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This paper addresses the application and comparison of spreadsheet analysis (LOTUS 123), rapid modelling (MANUPLAN II), and simulation (STARCELL) for the design and evaluation of manufacturing systems. The objective is to evaluate the quantity and quality of the required inputs, generated outputs, and the amount of time required for each of these analytical tools compared to the amount of knowledge gained. A comparison is conducted for an application to an automatic insertion card production facility where the best machine/cell configuration was emphasized to simplify the system and increase its efficiency. Results of this evaluation provide insights into the efforts and value obtained from using increasingly more detailed modelling procedures. [ABSTRACT FROM AUTHOR]

A model is presented for calculating the starting and finishing times of jobs processed in a group technology (GT)-structured flow line workcell in light of transient and steady state conditions. The GT-based workcell is becoming an important component of a just-in-time (JIT) strategy to gain increased productivity and proper response to customers in small-to-medium lot size manufacturing operations. Considering the four factors of machines in series, finite buffers between machines, piece-by-piece continuous flow processing, and setup times treated separately from processing times, the model provides critical information in implementing JIT such as job starting and finishing times as well as the makespan for processing a set of jobs. The recursive procedure of the model is presented in a step-by-step fashion, and illustrated through a numerical example. Furthermore, the performance of the model is evaluated through a set of industrial data by comparing results obtained from a deterministic simulation model. [ABSTRACT FROM AUTHOR]

The initial stage in the facilities design of cellular manufacturing systems involves the identification of part families and machine groups and forming cells possessing specific manufacturing capabilities. A new heuristic for the part family/machine group formation (PF/MGF) problem is presented in this paper. The distinguishing feature of this heuristic is its consideration of several practical criteria such as within-cell machine utilization, work load fractions, maximum number of machines that are assigned to a cell, and the percentage of operations of parts completed within a single cell. Computational results, based on several examples from the literature, show that this heuristic performs well with respect to more than one criteria. The heuristic also clarifies the source of various arguments in the literature concerning the 'goodness' of the solutions obtained by other researchers. An application of the heuristic to a large sample of industrial data involving 45 workcentres composed of 64 machines, and 305 parts is given, and the usefulness of the heuristic for trading-off several objectives is illustrated. [ABSTRACT FROM AUTHOR]

The role of process planning in small-batch, discrete parts metal working industries and the impact of the computer in automating this important but tedious job are discussed. The nature, advantages, and limitations of the manual, variant, and generative approaches to process planning are presented along with a review of the progress to date for each approach. A major thrust of the paper is to discuss approaches and strategies for structuring manufacturing methods and data in decision logic formats applicable for developing generative type automated planning systems. Although no particular approach is promoted, the paper provides an overview and information useful for approaching the task of designing a generative type system. Some detailed discussion on part coding schemes and structuring decision logic for generative type planning systems is also presented. The paper concludes with a brief discussion of the future of computer-aided process planning and the role that micro-computers will play in that future. [ABSTRACT FROM AUTHOR]

In this paper, the applications of computer simulation and statically designed experiments are presented as a means to diagnostically evaluated and design more efficient layouts for manufacturing job-shops. The simulation model is defined and driven based entirely on actual operating data, shop procedures, and the physical configuration of the shop. Utilizing the flexibility and realism of a stimulation model, layout analysis is conducted to evaluate the effects of changes in material handling methods, in-process storage locations, and various operating procedures on shop floor congestion and job throughput. An experimental design is used to allow statistical comparison of the results in the light of the variability of the entire shop system, and a predictive model for mean job flow time is developed using multiple regression analysis. The results show that an improved layout and better operating procedures can eliminate the need for additional capital investment and work force expenses, yet still provide improvements in the overall productivity of the shop. [ABSTRACT FROM AUTHOR]

The use of time series analysis to characterize the behaviour of machine centre queues of in-process inventory stored within an automated high-rise warehousing system is discussed. By treating queue behaviour as a first-order continuous process, a time constant value is obtained which indicates imbalance in the shop. This value provides a basis for interpretation and control by shop floor managers without direct observation of the queues of in-process materials. Actual time series data of in-process inventory are modelled and interpreted using this approach. Practical aspects of data sampling and parameter estimation are also considered. [ABSTRACT FROM AUTHOR]

Two equations have been obtained using regression analysis techniques which can be applied to determine storage space requirements with acceptable accuracy and minimum effort. By defining all items by means of a common parameter--packing factor--it was possible to ignore the individual weights of each item, yet still load the transport and storage unit to some practical load limits. The method used in this paper is general and can be applied to similar problems with different boundary conditions. [ABSTRACT FROM AUTHOR]

An innovative approach based on multiattribute utility theory and group processes was used to directly monitor and control cosmetic characteristics affecting product appearance to improve the quality of a product. The main advantage of this approach is its ability to provide a direct and reliable measure of visual appearance for products for which this is the critical quality characteristic. The paper is divided into two main parts. The first part briefly presents a systematic approach to develop an empirical indicator of product appearance, called the index of visual condition (IOVC). The second part presents a study of the applicability of the IOVC during process control to directly monitor and improve product appearance. This study was performed during industrial production of a ceramic product for a period of seven months. Several Shewhart charts were developed, including the first exploratory X-bar and R charts for product appearance (IOVC charts) and c-charts for number of defects. The performance of these charts was evaluated by their ability to detect special causes of variation and improve the product. The case study indicates that these two approaches complement each other. While the c-chart allows one to monitor the number of defects that impair product functionality, the IOVC chart brings a new level of capability, providing the ability to directly monitor product appearance considering defects that do not affect functionality. Both approaches were useful for process control and improvement. [ABSTRACT FROM AUTHOR]