Feed pellet machine pressed out of the particle size is not the same thickness is generally caused by the following reasons: 
1 raw material mix will lead to uneven pressure of particles of different thickness. This is the pressure due to raw material mix if uneven, so that when the mixture through the die, given by the pressure roller is not the same, so the pressure out of the particle hardness and thickness are not the same. 
2 modulation uneven, for the same reason. 
3 feed pellet machine press roll elastic is not the same. Check the pressure roller are loose, and keep the pressure roller and ring die pellet same gap. 
4 the ring mold and the edge of the intermediate pore size is not the same aperture. This usually is the quality of the ring mold itself, the proposed replacement ring mold. 
5 ring mold hole clogged, causing secondary granulation hole, you can try to clean clogged holes turned around. 
6 granulation current instability will lead to this situation.