A cutting deck for housing first and second cutting blades rotatable inside a cutting chamber is provided. The cutting deck includes a weldment including a top plate and side plates. The top plate includes first and second shaft reception orifices, and a flow control assembly extending away from the top plate to define an airflow channel between the flow control assembly and the side plates. The flow control assembly includes a first directional changing portion proximate to the first shaft reception orifice and a second directional changing portion proximate to the second shaft reception orifice. The first and second directional changing portions are separated from each other by straight portions. The first and second directional changing portions are passed over only by respective ones of the first and second cutting blades, and both the first and second cutting blades pass over the straight portions.
