Last week we introduced you to what is the compression ratio of a pellet mill. Next we will introduce you how to choose the right die
First of all, in the premise of using high quality ring die, should be based on the specific gravity of the production material, the choice of suitable die hole form, opening rate and compression ratio (compression ratio = effective length of the die hole die hole diameter). In the premise of ensuring the strength of the ring die, try to improve the opening rate of the ring die, for some varieties of materials, under the condition of ensuring a reasonable compression ratio, the ring die is too thin walled, so that the strength of the ring die is not enough, the production will appear burst die phenomenon, at this time should ensure the effective length of the die hole premise, increase the thickness of the ring die and open additional decompression holes
The ring die compression ratio is the ratio of the effective length of the ring die hole and the minimum diameter of the ring die hole, which is an indicator of the extrusion strength of the wood chip pellet mill. The larger the compression ratio, the stronger the extruded wood chip pellets. For the straight hole of the ring die compression ratio, the effective length of the ring die hole is the total thickness of the ring die, the minimum diameter is the diameter of the die hole itself; for the release step hole and the outer cone hole, the effective length of the die hole is the total thickness of the ring die minus the length of the release hole or the length of the outer cone hole, the diameter of the small diameter section is the diameter of the hole for calculating the compression ratio; for the compression step hole and the inner cone hole, this situation For the compression step hole and the inner conical hole, this situation is rather special, generally the whole thickness of the ring die is taken as the effective length of the die hole, and the minimum diameter is taken as the aperture of the small diameter section, of course, the meaning of the compression ratio of the ring die calculated in this way is different from the first two situations.
Roughness is also an important indicator of the quality of the ring die. At the same compression ratio, the greater the roughness value, the greater the resistance to extrusion and the more difficult it is to dispense the pellets, and too much roughness also affects the quality of the pellet surface. A suitable roughness value should be between 0.8 and 1.6