Вазьміцеся за гэтыя дзве кропкі для камбінацыі шруб
Continuing with the previous topic, we will talk about screw combination in this section. In fact, for nylon toughening modification, compared with nylon fiber reinforcement or nylon flame retardant reinforcement, its requirements for screw combination are relatively simple.
But we want to emphasize two points
the aspect ratio of the twin-screw extruder used for nylon toughening modification should be longer, and it is recommended to be 44:1.
What is the benefit of a longer length-to-diameter ratio, that is, when the total cutout blocks are designed and the total number remains unchanged, if the length-to-diameter ratio is relatively long, it is conducive to the comparison of dispersing the combination of the cutout blocks Open, avoid 5 to 6 or more cutouts strung together.
As a result, the local resistance is very large, and then excessive shear heat is generated in this area, thereby destroying the performance of the material.
For nylon toughening, the screw combination should achieve the best effect on it, which is good dispersion and plasticization, and at the same time, the shear should be lower, that is, low shear.
So how to do it, first of all, we must grasp one point, that is, try not to use such high-shear threaded elements with a thickness of 90 degrees, or some threaded elements with reverse shear and relatively large resistance.
Then I usually recommend to use a small angle, and then combine the threaded elements with relatively thin slices, so that the shearing is relatively low while ensuring sufficient plasticization and dispersion, so the performance of the entire nylon after processing is greatly improved. It will be better to keep.
There is still a lot about the combination of this screw, let's get to know it together in the next section.