A slot die is the most common type of spinning device used to make melt blown fibers. A pair of louvers was installed in the air flow field of a melt blowing die. Air velocity measurements were taken in the presence of the louvers and in the absence of the louvers. In some experiments, the louvers were parallel with the airflow. In other experiments, the louvers were angled relative to the airflow at angles up to 6 degrees. If higher air velocities can be achieved with louvers, then the melt blowing process can be improved.