AbstractWe propose a policy for controlling the release of raw wafers into semiconductor wafer fabrication lines. The proposed policy exploits up-to-date factory floor information gathered by tracking systems in order to calculate the timing and amount of new releases to minimize mean flow times and mean tardiness while maintaining the maximum output rates of the system. Extensive computer experiments show that the proposed policy results in at least 23.0 and 17.9% improvements on average in mean waiting time and mean tardiness respectively compared to existing release rules.