Abstract: Based on production practice, the paper analyzes the classification and causes of the draft waves during pure spinning and blending of differentiated fibers and puts forward solutions and measures for the process of production. Results indicated that excessive drafting force caused the main draft wave, which can be improved by reducing the roving weight and twist factor and combing with a large back draft gauge or a large back draft ratio. In addition, accidental drafting may result in multi-band drafting waves, long slubs, long thin places defects, or wrong yarn count, which can be solved by increased roving twist factor or decreased back draft ratio.

Key words: differentiated fibers; draft wave; drafting force; accidental drafting