What are the main causes of yarn defects?

thick knots

cause

The length of common slubs on the cloth surface varies: mostly from 1 cm to 2 cm, the thicker ends at the middle are tapered, and most of them are poor drafting of the spun yarn, free flying flowers attached around the drafting zone, uneven roving strands, and roving defects attached. , It is caused by improper setting of winding clearing parameters; a small part of it is caused by poor spun yarn splicing or poor splicing of the winder. The details are mainly caused by poor yarn drafting and poor winding splicing.

solution

For thick knots and details caused by poor drafting of the spun yarn, it can be prevented and solved from the following 4 aspects:

1) Reduce the roving twist, that is, try to use a small roving twist without increasing the end break;

2) Ensure that the spinning and roving drafting elements are in good condition, maintain a proper rubber roller grinding cycle and apron replacement cycle, and check whether there are grooves, scratches and other problems at any time, and solve them at any time;

3) Maintain a constant temperature and humidity to avoid short-term and large fluctuations;

4) Optimize the spinning process, mainly the consistency of the gauge, the position of the upper pin and the pressure of the cradle. The thick knots and details produced in the spinning process can only be removed by the winding clearer, which will cause the increase in the number of cuts of the clearer. Special attention should be paid to the quality of the splicing to avoid the secondary formation of thick splicing due to poor splicing. Sections and details.

Uneven dryness

cause

The cloth surface presents regular or irregular even shadows; it is mainly caused by abnormal operation of drafting elements (cots, aprons, rollers), rough surface irregularities, cot entanglement spinning and backward spindles, etc. .

solution

1) Optimize the process of the drafting zone and maintain a good state of the rubber roller and apron;

2) Control the number deviation and evenness of the single and roving, and isolate it in time if abnormalities are found;

3) Repair the broken and abnormal spindles of the spun yarn in time, and require the turner to report abnormal situations such as rubber rollers, aprons, rollers, etc., and notify relevant personnel for handling;

4) Set the number variation and bead chain yarn defect cutting and alarm parameters for the yarn clearer on the winder, which can cut out the defects and reject the problematic bobbins.