The broken ends of spinning yarn can be divided into two categories: broken ends before yarn forming and broken ends after yarn forming.
The break ends before yarn forming refers to the breakage of the yarn before the output of the former nippers, which occurs in the feeding and drafting parts. The main causes are: broken roving, empty roving, sliver running out of the collector, collector blocking, gathering in the leather ring, filament winding roller and roller, etc.
The broken ends after yarn forming refer to the broken ends of the yarn segment from the front roller output to the barrel during the twisting and winding process. The causes are: abnormal twisting and winding machine parts (such as spindle vibration), jumper tube, traveller flying ring, abnormal balloon shape (too large, too small or skewed balloon), poor operation，blocked cotton flute or low vacuum, temperature and humidity are not well controlled, etc.
In addition, when yarn strength decreases and yarn strength irregularity increases due to the fluctuation of raw material properties, unreasonable process design and poor semi-product structure, the number of broken ends increases.
Under normal conditions, there are fewer broken ends before yarn forming. In production, the broken ends are mainly after yarn forming.