Optimization of queuing theory wait time through multi-skilled worker assignments

Operator allocation is a key aspect of manufacturing with both direct and indirect implications on system performance. Resource capacity must be managed carefully while still considering human factors like probability of operator error, job satisfaction, and worker (and skill) retention. In many cases human resources are flexible in their ability to handle various types of jobs, and this condition is favorable because it makes the system more robust in the face of disruptive events. Unfortunately, the benefits of worker flexibility may not be fully understood or utilized on account of the many sources of variability that exist and confuse the outcome of worker allocation decisions. The purpose of this work is to quantify the effect of varying rework rates of differently-trained employees working on multiple products. Subsequently, the time that inventory spends waiting in queue is minimized through optimization of worker placement.