The whole ring mold of the feed pellet machine is drilled on the finished ring mold ring, and the cross section of the hole is mostly circular. When pellet fuel is formed, the diameter of the holes is relatively small and metal processing is difficult. Therefore, the raw material in the hole is finely pulverized, and the friction between the raw material and the hole wall gradually increases to reach a certain molding density. When the hole diameter reaches 25 mm or more, metal working conditions are good and can be used for processing materials. The molding cavity should be processed with a feed bevel, a forming angle and a holding cylinder.

The sleeve ring mold of the feed pellet machine is designed on the basis of the overall ring mold, that is, the sleeve mold is set in the die hole, the purpose of which is to reduce the wear of the ring mold and improve the ring mold. It is used to process rod-shaped pellet fuel with a diameter of 25 mm or larger. The following technical factors should be considered in the ring mold for installing the sleeve: First, consider the processing accuracy of the "mother ring" of the ring mold. The advantage of the mounting sleeve is that the female ring does not require special alloy materials and does not require strict heat treatment.

The production of feed pellet machine casting technology has greatly reduced metal processing production. After the mold cavity is worn, only the sleeve is replaced without the mother ring, which greatly extends the maintenance cycle. This design requires better strength of the mother ring. Precision requirements are also high. The shrinkage and expansion coefficients of the material and the material of the mother ring are calculated and tested in detail, especially the non-metallic sleeves undergo rigorous engineering tests to ensure easy installation and removal. It has the highest strength and hardness. The inner hole of the sleeve should have a shape to ensure the molding quality, and the processing cost should be considered.