What causes the shrinkage gap in the granulation ball?

Shrinkage voidage and hollow pellets indicate improper tempering of the wire. Mild contraction gap when may only be a small hole in particle on the end face, and serious when may produce hollow particles, like a swizzle stick, the emergence of this phenomenon is that line of core temperature close to molten state, and the line is expected to shrink immediately after cut grain, and properly tempering line material, the interface will maintain a constant temperature gradient, and no response when it was cut to the cooling medium.

The specific reason for the shrinkage gap is that when the processed water is too cold for a particular polymer, the outer layer of the wire freezes, creating a hard shell and leaving the heat in the core. In addition, line material in air or water, there is not enough soaking time, lead to the quantity of heat of wire core material cannot be transferred to line material surface, which can't be a good cross section of cooling, underwater pelletizing production of particles, because there are a trapped volatiles in the melt, also can appear shrinkage void, a kind of effective prevention measures is to check vacuum hole extrusion machine.

If you still want to know more information, welcome to consult changzhou zhuoqun nanomaterials co., LTD.