Implementation of continuous flow manufacturing (CFM) system

In a world of global competition and demanding customers, putting production requirements ahead of customer's needs inevitably leads to manufacturing inefficiencies, higher inventories, and poor quality goods and services. In continuous flow manufacturing (CFM) system, the manufacturer makes how much and what is needed, and also when it is needed. A leading multinational company in oral care products produces toothbrushes through contract manufacturers (CMs). The contract manufacturer makes different stock-keeping units (SKUs) under two options: (i) the contract manufacturing option, in which CM supplies the finished products; (ii) the labour contract, in which CM is responsible only for conversion. Competitive pressure in the market pressures the company to change the operating system from the push system to CFM for CMs also. Moving from the push system with its high level of inventories to continuous flow manufacturing system enables the achievement of improved customer responsiveness, greater efficiencies, lower inventories and lower operating costs. This paper describes the way in which one such contract manufacturer was moved towards the CFM system and the benefits achieved through it.     

Reviewers

This paper reports the findings of a research study into the application of lean production methods to a traditional aerospace manufacturing organization. The approach taken to lean production is described, along with what worked and what did not. Two main stumbling blocks to the application were identified the redundancy programme and a lack of employee education in the concept and principles of lean production. A number of the methods of lean production were found not to be as effective as in the motor manufacturing environment, the reasons for this included the dominant position of the company and the customer demand characteristics. In addition, both management and the industrial workers found the transition from traditional manufacture to lean production was not easy to make.     

Selection of methods,techniques and tools for system analysis and for the integration of CIM-elements in existing manufacturing organizations

Abstract

Implementation of computer-aided and integrated manufacturing systems requires one to consider all areas of the company in order to ensure a homogeneous and continuous evolutionary system development. Therefore, planners of computer integrated manufacturing (CIM) systems need a concept to come to a coherent selection of methods for those system development. In this paper a concept is introduced which allows an interdisciplinary team of system developers (engineers, industrial economists, personnel economists) a coherent choice of methods for system development. As examples, three methods applicable to the problem of CIM-implementation into organizations are evaluated.     

Decentralized WIP-oriented manufacturing control (DEWIP)

DEWIP is a manufacturing control system for job shop environments aiming at achieving short and reliable lead times by establishing WIP control loops between the manufacturing work centres. The paper describes the mode of function, the setting of parameters and simulation results of the new manufacturing control system. The setting of parameters is done with the aid of the funnel model and the theory of logistic operating curves, both developed at the Institute of Production Systems at the University of Hanover. The simulation is conducted using industrial data and makes it possible to assess DEWIP with regard to lead times, WIP level, performance and schedule reliability. DEWIP is compared both with an uncontrolled process and with the manufacturing control systems Load oriented order release (LOOR), Conwip and Polca. The results suggest that DEWIP and the models employed for the setting of parameters are suitable for job shop production and therefore offer a valuable alternative to prevailing centralized manufacturing control systems.     

Survey of resource allocation methods for distributed manufacturing systems

Distributed manufacturing systems are more flexible in their arrangement and use of their resources. This permits a more dynamic and opportunistic allocation of manufacturing resources to work elements than is possible with today's centralized allocation systems. However, unlike solving the problem from a single solver view, there is no absolute control or tight coordination over how and when to decompose the problem, when to undertake a solution or the procedure for verifying consistency. Such activities will largely be left to the distributed entities to decide either individually or jointly. As a consequence the resulting allocations may suffer and induce myopic behaviour lacking in stability and regularity in the performance of the total system. Thus, the issues connected with solving the problem often move beyond the pure algorithmic focus of computation to include how the problem is decomposed, how or to whom it is assigned, and the organization for solving the subproblems, strategies used for resolving conflicts, the manner in which communication is conducted, etc. These issues, in fact, highlight the holistic nature of the solution and are used here as parameters to compare and contrast the approaches reported in the literature.     

Production planning and inventory control in a company manufacturing PC parts: A case study

In this paper, we present a case study on the production planning and inventory system in a company manufacturing personal computer (PC) parts. In the case study, the targets are specified for developing a system for production planning and inventory control. The current state of the company is analysed for clarifying the points necessary to achieve the targets. Also, a system based on the analysis is proposed and its effects are estimated.     

Engineering change: A theoretical assessment and a case study

The competitive playground where nowadays firms struggle to survive has rapidly become unforeseeable: product life cycle has shrunk, becoming even shorter than in the past, and world-wide market is suffering for a strong customer differentiation which led to an increasingly wide product mix. In this industrial environment, the engineering change process is getting more and more attention throughout the branches of industry, as it appears as a critical process which seeps into the operations management core, thus influencing the overall firm's performances. A brief state-of-the-art in the area of engineering change is firstly presented. Then a proposal of classification and a new methodology for an effective engineering change process management are suggested. The new proposed methodology has been successfully applied to a real-life manufacturing system and the related case study is reported at the end of the paper.     

The effect of the drum-buffer-rope (DBR) approach on the performance of a synchronous manufacturing system (SMS)

The main objective of any manufacturing system is to organize the resources in a shop floor for effective transformation of raw materials into finished products. Synchronous manufacturing (SM) is a manufacturing management philosophy that has a set of principles, procedures and techniques where every action is evaluated in terms of a common global goal of the organization (Seetharama et al., 1997, Production Planning and Inventory Control). A manufacturing system that adopts the above principle is called as synchronous manufacturing system (SMS). In order for a manufacturing plant to achieve the benefits of a synchronous operation, a logistical manufacturing (SM) is a manufacturing management philosophy that has a set of principles, procedures and techniques where every action is evaluated in terms of a common global control system that is manageable and results in predictable performance is required. The drum-buffer-rope (DBR) approach, which is a generalized system, satisfies the above requirements through computer simulation. This paper focuses on the effect of DBR principles on the performance of a synchronous manufacturing system. A case study has been taken up in a small-scale industry and analysis has been carried out on the effect of the DBR approach on the performance of the system. This work has been performed on an IBM/PC compatible system using the promodel software and C language.     

A model for an integrated manufacturing system implementation in China: a case study

This paper describes a process which a company adopted to enhance her manufacturing system in a step-by-step manner. In order to increase the competitiveness of the company, the authors have identified a number of improvement strategies which were specific to the economic and political environment in China. The center of the strategies is a vision of an integrated manufacturing strategy. The detailed design and implementation of this vision is conducted through the proposed systematic manufacturing strategic analysis. The integration process encompasses various elements such as Total Quality Management (TQM), Manufacturing Resources Planning (MRPII) and Real-Time Monitoring System (RTMS), it emphasises not only the use of appropriate modern technology but also the management of technology change. In this paper, a concept model is used to describe the integration process, the detailed implementation is also elaborated using a proposed implementation process model. By adopting the integrated manufacturing system, and through continuing improvement, the productivity and hence the profitability of the company is increased. It is anticipated that the integrated approach to the design and implementation of manufacturing systems will be an important contribution towards the manufacturing strategy in a labour intensive environment such as China.     

A simulation study of dispatch rules for reducing flow times in semiconductor wafer fabrication

Semiconductor wafer fabrication involves very complex process routing, and reducing flow times is very important. This study reports a search for better dispatch rules for achieving the goal of reducing flow times, while maintaining high machine utilization. We explored a new simulation-based dispatch rule and a queue prediction dispatch rule. Using simulation experiments and an industrial data set, we also compared several other dispatch rules commonly used in semiconductor manufacturing with our proposed dispatch rules. Among these rules, in addition to the simulation-based dispatching rule, the shortest-remaining-processing-time, earliest-due-date and leastslack rules also performed well in terms of reducing flow times. The reasons behind these good rules are discussed in this paper. Based on the previous works and this study, accurately predicting and effectively utilizing future flow times can improve the quality of production management decisions.     

Simulation-based production schedule generation

Abstract

While simulation has been used in manufacturing for many years, predominantly for facility design, it is within the last few years, that simulation languages have been developed to a point where they can be used on a day-to-day basis to generate schedules and predict their performance. This paper describes our use of different modelling techniques to develop a production schedule generation system. An example describing a system for a small- to medium-sized order producing company using SIMAN/CINEMA is included. While addressing the shortcomings of existing scheduling systems it is shown how the approach taken is a feasible way of creating a dynamic goal-driven simulation-based production scheduler. The paper does not aim to describe an ‘off the shelf’ scheduling system product, but rather to give an overview to methods, techniques and experiences which enable us rapidly to tailor a simulation-based scheduling system to the specific needs of a company.     

Simplest strategies method for manufacturing workcell restoration

We consider the production process of a manufacturing workcell. Production items obtained from an outside supplier are not processed adequately as far as their quality is concerned. Production items meeting the required quality depend on the workcell state, which degrades according to the number of produced items. The workcell is completely restored by some restoring operations leading to its as-new condition. The method of deriving the restoration period, which leads to the maximum probability that produced items meet the required quality, is introduced. It is based on the nontraditional approach, i.e. on the simplest strategies method for the formulation of the problem presented here. The implementation of this optimization approach is illustrated with an example.     

CIM implementation for job-shop environments

Abstract

Abstract. The small to medium-sized job-shop manufacturing industry can benefit most from the implementation of computer integrated manufacturing (CIM) technology, to meet the increasing demand for high-quality and economically priced products. The injection mould making industry is a typical representative for this group, where a manufacturer would generally produce moulds which consist of parts that are standard to every mould type or very similar. Thus, manufacturing techniques, such as group technology (GT), and production planning and control (information) management systems could make significant contributions in improving the efficiency of design and production operations.

The objective of the project, presented in this paper, was the development of a GT-based classification and coding (C/C) system for injection mould parts especially for the design and process planning phases, and the development of a production planning and shop-floor control (SFC) information management system.

An extensive investigation was carried out on existing GT-based C/C systems. This investigation, followed by a thorough examination of many injection mould parts for determining geometric similarities, led to the development of part families (classes) required for GT implementation. An OPITZ-type GT system was developed, thereafter, for the C/C of the manufactured parts of the target company.

The production planning and control software that has been developed for the target company utilizes a relational data base management system. It consists of 13 application programs, which provide a tool of organizing information for efficient production planning and SFC. The programs are designed to cover all manufacturing operations of a job from the proposal to the final testing stage. Shop orders and dispatch lists are created using this software for effective and prioritized SFC. Shop status and job status reports are generated based on feedback information received through time card entries.     

Development of demand pull type control methods: The design of block action production control methods to reduce throughput time and improve supply chain synchronization

In this paper the implementation of time based manufacturing strategies and pull type control systems in an organization manufacturing electrical switchgear built to customers individual requirements are discussed in detail. The concept of block control to synchronize the production time of all internally and externally sourced components and materials is also introduced in an attempt to simplify production control methods and reduce throughput time. Savings in time and cost are described during a twenty months period of restructuring. Foundations were laid for a second objective which is an attempt to gain some linkage between throughput time reduction and resultant production costs.     

Is the scheduling task context-dependent? A survey investigating the presence of constraints in different manufacturing contexts

Abstract

Most studies regarding real scheduling constraints only consider the constraints related to the specific manufacturing environment studied, limiting the possibility of drawing general conclusions. A survey of 50 companies was conducted in order to discover which constraints were present and what their relationship was with the scheduling context. This paper investigates which practical scheduling constraints are present in the manufacturing industry and whether the scheduling task is context-dependent. Results of this study show that some practical production constraints are context-dependent.     

Managing green productivity: Some strategic directions

The twentieth century has been the hallmark for managing total productivity, where the emphasis is towards maximization of outputs commensurate with the consumption of inputs. This is being challenged now to evolve the world class manufacturing strategy requiring a paradigm shift. This shift is towards green productivity, which looks forward to socially appropriate production and consumption aiming at value innovation and resource conservation. This paper is an attempt to outline the concepts and experiential learning about green productivity.     

A systematic review of research into the management of manufacturing capabilities

Abstract

Our study aims to explore the past and present knowledge related to the management of manufacturing capabilities and to assess the extent to which our knowledge of this field has developed. It places specific emphasis on the philosophical foundations of the field, while also providing a set of directions for future research. A systematic review is applied, covering 104 articles. The authors unfold a strong dominance of the positivist paradigm and call for a more balanced and informed approach in philosophical and, more specifically, methodological selection by scholars. In terms of the research content, a strong bias exists towards measuring the impact that certain manufacturing capabilities and various configurations of these may have on key performance indicators, such as cost. Our review warns on the dangers of following a dominant paradigmatic stance and on the limitations of researching a limited area of the complex and dynamic manufacturing capabilities arena.     

Experimental earliness/tardiness production planning with the due window system

In order to use the philosophy of JIT to improve the production planning method of MRP-II, we propose the experimental software system of the earliness/tardiness produc tion planning problem with due window. By means of the approaches and model reported in this paper, the optimal production planning can be achieved. The recommended model extends the problem of due window from the shop scheduling level into the aggregated planning level of mass manufacturing systems. Simulation results have demonstrated that the experimental software is a useful tool for the production management of repetitive manufacturing enterprises.     

Period batch control: Classic,not outdated

Period Batch Control was developed and first applied during the Second World War. The historic roots are discussed and the principles of this classic production planning approach explained, PBC compared to other production control concepts, and it is demonstrated that it may still be fruitfully applied, especially in combination with cellular manufacturing. It is therefore considered as a classic, but not outdated production planning concept.