1) Volume density: reflects the characteristics of fiber stacking;
2) The twist angle and curl of fibers: reflect the straightness of fibers along the yarn axis;
3) Number of strands and twist direction of the strand:
4) Linear density (diameter) and coefficient of variation: reflect yarn thickness and change
5) The force between fibers (friction coefficient, entanglement point, action segment or slip length, etc.): reflects the stability of the yarn structure