Gregory V. Frazier

An Evaluation of Group Scheduling Heuristics in a Flow-Line Manufacturing Cell

Abstract. When a company adopts cellular manufacturing and creates a ce ll,

one operational problem that must be addressed is how to schedule parts within

the cell. Many studies have investigated scheduling rules in a cellular

manufacturing environment. However, there has been little consensus on the

best sc heduling rule to use. To address this lack of consensus, this study

evaluated the best scheduling rules from most of these studies in a flow-line

cell. The impact of two environmental factors, setup to runtime ratio and

number of part families, was also investigated. Out of the five best

scheduling rules found, three of these had not been investigated in previous

group scheduling studies. The scheduling rule that most often performed best

was selecting the part family with the most waiting jobs and sequencing these

jobs in shortest processing time order, a relatively simple rule. The more

complex rules generally showed poorer performance.

Is the Full Potential of Cellular Manufacturing Being Achieved?

Abstract. Why have results of Cellular Manufacturing (CM) implementations

been so diverse? Why after three decades do the conditions for the economic

viability of Group Technology remain unresolved? The authors interpret the above as evidence that present Cellular Manufacturing concepts and methodology are faulty due to the following:

1. The vast majority of cell formation techniques are suboptimizing CM

designs by ignoring the primary objective of CM, setup reduction, or confounding this objective with other objectives.

2. No present methods of cell formation and few scheduling techniques

consider sequential dependencies of setups and instead make general assumptions

that are in many situations invalid. The purposes of this article are to

focus attention on the primary objective of CM, offer reasons why present CM

design methods fail to consistently attain the acclaimed benefits of CM, and

offer tenets for successful CM designs.

Seed Selection Procedures for Cell Formation Heuristics

Abstract. The choice of seed machines can have a great impact on the final

solution of cell formation heuristi cs. In this study, several seed selection

rules were compared using the ODCC heuristic. An alternative cell formation

approach using the ODCC heuristic was formalized and is described.

Computational results show that this ëBRSí approach can often yield optimal


A Procedure for Dealing with Multiple Objectives in Cell Formation Decisions

Abstract. A procedure for dealing with multiple objectives in cell formation

decisions is proposed. Theoretical foundations from multiobjective decision

making have been utilized to provide a framework for the study. The purpose

of the study is to develop a procedure that provides managers with a means of

developing multiple objective cell formation decisions as an alternative to

intractable integer programming models. We use a best of random seeds

heuristic to generate a large number of alternatives. Nondominated solution

theory is used to develop a list of pot entially useful alternatives. Finally,

preference cone theory is used to aid decision maker selection from these

nondominated alternatives. Each of these three technologies have been

developed elsewhere. This study considers aspects of appl ying these

technologies to cell formation decsisions. The procedure and its theoretical

underpinnings are explained step-by-step and illustrated in a four-objective,

four-cell, 24-machine, and 50-part cell formation problem. The example

c ontains 12 nondominated solutions and requires only four pairwise comparisons

of nondominated solutions by a decision maker before convergence to the

preferred solution. Computer processing requirements are not burdensome, and

decision maker participation is expected to be efficient.

From Job Shops to Manufacturing Cells

Abstract. This paper attempts to bring an understanding of what cellular

manufacturing (CM) is and is not, its advantages and disadvantages, the nature

of manufacturing cells in industry today, and the characteristics of parts

which are appropriate for CM. Additionally, the issue of whether readers

should consider converting some job shop operations to manufacturing cells and

how they c ould go about actually formaing the cells is discussed.

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