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SUMMARY The London School of Economics have, since 1959, studied the jobs of supervisors in a number of plants to demonstrate their range and variety and the relation of supervisory systems to technology. A previous article (see below) on the first part of the research argued that there was no straightforward relationship between the two, but that organizational and human factors could also greatly determine supervisory jobs. This paper describes the last part of the research which was devoted to a far deeper and more detailed analysis of supervisory jobs in one large firm in an attempt to find more concrete evidence of different influences on supervisory jobs. The results show that the nature of the product, the technical situation, the factory organization, the supervisory training programme and the supervisor's personality all affected both his behaviour and the demands made on him. A supervisor was seen to be reacting to a continuous succession of pressures, some of which ran counter to others. The re...

This paper treats work variety as a subjective variable rather than an objective attribute of work. The results of several industrial experiments are outlined in presenting a method for measuring perceived variety in terms of a psycho-physical function. A null finding is reported concerning the relationship between variety and work performance.

Continuous production processes characteristically do not result in production units which are well-defined from a quality control standpoint. Application of standard statistical quality control techniques requires sampling one litre, ounce or yard of product while the product is produced by the barrel, ton, or reel. Thus, direct application of quality control techniques is difficult. The possibilities offered by the use of exponential smoothing are analysed in this paper. Use of this method permits determination of meaningful control charts with a minimum of effort. The method is illustrated by applying it in the study of water pollution control.

SUMMARY Acceptance sampling plans are designed under the assumption of perfect inspection. However, inspection tasks are not, even under ideal inspection conditions, free of error. In this paper we consider the effects of inspection error on probability of acceptance, average outgoing quality, and average total inspection. These measures are examined under both replacement and non -replacement assumptions. Also, a method is presented whereby an acceptance sampling plan may be designed which explicitly considers inspection error.

SUMMARY This paper presents some case studies of quality control practices based on the authors’ visits to some manufacturing industries. The statistical methods applied in each quality control programme are emphasized.

To be successful in mechanized assembly, one has to realize that it is an attempt to replace, by a mechanical device, the skill and judgement of a human assembler. Although a low value of operator involvement can be achieved, complete non-involvement is not economically viable. This is owing to the high cost of sophisticated devices necessary to take complete account of the faults which can occur due to random combinations of system accuracy and component quality. This paper is concerned with: (a) positioning accuracy of the system used: (6) the dimensional quality of the components to be handled; and (c) the effect of interaction between simple magazines and the component inaccuracies as in (b) and the way the component is gripped and transported by the system.

This paper presents a system of using a cause and effect diagram (also called the ‘fish bone ’) with the addition of cards, developed and applied in our company. This participative system worked remarkably well in the field of quality control. The philosophy behind the system is introduced in this paper, and a scientific analysis is made of the factors needed for success.

Most of the decisions in production management require simultaneous study of interdependent subsystems. In this paper we propose a compatibility matrix which can be used as a possible aid for integrating production decisions. The compatibility matrix generates decision alternatives for a production system, given the decision alternatives for its subsystems and compatibility relationships between each alternative of a subsystem and all the alternatives of the remaining subsystems. The mutually-exclusive decision alternatives provide the manager with a wide range to choose from. These alternatives can be used as inputs to mathematical simulation models. For ill-structured problems the compatibility matrix offers a viable tool in achieving synergy

It has now been generally established that the output rate of balanced production lines having variable operation times can be improved by deliberately unbalancing the line through assigning proportionately lower operation times to the middle station(s). Nevertheless, a production line may be balanced in terms of mean operation times at the respective stations yet unbalanced in the sense that the interstage buffer capacity allocation or the operation time variability are not equal for all stations. This paper attempts to study the effect that the latter types of imbalance have on the output rate and average number of work units in the system for some production line situations. Computer simulation experimentation results confirm that inequality of variability of operation times have the same general effect on output rate as inequality of operation times but little effect on the number of units in the system. Inequality of interstage buffers, on the other hand, affects the average number of units in the sy...

In the quality control system, most of the information for decision making and problem solving can be obtained by inspection activities. Therefore, the inspection work should be organized to maximize meeting the quality objectives. It has already been publicized that data obtained from measurement of inspection performance will supply an effective basis for assessment and design of the inspection station and inspection job. This paper is intended to report on a case study of measurement of inspection performance conducted for the assessment and design of an inspection job in a manufacturing company. Quality control specialists selected three groups of items having representative deficiencies under routine inspection, inspected as inspection job samples. They had individual inspectors inspect each sample to obtain data consisting of the rate of defects detected out of all the defects, and the proportion of erroneous findings in the total number of findings by each inspector. Thus they identified many probl...

This paper reports development activities for a new production management system aiming to obtain excellent product quality and high productivity by heightening the morale of the workers and by harmonizing the workers' human needs with the company's organizational needs In the course of proceeding with the development of the new production management system, first, the needs of workers as a whole and as individuals were analysed by the multivariate analysis method, so as to clarify the differences in their motivations in regards of the workers' attributes, working environments and the management systems Secondly, several proposals for improvement were presented to workers as a whole and as individuals and such proposed improvements were experimentally implemented one after another in order to harmonize the human needs with the organizational needs.

This paper presents the results of a detailed study of the practice and management of quality control in the chemical manufacturing industry. A questionnaire survey formed the first part of the investigation, which reveals that this sector of industry makes surprisingly low use of statistical quality control techniques. Information on the organization and operation of QC suggests that the industry has well documented analysis procedures and collects large volumes of data. It is pointed out, however, that statistically valid interpretation and use of this material, particularly in process control, is not prevalent.

Research is yet to be clone on the direct economy of the electro-discharge machining process which is a vital criterion for the users of the machine. In this paper an expression for contribution rate, as a function of process variables, which is a direct indicator to measure the economic objectives of the process for a production system is derived and a methodology forestimating the process and hence the objective function with respect to the process variables is cited. Further, in this paper a Complementary Geometric Programming algorithm is used to optimize the contribution rate under technical and technological constraints. This paper also compares the contribution rates obtained from the results of the optimization problem with the following objective functions under compatible sets of restrictions: (i) Contribution rate. (ii) Material removal rate. (iii) Electrode wear rate. (iv) Ratio of material removal rate to electrode wear rate. The data, for this paper is generated from JUSPA III, the ...

The paper defines batch or job shop production and reviews the functions of production planning and production control in a job shop manufacturing situation. It argues that the separation of planning and control has resulted in the artificial isolation of the sequencing problem in job shop research. It attempts to redefine the production control function for a job shop, now called job shop control, and discuss the activities it involves. The major decision-making problems associated with job shop control are highlighted and an objective function of costs to aid in management decision making is evolved.

This paper explains an approach to establishing the total reliability of cutting tools on feeding automatic machine lines as a function of time, and based on this the establishment of cutting-tool costs and total machining costs as a function of cutting-tool reliability. Based on observations, made over a long period, cutting-tool reliability is established for certain operations (Weibull distribution), and the total reliability for the whole line established as the product of the individual operations. Cutting-tool costs are shown as the sum of tool replacement, sharpening and depreciation costs, and total machining costs as the sum of machining values, machine tools and cutting tools. By variation of the cutting-tool replacement time, the tabular change dependencies are obtained as a function of cutting-tool replacement time. By elimination of replacement time from the above dependencies, the cutting-tool cost changes and machining costs are obtained as a function of the cutting-tool reliabilit...

Analyses (Boothroyd and Redford 1968) have indicated that a knowledge of the relationship between parts quality and cost is essential if the performance of a mechanized assembly machine is to be optimized. For mass-production parts, improvements in parts quality are invariably obtained by some form of inspection and a knowledge of the cost of and efficiency of inspection is therefore desirable. Experiments have been carried out for visual inspection to determine the effect on inspection rate and efficiency of changing the quality of the part being inspected and the number, position and type of features of the part which can be inspected. The results of this work are presented in this paper and their significance is discussed.

Time structure of a job is affected by the length and frequency of its constituting tasks. It is probably one of the major variables in the subjective perception of variety of jobs. This paper defines an index called Non-Repetitive Cycle Time (NRCT) which can be used as an indicator of the temporal pattern of the job. Investigation of the value of NRCT for jobs in two organizations confirmed the hypothesis that NRCT is positively correlated with the job level in the organizational hierarchy. This index can be used by job designers in estimating the temporal impact of assigning tasks to jobs

In examining the basic requirements of warehouse layouts, Berry (1968) called for the use of a simulation model for evaluation purposes. Marsh (1979) provided such a model. This paper summarizes a computational experiment which compares layouts using the Berry and Marsh approaches. In the absence of specific information about a particular warehouse, it is necessary to provide ‘appropriate’ levels for the independent variables. Statistical analysis is used to determine whether significant differences exist between the two layouts. Based on the stated criteria there are no significant differences between the two layouts except for size. Under these conditions the Marsh approach dominates when measured by primary storage area and by lineal aisle frontage

The paper deals with the problem of optimization of a quality inspection process structure. The problem is identified with designing an optimal arrangement of inspection operations in a production process (linkages of the quality inspection process with manufacturing and accessory processes). Three mathematical models for the cases of specialized and versatile inspection stations are formulated. It is shown that the problem can be treated as a particular case of a standard assignment problem. An optimization procedure, grounded on Balas' algorithm, is proposed. A numerical example, based on real data, is given.

The work described in this paper is part of a large investigation of the usage of statistical methods of quality control (SQC) in British manufacturing industry. The introduction provides a review of previous work, which revealed that industry in the UK makes surprisingly little use of SQC techniques. These results were so striking that a further investigation was initiated to discover: (i) the ‘barriers to acceptance’ of SQC (ii) a methodology for its successful implementation This paper describes the first phase of this work, which was aimed at discovering the reasons for the low usage of SQC. In summary, the major barrier preventing companies from introducing SQC is lack of knowledge. Whilst this was often not the first reason given, much circumstantial evidence from questionnaires and direct evidence from interviews suggests that decisions are often taken on the basis of very little or no knowledge. Clearly, there is an urgent need to increase awareness and knowledge of SQC.

We refer to the process of uncovering the causes of failure in service of a manufactured item as ‘industrial diagnostic’. Based on our experience with such a problem over the past two years, we concluded that traditional approaches are inadequate, while the more modern approaches of ‘system failure diagnosis’ are tailored more towards the detection of failure in a complex piece of equipment than towards the detection of failure over the ‘life cycle’ of a product. In this paper we briefly review the traditional as well as the more modern theories of diagnosis, and expound on our approach to the problem. This approach contained both ‘field’ as well as ‘production plant’ research. The objective of the former was to determine the influence of the various factors on product degradation in service; while the objective of the latter was to determine the ‘significant plant parameters’ and to construct the ‘quality function’ (QF) of the producing plant. It is our contention that industrial diagnostics has...

The purpose of this paper is to determine the cost effectiveness of recently proposed single-stage lot-sizing algorithms in multi-stage settings. Seven different algorithms and six comhinations of methods were examined in conjunction with four cost modification procedures. These procedures attempt to account for the interdependencies across stages by altering the costs employed for decision-making purposes. A series of simulation experiments was conducted where the set-up cost, the product structure, and the demand distribution were varied. It is concluded that the combination methods when used with some of the cost modifications result in enhanced performance in comparison to other sequential approaches.

This paper analyses the cost-quality implications of process improvement versus inspection enhancement for n-stage serial production processes. The analysis determines, For a given environment, the combination of process and inspection performance that minimizes the cost of each defect-Free unit produced. Insight into the process-improvement inspection-enhancement trade-off, is obtained by identifying a base-line environment and then varying key environmental parameters including: measures of production and inspection quality, functional relationships between these qualities and their costs, and penalty costs incurred by delivery of defective units to the customer. The results of the analysis are presented in the context of decisions or strategies for the immediate, short-run and long-run optimal combinations of process improvement and inspection enhancement.

SUMMARY The use of fuzzy methodologies is an efficient way of accounting for vagueness in human judgment. This paper illustrates potential applications of fuzzy methodologies to various areas of production management including new product development, facilities planning, human production management, production scheduling and inventory control, quality and industrial process control, and cost/benefit analysis. In addition, important areas for new research are discussed.

SUMMARY Productivity increases attributed to the Japanese management approach known as just-in-time (JIT) include better customer service, higher quality levels, increased labour and machine efficiency and reduced inventory levels. These potential benefits, as well as others, have caused many large companies to examine JIT. Most of this interest has been focused on JIT applications for large repetitive manufacturers. Research, and the experiences of some managers, indicate its potential in job-shop and process industry environments. Little research has been conducted in small manufacturing environments This paper examines JIT, its elements, benefits and feasibility in a small manufacturing setting. A bottling company is described and examined in terms of its suitability for JIT implementation. This example shows that not all elements of JIT are feasible for all situations. Each element of a JIT system should be examined as it applies to small or large manufacturing or to repetitive, job-shop or process in...

SUMMARY This paper considers the factors affecting the design of material-requirements-planning (MRP) systems for make-to-order companies. It shows how key elements of MRP, such as bills of material, design change control, master production scheduling (MPS) and order entry, can be made to function effectively within this type of business environment. The work is based on a major research programme between Simon Container Machinery Ltd and the UMIST, Total Technology Scheme. †Science and Engineering Research Council grant awarded under the Total Technology Industry/University Programme.

This paper defines the potential contribution of quality assurance activities in the context of companies' economic needs, which were derived through managers' opinions regarding possible ways for increasing the operating profit of their companies. From it emerges a desired expansion of the traditional quality tasks towards an integrative economically oriented system. This idealized approach, providing an economic link between the quality of design and the quality of conformance is illustrated by many Japanese industries. The data was based on the sample of Israeli electric and electronic industries described in Part 1.

The purpose of this paper is to integrate a quality control (inspection) procedure into a job shop manufacturing process described by an M/M/1 queue. Given a joint inspection and queueing system, an optimization problem for minimizing inspection and queueing related costs is formulated and resolved.

Absenteeism is one of the major problems of Indian industries. It necessitates the employment of more manpower than the jobs require, resulting in the increase of manpower costs, and lowers the efficiency of plant operation through lowered performance and higher rejects. It also causes machine idleness, if extra manpower is not hired, resulting in disrupted work schedules and assignments. Several studies have investigated the causes of absenteeism (Vaid 1967) for example and their remedy and relationship between absenteeism and turnover with a suggested model for diagnosis and treatment (Hawk 1976) However, the production foremen and supervisor will face the operating task of determining how many extra operatives are to be hired in order to stave off the adverse effects of absenteeism on the man-machine system. This paper deals with a class of reserve manpower models based on the reject allowance model familiar in quality control literature. The present study considers, in addition to absenteeism, machine failures and the graded nature of manpower met within production systems and seeks to find optimal reserve manpower through computer simulation.

The purpose of this paper is to define conceptually and operationally, a measure of quality density in manufacturing. This is expressed in terms of a manufacturing process propensity to ‘output’ units which are defectives, as a function of the manufactured production output, the manufacturing deterioration process, maintenance, quality control, and generally the risks a manufacturing process is subjugated to. Particularly, we assume that the production process induces ‘shocks’ which lead to poorer manufactured quality, while maintenance efforts are continually being employed to restore the process propensity to produce units of better quality. Quality control is used then to monitor the output quality of units produced. Using a methodology of level crossing in stochastic point processes, the stationary probability distribution of a manufactured output quality is defined. Applications to production quality management, combined quality and maintenance management, as well as quality control are considered. F...

In a complete inspection plan, all outgoing items are subject to inspection, and the items failing to conform to the predetermined specifications are reworked so that their quality characteristics are exactly equal to the expected value (target value). This paper presents an economic model to determine the most profitable specifications for the complete inspection plan with the considerations of (a) economic loss caused by quality deviations, (b) rework cost, and (c) inspection cost. The solution to the cases in which the inspection cost is a constant provides important insights of the model. A detailed solution procedure is also given to a model in which the inspection cost is a linear function of the width of the specifications, the quality characteristic is normally distributed, and other loss and cost functions are assumed of a quadratic or linear form.

The existing models for machine requirements planning are based on the assumption of a constant production rate per machine throughout the planning horizon. This assumption is not valid in many production environments where the manufacturing productivity increases because of factors like: product and process redesign, more efficient maintenance and setup procedures, direct-labour learning, reduction of scrap losses, etc. The objective of this paper is to present the effects of improving manufacturing productivity on machine requirements planning, In addition, an integrated model which combines the aggregate production planning and machine requirements planning problems is discussed under the effects of manufacturing progress function.

This paper provides a set of recursive equations for computing the AOQ (average outgoing quality) of an unreliable random FMS (flexible manufacturing system). The FMS is described using Whitt's approximation to a network of GI/G/S queues. Relationships between the operating and quality manufacturing characteristics of the FMS are found. Numerical examples are provided and the impact of outgoing quality variability on location of inspection in an FMS is discussed. This latter topic is left for further research however.

Tests of product quality that depend exclusively on one or more of the five senses of a human inspector are known as sensory tests. Since the ability to make correct sensory judgments can vary substantially from person to person, it is important in the selection and training of inspectors to be able to distinguish between inspectors of differing sensory abilities. This paper proposes a new approach based on the Kullback-Leibler data for classifying inspectors by panel tests. A method of deciding the same size in the test inspection lot with given risks is also suggested. The recommended procedure is simple, practical and relatively effective.

Competitive pressures continually force management to examine cost and quality levels of production systems. In this paper these issues are addressed via a model that synthesizes several potential features of production systems: production processes, quality control procedures, in-process inventory and reprocessing. For any specified inspection configuration the model can be used, for serial production systems, to obtain closed-form expressions for two important decision variables: optimal lot size and reprocessing batch size, which minimize the total system costs. A numerical example highlights the interdependencies and the role of various system features in determining the values of the decision variables and hence in reducing the total costs. The paper also discusses the managerial implications of the model.

In this paper, the effectiveness of some approaches to on-line supervision of the grinding process is discussed. The advantages and corresponding shortcomings of some indirect methods previously recommended are compared. The authors recommend the information distance measure as a new criterion for distinguishing the different stages of the grinding process. Experiments have verified the advantages of this criterion in the terms of its efficiency, reliability, adaptability, computer storage saving and simplicity of instrumentation

While carrying out a study of the collection and use of quality-related costs in manufacturing industry the authors found in the literature many notional models purporting to indicate the relationships between the major categories of quality costs and a few sets of real data. Despite being based on common principles, there are wide differences between some of the models and between the models and real data. The paper categorizes and discusses the models in the light of the research experience. It is concluded that many of the models are inaccurate and misleading and serious doubts are cast on the concept of an optimum quality level corresponding to a minimum point on the total quality-cost curve.

SUMMARY This paper examines the order review/release (ORR) function and its impact on the operation of the shop floor. A source of disagreement between practitioners and researchers, ORR is an important element of any shop floor control system. This paper attempts to provide a better understanding of this element by presenting a framework for ORR. This framework not only identifies the important dimensions of ORR but also new dimensions for research. The paper also explores the relationship between ORR and job dispatching through a simple computer simulation model. The results indicate that the ORR, while reducing time spent in queue on the shop floor, does not always reduce the total time spent in the system.

Just-In-Time (JIT) research has been limited primarily to descriptive works, case studies, surveys, and a few simulations and analytic models. This paper, by contrast, reports on an empirical field study exploring the relative importance of several JIT-based independent variables to the total level of supplier-linked inventory in an environment where the customer was implementing JIT. The results lend some support (as expected) to classical inventory theory, but also indicate the relative importance of the variables in this JIT environment. Open-ended discussions with customer and supplier managers lend further insights into the results.

SUMMARY This paper presents an analytical method for configuring the network of a fixed-path, closed-loop material handling system. The method is applicable to towlines, automated monorail systems (AMS), automated guided vehicles systems (AGVS), and other equipment types. The purpose is to make good initial decisions with respect to adding shortcuts (cutbacks), adding off-line spurs, and their length, so that of the thousands or millions of possible network configurations only a very small number need subsequently to be examined by simulation. The approach taken is to develop volume-delay curves for load-carriers passing a load/unload station, based on average transport requirements. Using this information we develop, as a function of the number of carriers moving past a station, cost curves that include carrier costs and spur costs, for the two possible situations at each station: build or don't build a spur. A mainline blocking tolerance is used to determine the spur capacity for the build situation. Af...

SUMMARY This is the second in a two-part report on control engineering considerations in quality assurance. The first paper introduced some basic concepts in the measurement of the ‘loss’ due to poor product quality, and approached the issue of parameter optimization of the control system through the modem of manipulating the PID constants, using an experimental approach coupled with simulation as the methodology to achieve the desired objective. This paper approaches the problem of parameter optimization via mathematical programming, and then addresses the issue of setting the standard of system performance through Markov decision processes.

SUMMARY Traditional feature extraction vision techniques are well proven. However, in certain circumstances they suffer from some severe disadvantages such as processing time, image complexity, internal features and lighting levels. This paper describes the use of a hybrid system using artificial intelligence techniques in combination with traditional feature extraction techniques which overcome some disadvantages. This hybrid system is able to locate and orientate parts with complex internal features and to provide an indication of quality.

SUMMARY High volume, highly automated, information intensive, short cycle manufacturing systems severely tax most conventional statistical process control techniques. To meet this new manufacturing domain's control requirements, a new approach is needed. This paper presents such a process control procedure, sufficient statistics process control (SSPC). By drawing on empirical Bayes techniques, SSPC models the time sequence of the process while simultaneously reducing to a few sufficient statistics the large volume of incoming data. As a result, it provides real time, on-line quality control. The paper discusses the conceptual and mathematical foundations for SSPC. Its operation is illustrated through an example. Finally, the paper concludes with a discussion of the limitations of SSPC.

SUMMARY This paper interrelates and synthesizes the economic design of quality and process control policy and the management of a production system described in terms of an M/G/X queue. A mathematical model is developed to determine the optimal quality and process control policy when both the quality and quantity issues in the production system are considered. The optimal control policy is defined as the one that maximizes the expected profit per unit time over an infinite horizon. Hypothetical data is used to illustrate the impact of on-line control policies on the operating characteristics of the production process. For a given control policy, it is shown that the expected profit per unit time of the production system can be increased by either improving the reliability of the production system, increasing the arrival rate of incoming jobs, increasing the system's processing rate, or shortening the system's shutdown time. The results also indicate that the larger the performance difference between the i...

SUMMARY This paper discusses the results obtained from a micro-computer program SIMTUP developed at the National University of Singapore for off-line adaptive optimization of a multi-pass CNC lathe-turning process. An initial estimation based on empirical models is conducted to obtain the total amount of time, cost and resources required for production. These models are to be updated with a view to arriving at new optimal cutting conditions with respect to production time. The optimal cutting conditions are based on the minimum production cost change with respect to production time for a dynamic system, a principle taken into account in SIMTUP. Estimations can be conducted at any stage to re-evaluate the total resources required. The results obtained can be used as effective productivity improvement tools for project management and quality control.

SUMMARY This paper presents an accelerated approach and an automated system for short-term machinability evaluation of metal materials. The proposed approach is developed for ranking materials in terms of machinability. It considers both objective factors, such as machine variables and process outputs, and subjective factors, such as the decision maker's preferences regarding different criteria (objectives, e.g. operation cost, production rate, and product quality). A set of analytical and empirical formulas relevant to different aspects of machinability are identified. A definition of machinability as a function of process outputs is proposed. A method for assessing the weights of importance of different criteria is proposed. Based on the approach, a computer software package called MACPRO for machinability assessment is developed. The computerized machinability evaluation system interfacing with sensors is configured to facilitate data sampling/processing and man/machine interactions. Results of experim...

SUMMARY This paper presents a comparison of the manufacturing planning and control practices between firms in South Korea and Europe in the non-fashion textile and small machine tool industries. The key differences in practice were found in the details of forecasting and production planning, the market influence on shop-floor activities, the organizational level used in planning and control, and the level of sophistication in terms of computers and techniques used. The implications of these findings are important for firms with plans to enter into joint ventures or other cooperative arrangements. The data used in this study are from a large data base of actual manufacturing practices collected from countries around the world.

The short-term production planning function for setting up a flexible manufacturing system (FMS) prior to production should be developed so as to interact well with the operation of the system over time. During FMS operation, planning for system set-up has to be performed somewhat periodically, for example, when the part mix is changed, or when the production requirements are finished for some part types, or when a machine breaks down. Since all cutting tools required for all part types that need to be machined cannot usually fit in the machines' limited capacity tool magazines, decisions need to be made concerning which part types will be produced next. This paper suggests a more flexible approach than is typical for short-term production planning. The differences between the proposed flexible approach and previous approaches taken in the literature and in industry to solve these problems are provided. A description of when either a batching or a flexible approach is appropriate is provided. An existing ...

As manufacturers continue to automate their factories, they discover that existing cost measures should be updated. Much of the existing literature has discussed the ‘why's’ but there is little about the ‘how's’. This paper expands the cost concept to include quality and flexibility because they are critical factors for performance evaluation and project justification of advanced manufacturing systems. Then, a quantitative method of estimating the cost elements is illustrated. Finally, various approaches to collecting parametric values of the cost model and applications of the cost model are presented.

A manufacturing cycle includes all activities from order processing to shipping. The benefits of reducing cycle time includes increased productivity and added competitive advantage. This paper proposes a new approach to the control of cycle time variability in the short-term and the reduction of cycle time in the long-term. It has been said that when the control and stability of a variable is a matter of interest, as in the case of cycle time, control charts similar to those used for controlling product quality can be used as long as the challenge of developing appropriate tolerance limits for the variable can be overcome. We make use of three propositions to implement this rationale. The challenge to establishing tolerance limits to cycle time is overcome by the use of desired worst-case cycle time. Step-by-step application of the principles of statistical cycle time control at A. B. Chance Company is used to illustrate the practical viability of this new procedure. The principles of this study may be ex...