most effective production planning and control; a novel approach to a perennial problem

This paper outlines research aimed at developing novel planning and scheduling reference models for industrial sectors where the MRPII paradigm is not appropriate. It outlines the process mapping approach adopted, the data capture method developed for the case study companies, the use of ARIS (Scheer's) enterprise modelling tool, and the first stages in the production of sector reference models.

A simulation study of kanban and CONWIP production control systems in a cold rolling plant

In order to get effective production control, different production control systems have been proposed. In this paper, the simulation study compares the CONWIP and Kanban system in an actual semi-continuous manufacturing plant, a cold rolling plant. Simulation results show that the CONWIP can greatly decrease the WIP(Work-in-Process), the average inventory and the average inventory cost, while hold the same throughput rate as that of Kanban system.

Distributed autonomous real-time planning and control of small to medium enterprises

The research reported in this paper is built on the use of the concepts of ‘holonic manufacturing’ and is seeking new methods to reinforce the autonomous and cooperative attributes of planning and control activities within human centred manufacturing facilities. It is claimed that in small enterprises, where the success depends on the skill of individual employees and their ability to collaborate, the manufacturing performance can be improved by the use of the appropriate information technology (IT) tools and the appropriate planning and control structure, designed and developed on the basis of these holonic concepts. Such novel tools and planning structures must provide the most appropriate information in a way that enhances collaborative activity within the business and strengthens the role of the individual. This paper identifies a number of major requirements that must be considered for the design and implementation of an effective production planning and control (PPC) structure, tailored for the needs of small enterprises. Based on these requirements and the use of holonic manufacturing concepts, a novel distributed autonomous real-time planning and control structure is presented. The final sections of the paper describe the implementation of such a planning and control structure within a typical configuration for the production facility of a small metalworking enterprise.

A prototype of a real-time support system in the scheduling of production systems

The success of a production system depends on effective production scheduling and control on the shop floor. There are advantages of using a human-computer interactive scheduling methodology. In this article, a prototype of real-time scheduling support system is developed based on a model of human behavior in scheduling tasks. By conducting an experiment, the total setup time and scheduling time of the subjects with and without support system (i.e., entirely manual method) are compared. In addition, a descriptive analysis of total setup time between four common dispatching rules and experimental data is presented. Through the experiment, some useful information about schedulers' experiences is summarized for further study.

A simulation and comparative study of the CONWIP, Kanban and MRP production control systems in a cold rolling plant

Effective production control systems are important for any manufacturing plant. In order to obtain effective production control, several different production control systems have been proposed. MRP, Kanban and CONWIP are the most popular systems among these. In this paper, a simulation analysis compares the three control systems implemented in a semi-continuous manufacturing environment: a cold rolling plant. Simulation results show usthat the CONWIP production control system is the most efficient of these. It can greatly decrease the WIP(Work-In-Process), average inventory and average inventory costs, while providing a higher throughput rate and facility utilization.

Shielding Production: Essential Step in Production Control

Effective production control systems are structured around the assignment as the unit of analysis. The quality of work assignments in production units such as construction crews and engineering squads is the key to production control and for determining production unit productivity. Research has revealed that the quality of assignments can be substantially improved by forming and selecting them to meet soundness, sequence, and size criteria. Quality assignments shield production units from work flow uncertainty, enabling those units to improve their own productivity, and also improve the productivity of the production units downstream. The associated reduction in task duration can shorten projects. Further reduction of project duration comes from shortening the buffers previously needed to accommodate flow uncertainty.

Production data modelling: an integrated approach

An effective production planning and control system requires combining the bill of material (BOM) and routeing data to reflect the material flow through the production process. Presents an integrated BOM and routeing data model which allows flexibility in handling relationships between materials and operations to suit specific needs. It can also be used as a standard data resource for creating production jobs. Maintaining job data independently of the BOM and routeing data allows the system to accommodate a wide range of production variations in practice. In a make‐to‐order environment, jobs are created for making line items on customer orders. To manage customer orders better, develops an extended job model to allow line items of a customer order to be made by one job. Perceives the concept of the extended job model as having considerable value in a wide range of production applications.

Approximation approach for the performance analysis of production lines under a kanban discipline

In a JIT production environment, pull-type control systems are usually implemented to reduce the lead time and to synchronize the production rate with the demand rate. The design of an effective production control system requires easy and reliable approaches for evaluating the effect of the major system parameters on its performance. In this paper we model the kanban control system of a manufacturing line as a Markov process. In addition, we develop an approximation approach to the model that permits reliable evaluation of manufacturing system performance in terms of throughput time and work-in-process. The validation of the approach is implemented by comparing the exact results (based on discrete event simulation) and the approximated results. A good approximation is observed for a large range of conditions.

The effectiveness of system integration in CIMS of Japanese companies

Under the present situation of diversification of users' needs, rapid technological innovation and internationalization, most Japanese manufacturers are required, as a management strategy, to develop an effective production system with small lot size and short production lead time. In order to meet these requirements, CIMS(computer-integrated manufacturing system) has been developed and introduced for practical use as a new computer-based production system. CIMS is characterized as an integrated system of software and hardware for production management with the purpose of meeting market requirements and counteracting fluctuations in users' demand by maintaining effective production planning and control. The style of CIMS varies with conditions of production and goals of system design. The purpose of this study is to investigate its effectiveness and examine future problems of system integration of CIMS in terms of production management in Japanese manufacturing companies.

Fourth generation languages based manufacturing control systems—lessons from an application case study

Abstract Fourth generation languages provide an attractive method for the development of flexible and adaptable software. In principle, it is feasible to create a core system software which is infinitely adaptable. However, there can be severe practical limitations and unforeseen consequences. This paper describes the practical implementation of a dedicated production planning and control system, for a machine tool company, based on the use of a fourth generation language based core software. The paper concludes with a discussion of the pitfalls which must be avoided to ensure smooth implementation of effective production planning and control systems based on flexible and adaptable software.