Leadtime estimation in a manufacturing shop environment

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Virginia Tech

This research examines the relationships between the independent variables; lot size, sequencing rule, and shop type/product mix and the â dependent variables; work-in-process, machine utilization, flowtime, and leadtime. These relationships have seldom been investigated by academicians. There is no satisfactory method available in the literature today that can be used to accurately estimate leadtime. This research developed methods for leadtime estimation. A leadtime estimation method would be invaluable to the production planner, for it would enable the person to decide when the job should be released to the shop.

The experimental system considered in this research is an eight machine shop. Three different shop types, a jobshop, modified flowshop, and a flowshop, were modelled. Each shop type had eight different product types being manufactured. Two different sequencing rules, SPT and FIFO, were used. The entire system was analyzed via simulation on an IBM P.C. using SIMAN system simulation concepts.