The depth of the die hole is the diameter of the ring die of a certain thickness minus the length of the release hole, and the size of the hole diameter forms a certain aperture ratio. The effective hole length divided by the effective hole diameter is equal to a multiple of the compression ratio (diameter to length ratio). See the die hole compression ratio:
The shorter the effective hole, the smaller the diameter-to-length ratio, the smaller the squeezing force of the material in the die hole, and the shorter the squeeze time. It is easy to extrude materials, high production efficiency, low power consumption, but the quality of the particles produced is loose, which is easy to cause high powder content, uneven particle length and other quality problems.
The longer the effective hole, the larger the aperture ratio, the greater the extrusion force of the material in the die hole, and the longer the extrusion time, the lower the production efficiency. The power consumption increases accordingly, and the particles produced are hard and strong.
With the lengthening of effective holes, the granulation output obviously decreased, and even the plugging of the mold did not produce granules.
In order to obtain the best granulation performance and make the output and quality reach the best state, it is very important to choose a good ring die compression ratio.
Each granulated material has a relatively suitable aperture ratio during granulation. According to the comprehensive factors of the nature of various raw material formulations, crushing particle size, mechanical properties, etc., the ring die compression ratio should be selected reasonably.
If the ordered ring die aperture ratio does not fit the granulation requirements of the formula well, it is necessary to adjust the formula materials appropriately, because the ultimate goal is to achieve the best granulation efficiency.