ENGINEERING A CIRCUIT-BOARD ASSEMBLY LINE FOR A DESIRED CAPACITY AND FLOWTIME

This paper describes a study done to engineer a circuit board assembly line for a desired capacity and flowtime. The type of line studied is often referred to as a flexible flow line and is organized as a sequence of workstations, each with one or more identical machines. Many different types of boards are to be produced. Engineering requires determining the number of different types of machines needed, sizing the buffers, and determining the input lot sizes and loading sequence. All this is done based on the forecast of a typical Product mix, estimated processing times, and estimated machine downtimes. To achieve the desired flowtime, the in-process inventory must be tightly controlled with the adverse consequence of a loss in capacity. Three alternatives are explored for this purpose. The capacity is susceptible to long machine breakdowns as well as an unbalanced product mix. This study shows that proper lot sizing and sequencing can increase the capacity of the line by more than 10%.