Doubling is the preparation process of twisting. Its task is to combine two or more single yarns (usually no more than five) and wind them into bobbins.
After doubling, the number of strands per yarn can be guaranteed, the tension of each single yarn can be balanced, the uneven twist of strands can be reduced, the strength of strands can be improved and the appearance can be improved.
There are two forms of yarn doubling: tube-yarn combining or tube-yarn combining. For example, tube-yarn combining can reduce the winding process, but because of its more tube changing times, it not only increases the labor intensity of the lathe workers, but also reduces the labor efficiency, so the textile enterprises generally adopt tube-yarn combining.