Danny J. Johnson

Cellular manufacturing at 46 user plants: Implementation experiences and performance improvements

Despite the increasing popularity of cellular manufacturing, by now a firmly entrenched approach to factory work organization, the number of large-scale systematic studies aimed at investigating issues surrounding implementation is still relatively sparse. This paper reports on a survey study of plants involved with cellular manufacturing. A target population of high-probability users received mail questionnaires designed to collect responses related to characteristics of industry cells and the firms that have implemented them (a companion paper, based on the same survey data, describes procedures and issues in cell design). Forty-six plants supplied detailed data on 126 of their cells, including reasons for establishing them, types of operations performed in the cells, problems faced and lessons learned during implementation, and achieved performance improvements. This study provides confirming evidence that manufacturing cells, which may house a large variety and many combinations of processes, can prov...

Supplier Risk Assessment and Monitoring for the Automotive Industry

Purpose – This research aims to develop a supplier risk assessment methodology for measuring, tracking, and analyzing supplier and part specific risk over time for an automotive manufacturer.Design/methodology/approach – Supply chain risk literature is analyzed and used in conjunction with interviews from the automotive manufacturer to identify risks in the supply base. These risks are incorporated into the development of a temporal risk assessment and monitoring system.Findings – A framework of risk factors important to the auto manufacturer is presented. A multi‐criteria scoring procedure is developed to calculate part and supplier risk indices. These indices are used in the development of a risk assessment and monitoring system that allows the indices to be tracked over time to identify trends towards higher risk levels.Research limitations/implications – There are a number of operational issues identified in the paper that could be investigated in future research. One such issue is the development of ...

EMPIRICAL FINDINGS IN MANUFACTURING CELL DESIGN

Cell design is the most researched topic in the area of cellular manufacturing. The preponderance of studies has focused on the development of models to assist with cell formation, i.e. the initial stage in the cell design process where the parts and equipment are determined. On the other hand, fairly little is known about the broader context in which cell design takes place, and the processes that users follow. The purpose of this study was to learn more about the methods, goals, considerations, and constraints that industrial users apply to cell formation and cell layout, as well as the actual outcomes of those processes (such as cell configurations and staffing patterns). This paper adds to the sparse literature on empirical cell design by reporting on findings derived from a survey study of cell users predominantly drawn from the metalworking industry (related data have previously been published in Wemmerlov and Johnson (1997)). Supporting evidence is primarily taken from survey and field studies by Wemmerlov and Hyer (1989), Harvey (1993), Choi (1996), Suri et al. (1996), Olorunniwo and Udo (1996), Marsh et al. (1998), Johnson (1998), and Hyer and Brown (1999). The findings should be of interest to both students and practitioners of cellular manufacturing, and could serve as guidance for researchers seeking to develop more effective methodologies for solving the cell design problem for industrial users.

Research issues on factors influencing the choice of kitting versus line stocking

Kitting and line stocking systems are common alternatives for component storage in assembly environments. Despite the need for knowledge about when and where each system would be applicable in industry, research on the choice of kitting versus line stocking systems in industry is quite sparse. This paper identifies a number of research issues that might influence this system choice decision based on an analysis of the kitting operations and the potential move to line stocking at an electronics assembly company. Research questions are presented in the areas of product characteristics (volume, variety, and size), storage and material handling, production control, performance impact, and implementation. The issues identified here highlight factors that might influence the choice between kitting and line stocking, and present a rich array of research opportunities in a number of relevant areas.

A framework for reducing manufacturing throughput time

Manufacturing throughput time reduction can be a daunting task due to the many factors that influence it and their complex interactions. However, there are basic principles that, if applied correctly, can be used to reduce manufacturing throughput time. This paper presents a conceptual framework that illustrates these principles. The framework illustrates the factors that influence manufacturing throughput time, the actions that can be taken to alter each factor, and their interactions. The framework is detailed enough to provide guidance to the industry practitioner on how to reduce manufacturing throughput time, while being general enough to apply to most manufacturing situations.

A spreadsheet method for calculating work completion time probability distributions of paced or linked assembly lines

This study presents a spreadsheet method for computing the work completion time probability distribution of a linked assembly line with variable station service times. Once developed, this distribution can be used to analyse the probability of completing all work at all stations within a given cycle time on either a linked or mechanically paced assembly line. The method can be used to determine what cycle time to set on a paced line, given a desired workload at each station. Alternately, given a desired cycle time and probability that all work has been completed at each station within the cycle time, the method can be used to determine how much work to allocate to each station on the paced line. The method is simple, easy to use, and works with any continuous or discrete station service time distribution that can be specified in a spreadsheet. Comparisons between the output of the spreadsheet method and simulations of the same system indicate the spreadsheet method is quite accurate. Hence, the method can be useful to both researchers and practitioners working with the design and/or behaviour of linked or paced lines, and it provides an easy-to-use teaching tool for illustrating characteristics of linked or paced assembly lines.