Showing papers in "Production Planning & Control in 1994"
TL;DR: In this article, a classification scheme is provided that is based on key factors such as the FMS type, the mode of system operation, the nature of the demands placed on the system, the scheduling environment, and the responsiveness of the system to disturbances.
Abstract: In this paper, existing flexible manufacturing system (FMS) scheduling procedures are classified and reviewed. First, a classification scheme is provided that is based on key factors such as the FMS type, the mode of system operation, the nature of the demands placed on the system, the scheduling environment, and the responsiveness of the system to disturbances. The choice of appropriate scheduling criteria is discussed. Differences between conventional job shops and FMSs, and the eiVects of these differences on potential scheduling procedures are provided. The classification, comparisons, and FMS scheduling reviews aim to be useful to vendors, users, and researchers. We point out specific areas which appear to have been overlooked. Future research directions are also indicated.
121 citations
TL;DR: In this article, the use of simple filter theory is proposed to help bridge the gap between simulation and design insights for the future of supply chain demand amplification in a three-echelon system, where there are factory, distributor and retailer activities.
Abstract: Recently, there has been a rebirth of interest in supply chain demand amplification, a trend accelerated by the availability of a wide range of simulation packages. However, although this approach provides some guidance on design improvements possible in a given situation, it rarely offers insight for the future. In the present paper the use of simple filter theory is proposed to help bridge this gap. The example chosen to illustrate the approach is a three-echelon system in which there are factory, distributor, and retailer activities. The results vividly confirm an optimal design previously obtained via a multi-attribute utility technique (MAUT) expert system. However, the knowledge gained via filter theory should improve yet further the effectiveness of the expert system. This is because the sequential steps to be followed when varying the echelon dynamics as part of the search procedure can be greatly improved. The paper concludes by showing how simulation results might be used to confirm the...
120 citations
TL;DR: An overview of research results in the domain of knowledge-based reactive scheduling and some related industrial applications is provided, and alternative knowledge-representation technologies and reasoning approaches which are often applied in real-time decision-making environments are examined.
Abstract: Reactive scheduling has emerged as a new concept in production planning and control over the past few years. It is attracting the increased interest of both academic and industrial researchers in developing available knowledge-based techniques in real-time shop floor control applications and providing advanced tools for subsequent industrial applications. In this paper, we provide an overview of research results in the domain of knowledge-based reactive scheduling and some related industrial applications. Since reactive scheduling is a new and not well-defined paradigm, we start by examining some definitions of the problem given by different practitioners in the field. We then examine alternative knowledge-representation technologies and reasoning approaches which, because of t heir flexibility and reactive capability, are often applied in real-time decision-making environments. This is followed by a review of some reported industrial applications, and a summary on major areas for further researc...
114 citations
TL;DR: In this article, the authors describe the principles of load-oriented manufacturing control as a new solution for job shops and its successful implementation in a pump-manufacturing factory, which is to limit and balance work-in-process inventory on a level as low as possible in order to accomplish a high work centre utilization as well as a rapid and in-time flow of orders.
Abstract: The paper describes the principles of load-oriented manufacturing control as a new solution for job shops and its successful implementation in a pump-manufacturing factory. The idea of load-oriented manufacturing control is to limit and balance work-in-process inventory on a level as low as possible in order to accomplish a high work-centre utilization as well as a rapid and in-time flow of orders. As the new system keeps actual lead times on a planned level in a self-regulating way, it allows reliable due-date scheduling. Furthermore it points out the bottlenecks and performs applicable mid-term and short-term capacity planning.
113 citations
TL;DR: Flexibility of manufacturing systems is currently under intensive study, and the need for objective measurement of this important characteristic is widely expressed as mentioned in this paper, where a survey of the literature dealing with quantification of certain types of flexibility, analyses the proposed measures, and presents critical views.
Abstract: Flexibility of manufacturing systems is currently under intensive study, and the need for objective measurement of this important characteristic is widely expressed. Measurement of manufacturing flexibility is being increasingly discussed in the literature on manufacturing systems. This paper surveys the literature dealing with quantification of certain types of flexibility, analyses the proposed measures, and presents critical views. Approaches to developing flexibility measures are compiled and classified. Discussion on the suitability of specific measures is provided. Requirements of flexibility measures and recommendations for future research in this area are also provided.
88 citations
TL;DR: In this paper, a heuristic model for deter mining the inventory replenishment policy for deteriorating items with time-proportional demand is proposed, which permits variation in both replenishment-cycle length and the size of the order.
Abstract: In this paper we propose a heuristic model for deter mining the inventory replenishment policy for deteriorating items with time-proportional demand. The heuristic permits variation in both replenishment-cycle length and the size of the order. Some numerical examples are given to illustrate the superiority of this heuristic.
69 citations
TL;DR: In this article, a survey of recent published work in the area of production planning and control, in the context of attempting to determine the extent to which it is likely to contribute to the needs of the user community, especially smaller manufacturing enterprises, is presented.
Abstract: This paper briefly reviews recent published work in the area of production planning and control, in the context of attempting to determine the extent to which it is likely to contribute to the needs of the user community, especially smaller manufacturing enterprises. A sample questionnaire survey is then described in detail. Its aims were to establish current practice and to identify factors which influence production planning and control and, especially scheduling, in real manufacturing organizations. This is supported by four mini-case descriptions. The paper concludes with a short discussion of an approach to bridging the gap between theory and practice, and to the development of software to support schedulers in smaller organizations.
35 citations
TL;DR: Period batch control (PBC) is a just-in-time (JIT) production control system of the flow control, single cycle type as mentioned in this paper, which was developed in the UK before the Second World War, by the late R. J. Gigli, who installed it in 30 different factories and used it to regulate the manufacture of Spitfire fighter aircraft for the Battle of Britain.
Abstract: Period batch control (PBC) is a just-in-time (JIT) production control system of the flow control, single cycle type. It was developed in the UK before the Second World War, by the late R. J. Gigli, who installed it in 30 different factories and used it to regulate the manufacture of Spitfire fighter aircraft for the Battle of Britain. Implosive industries are those—such as foundries, glass works, spinning mills and potteries, among others—which produce a wide variety of different products from a very small number of material items. The paper shows how PBC is used in implosive industries, and explains why it is normally the best method to adopt in such factories.
29 citations
TL;DR: In this paper, a dual-shuttle AS/RS operating under a nearest-neighbour scheduling model would significantly improve system throughput performance over a single-load shuttle system.
Abstract: Research to improve the performance of automated storage and retrieval systems has concentrated on developing more effective system designs or scheduling control programs to reduce the time a shuttle spends travelling in a rack. Sarker et al. (1991) showed that a dual-shuttle AS/RS operating under a nearest-neighbour scheduling model would significantly improve system throughput performance over a single-load shuttle system. The study was limited in that it only considered dual-shuttle improvements under the nearest-neighbour model. This research exploits the benefits of a dual-shuttle system by integrating the technology with a more effective scheduling technique, the class-based storage model, for reducing the shuttle travel time. The dual-shuttle, class-based storage model produced a significant reduction in shuttle travel time and thus higher throughput results over the dual-shuttle, nearest-neighbour model. This study further supports the premise that a dual-capacity shuttle is an effective ...
24 citations
TL;DR: The Shalibane Company of Camberley as discussed by the authors used Group Technology (GT) for tube manipulators and sheet metal workers, making parts mainly for the car industry, which was shown to promote growth and increase productivity, profitability and employment.
Abstract: Abstract. The Shalibane Company of Camberley are tube manipulators and sheet metal workers, making parts mainly for the car industry. In 1991 they introduced Group Technology (GT). In eighteen months they reduced stocks by 60% (still falling); increased sales and output by 33%; increased the rate of return on investment by 24%; and increased the number of their employees by 12%. The cost of introducing the change was covered more than 3 times by the reduction in the stock investment. GT is shown to be a method which promotes growth and increases productivity, profitability and employment.
17 citations
TL;DR: This paper reviews the concepts and applications of neural networks as they relate to various aspects of manufacturing management and suggests several approaches that can be used in manufacturing management.
Abstract: Abstract. The inherent complexities of modern manufacturing require more sophisticated systems for their management. Neural networks, which are massively parallel interconnected networks, have been shown to have extensive applications in various systems that can be used in manufacturing management. An extensive amount of literature has been published on the applications of neural networks in manufacturing, yet no comprehensive review of this literature to date has been offered. In this paper, we review the concepts and applications of neural networks as they relate to various aspects of manufacturing management.
TL;DR: In this paper, several measures of the backtracking of materials are developed to assess the degree to which a configuration approaches the generalized flow line (GFL) of a job-shop configuration.
Abstract: In many modern manufacturing settings, management simplifies the workflow of jobs to the greatest extent possible by avoiding a job-shop structure in favour of a generalized flow line (GFL) in which all jobs flow in a single direction (Conway et al., 1967, Theory of Scheduling (Addison-Wcsley)). Heuristics may be used to assign machines to appropriate locations in the attempt to achieve a GFL. Materials that must be transported upstream in a production line are said to ‘backtrack’. Since no backtracking occurs in a GFL, the relative amount of backtracking that does occur is an indication of the degree to which the ideal (and most productive) case is achieved. Several measures of the backtracking of materials are developed in this paper to assess the degree to which a configuration approaches the GFL. The measure for backtracking is extended to bi-directional flow problems which may occur when a GFL is not achievable because of the job routing.
TL;DR: In this article, the authors present a methodology which uses design and manufacturing attributes to form manufacturing cells in a computer integrated manufacturing setting, where parts are grouped into part families based on their part families using an optimization technique.
Abstract: The primary objectives in implementing computer integrated manufacturing systems (CIMS) are to improve quality, enhance flexibility, and increase productivity. One of the approaches used to achieve these objectives is to organize and group the production machines into manufacturing cells using group technology concepts. Cellular manufacturing allows small batch production to gain economic advantages similar to mass production while maintaining the flexibility of job shop production. This paper presents a methodology which uses design and manufacturing attributes to form manufacturing cells in a computer integrated manufacturing setting. The methodology is implemented in two phases. In phase I, parts are grouped into part families based on their design and manufacturing attributes. In phase II of the methodology, the machines are grouped into manufacturing cells based on relevant operational costs, and the various cells are assigned part families using an optimization technique. The optimization t...
TL;DR: In this paper, the authors outline a practical theory of a situational approach to production management, which is seen as a dialogue between identification of the production management task and specifying a solution system.
Abstract: Discussions in journals and at conferences often nurture the dream of the ultimate method which may be applied successfully to all situations. Yet everybody knows that ‘it all depends’ and that situational factors determine which methods and systems are appropriate. This paper sets forth to outline a practical theory of a situational approach to production management. Any improvement of production management is seen as a dialogue between identification of the production management task, on the one hand, and specifying a solution system, on the other. A few concepts are introduced to provide practical methods for carrying out an improvement process; in particular, the nature of the production management task is addressed. The implications of the situational theory to be presented are discussed for three levels of application, respectively, the general level, the industry level, and the level of an individual industrial enterprise. It is further argued that the three levels are interdependent and t...
TL;DR: In this paper, a comprehensive model is presented to show the critical linkage between just-in-time (JIT) and HRM, and the impact of US labour laws on HRM practices is discussed and contrasted with Japanese practices.
Abstract: Successful just-in-time (JIT) implementation requires a multiskilled group-oriented and self-disciplined workforce with good quantitative skills. Little discussion exists in the JIT literature concerning the development of such a workforce. The human resource management (HRM) literature deals with employee issues but does not identify strategies for achieving a JIT workforce. In order to identify appropriate HRM strategies for a JIT environment, a comprehensive model is presented to show the critical linkage between JIT and HRM. Interactions between legal issues, management and union, and human input are examined. The impact of US labour laws on HRM practices is discussed and contrasted with Japanese practices. The literature review of HRM-related JIT articles suggests that HRM practices in the areas of staffing, training and development, compensation, and employee retention can be used to develop an effective JIT workforce. The article will help production managers to understand the impact of sp...
TL;DR: A production system organized in parallel multiproduct manufacturing lines is presented and a classification given of the essential constraints which characterize this type of system.
Abstract: The systems discussed in this work concern a wide range of production systems in industry; notably in the pharmaceutical, chemical, cosmetic, food and brewing industries. A production system organized in parallel multiproduct manufacturing lines is presented and a classification given of the essential constraints which characterize this type of system. Also given is a classification of the different pieces of knowledge and data necessary for the planning and scheduling development. The knowledge acquisition phase is discussed and a classification of rules given. Each kind of rule is illustrated by an example. The scheduling algorithm is given, and illustrated by a demonstrative example in order to highlight the methodology used. In the last part, the prototype developed with an industrial partner is presented and the results discussed according to the given evaluation criteria.
TL;DR: In this paper, a design for decision support is presented to integrate and give feedback to the responsible material planner to measure the performance, the frequency of process disturbances and the effect of the parameters on performance for all commodities involved.
Abstract: Control parameters, such as order frequency, safety stock and safety time, are important tools to improve the logistic performance in material planning. In practice, the adjustment of control parameters appears to be very difficult. One of the reasons is the lack of relevant tactical control information: a simple, periodical and per-commodity integrated feedback of performance and process information often is not available to the logistic operator. Therefore, the material planner is offered a fairly limited overview and insight of the processes to be controlled. This problem has been investigated in several plants in the Netherlands. A solution to this problem is first to measure the performance, the frequency of process disturbances and the effect of the parameters on performance for all commodities involved. And second, to integrate this information and provide feedback to the responsible material planner. In this article a design for decision support is presented to integrate and give feedback...
TL;DR: In this article, the optimal operation planning of a fixed interval withdrawal Kanban with variable lead times is proposed, where a cost is incurred for inventory level less than the safety inventory level, since the risk of shortage of inventory must be considered.
Abstract: In the majority of the previous research on Kanban systems delivery lead time is treated as a fixed value. In many practical situations, however, the lead time is variable. In this paper, optimal operation planning of a fixed interval withdrawal Kanban with variable lead times is proposed. A cost is incurred for inventory level less than the safety inventory level, since the risk of shortage of inventory must be considered. Behaviour of the optimal number of Kanbans and the withdrawal interval of Kanbans are investigated in terms of various parameters such as standard deviation and mean lead time.
TL;DR: In this paper, a simple model, trial-and-error on a spreadsheet, was used to produce cost-effective production planning solutions, and the results indicated that good solutions can be obtained using this method.
Abstract: Firms can benefit by developing and using aggregate production plans. However, reports of ongoing production planning applications are rare. The complexity of production planning models has been cited as one of the reasons that firms do not develop formal production plans. This study was conducted to determine if a simple model, trial-and-error on a spreadsheet, could be used to produce cost-effective production planning solutions. Results indicate that good solutions can be obtained using this method. Furthermore, solutions tend to improve as the knowledge of the production planner increases and as time spent developing solutions increases. In addition, experience at producing spreadsheet-based solutions can translate into lower cost solutions for more complex problems while using less time for analysis. These findings indicate that spreadsheets can be effective decision aids for developing production planning solutions. By coupling the power and simplicity of a spreadsheet modelling package wit...
TL;DR: In this paper, a graphical interpretation of the counterbalancing method is presented, which reveals the need for variable as opposed to fixed equal weights, resulting in further reductions in forecasting error.
Abstract: Abstract. Counterbalancing is a new method of forecasting that reduces the systematic component of forecasting error. A graphical interpretation of the method is presented. This intuitive approach reveals the need for variable as opposed to fixed equal weights. The method is expanded to counterbalancing with variable weights, resulting in further reductions in forecasting error. Important applications include (1) power system hourly load forecasting for economic dispatch, (2) information feed forward in continuous process control, and (3) forecasting for scheduling, just in time manufacturing, sales, and distribution requirements planning in global logistics.
TL;DR: In this article, a simple and practical heuristic to the slow-moving items problem is presented, which is based on the classical models in stochastic inventory theory, and an analysis of the simulation results is presented.
Abstract: Abstract. The traditional approach in the study of inventory systems is to give more importance to items whose demands are either large or very difficult to forecast, discounting the importance of inventory items with small demand. The objective of this paper is to present a simple and practical heuristic to the slow-moving items problem. First we provide insight into previous work in this area and also give a brief outline of classical models in stochastic inventory theory. Then we present the proposed approach and detail the heuristic. We summarize the paper with an analysis of the simulation results and finish with the conclusions that are drawn from the results.
TL;DR: In this paper, the problem of lot scheduling for multiple items processed in the shop with either a single machine or heterogeneous machines is considered, under the condition that parts to be processed must arrive at the production line at the right times in the right quantities, and that completed parts must be delivered at their due date.
Abstract: Abstract. This paper deals with lot scheduling problems of multiple items processed in the shop with either a single machine or heterogeneous machines, under the condition that parts to be processed must arrive at the production line at the right times in the right quantities, and that completed parts must be delivered at their due date. Each of the problems is divided into subproblems of lot sizing and scheduling the resulting lots. Solution procedures solving the subproblems are separately optimal. However, since one of the subproblems is not independent of the other, the proposed algorithms adopting these procedures are to be considered heuristic. An iterative procedure is provided to improve solutions. The performance measure used is that of minimizing the total actual flow time considering both receiving just in time and delivery just in time. Numerical examples are presented to show the implementation of the algorithms.
TL;DR: In this paper, the authors present a methodology for assisting managers in the selection process of procurement methods, which considers the annual usage value, lead time ratio, holding cost, vendor location, vendor delivery performance, and material supply value.
Abstract: In designing mechanisms for the procurement of raw materials, a manager is often faced with the task of selecting from a variety of possible methods. Since the performance of these methods is a function of the environment in which they are implemented, it is the responsibility of the manager to select the method best suited for a particular application. In this paper we present a methodology for assisting managers in the selection process. Specifically, three classes of procurement methods are considered, these are: demand based, reorder, and JIT methods. The selection methodology is structured as a decision tree, which considers the annual usage value, lead time ratio, holding cost, vendor location, vendor delivery performance, and material supply value. Each factor is evaluated on a three level scale, and on the basis of these evaluations the tree makes a selection. The application of the methodology is illustrated via some examples.
TL;DR: In this paper, the authors present the results of a large-scale computer simulation of 12 of the standard single-level, discrete demand lot sizing heuristics on 15 individual demand patterns.
Abstract: This paper presents the results of a large-scale computer simulation of 12 of the standard single-level, discrete demand lot sizing heuristics. The authors present the results in 3-D illustrations which depict the performance of these heuristics on 15 individual demand patterns. This information is prefaced by a brief review of the method used to perform the simulation. The performance of each of the 12 heuristics was evaluated for 51 sets of cost parameters for each of 15 different demand patterns. This has resulted in the analysis of 9180 combinations of heuristic, demand pattern, and cost parameters. The authors believe that this, by far, represents the largest digital simulation of single-level lot sizing rules completed to date. During the past two decades, a significant amount of research investigating the economics of lot sizing single-level discrete demand patterns has been conducted. However, many of the conclusions reached by individual research efforts on this subject have differed. At...
TL;DR: In this paper, two solution approaches, one based on a location model, the other on simulated annealing, are presented and compared along with test results, and the location formulation, which results in an integer programming model solved by Lagrangian relaxation, proved capable of producing solutions of excellent quality, but only for relatively small problem instances.
Abstract: In the production planning and control of discrete-parts manufacture, aggregation of parts into families, on the basis of similarity, is carried out to ease both long-horizon planning and short-horizon scheduling. Additional advantages are related to those of group technology (GT), such as simplifying the flow of parts and tools and reducing both set-up and production costs. The problem of formally forming part families is presented and discussed. Previous work is reviewed and assessed. Two solution approaches, one based on a location model, the other on simulated annealing, are presented and compared along with test results. The location formulation, which results in an integer programming model solved by Lagrangian relaxation, proved capable of producing solutions of excellent quality, but only for relatively small problem instances. In contrast, simulated annealing, which is a general heuristic approach to combinatorial optimization, produced solutions of comparable quality and could handle re...
TL;DR: In this article, the effects of four simple dispatching rules on just-in-time production related performance measures of mean and maximum absolute lateness were investigated, and the results indicated that each rule performs well under certain conditions.
Abstract: Abstract. This paper investigates the effects of four simple dispatching rules on just-in-time production related performance measures of mean and maximum absolute lateness. The rules used are modified due date (MDD), shortest processing time (SPT), earliest due date (EDD), and first in first out (FIFO). A single machine is used under three utilization levels. Due-dates are set according to total work content rule. The results indicate that each rule performs well under certain conditions. The MDD rule is the best one to minimize mean absolute lateness. The EDD and FIFO rules do well in minimizing the maximum absolute lateness. Economic interpretation of these performance measures are also discussed.
TL;DR: In this article, the authors considered an inventory model where the ordering cost depends on the size of the lot and increases in steps as the lot size increases, and developed an algorithm to determine the economic order quantity.
Abstract: The classical Harris - Wilson inventory model assumes that the ordering cost is constant and does not depend on the quantity ordered. There are, however, many practical situations where this is not true. This paper considers an inventory model where the ordering cost depends on the size of the lot and increases in steps as the lot size increases. An algorithm is developed to determine the economic order quantity and is illustrated by a numerical example.
TL;DR: In this article, goal programming (GP) is applied to a real-world JIT problem involving fabrication of different automotive and industrial rubber composite belts and the model results provide new insights concerning the conflicting nature of several goals, especially between meeting demand and reducing setup or idle time.
Abstract: The just-in-time (JIT) system has been studied extensively and implemented by a number of US firms as an ell'ective production system The core of JIT involves determination of lot size and setup time reduction so as to increase manufacturing flexibility while minimizing the inventory level This decision problem usually involves multiple conflicting objectives and mixed-model production In this paper, goal programming (GP) is applied to a real-world JIT problem involving fabrication of different automotive and industrial rubber composite belts The model results provide new insights concerning the conflicting nature of several goals, especially between meeting demand and reducing setup or idle time Also, the GP solution is superior to the current JIT practice of the company