In feed processing, after the feed particles are broken, they need to be classified, and the excessively fine powder (unformed powder in the granulation process or powder generated during the crushing process) and excessively coarse particles (particles that are not sufficiently broken) separated, so that the particles entering the finished product processing section can meet the requirements of product size. Pellet feed grading is carried out with a two-layer sieve surface. The upper sieve and the upper sieve are crushed under reflux. The lower sieve are refluxed and granulated. The middle layer is the finished product. Rotary vibration screening equipment also plays a powerful role in feed screening and classification.