The first two main factors that affect the yarn strength are:
1. Fiber performance: the higher the fiber strength, the finer the fineness and the longer the length, and the yarn strength can be higher. The natural twisting of cotton fiber, wool and the curl of chemical fiber will increase the cohesion between the fibers when the yarns have little twist, thus improving the yarn strength. Short fiber content has great influence on the yarn strength.
2. Yarn structure: yarn fiber transfer in the radius direction and uniform structure when the yarn strength can be improved; yarn strength is reduced when layered fiber arrangement and folding, buckling and has hook,; when below the critical twist, the yarn strength increased with the increase of the twist; when above the critical twist, it descended with the increasing of twist. The yarn spun with different spinning methods has obvious differences in strength because of its structure.