The influence of ring die on pelletizing 2
Die Hole Spacing
The die hole spacing is related to the properties of the pressed feed. For presses of feeds with minimal wear, a ring die with a close hole spacing can be used. For presses of feeds with high wear, such as those containing high mineral content or fibers, a ring die with a larger hole spacing should be used.
Die Hole Shape
The four main die hole shapes are straight, stepped, internally tapered, and externally tapered. Straight holes offer moderate performance, are easy to manufacture, and are the most commonly used. Stepped holes reduce die hole length and shorten material extrusion time. Internally tapered holes provide high extrusion density, high hardness, and low pulverization rate. Externally tapered holes facilitate pellet passage, offer low extrusion density, and low hardness.