Wip balance and due date control in a wafer fab with low and high volume products

For a customer-oriented wafer fab, low volume products such as development lots or customer samples are often more critical than high volume products with regard to cycle time and delivery reliability because of due date commitment. In this study, a global rule combining WIP balance and due date control is developed for a wafer fab with low and high volume products. The purpose is to figure out the following two issues. Firstly, whether WIP balance of high volume products takes the cost of due date of low volume products. Secondly, how to make the trade-off between on-time delivery and WIP balance for the low volume products.