Drawing process: causes and preventive measures for 6 types of defects

01 Hang flowers and insert cotton sliver

Causes: Mainly due to the unevenness of each channel, rupture of the sliver tube, aging of the suction bucket leather strips, etc.

Preventive measures: Each channel is polished smooth and without burrs, broken sliver cans are repaired in time, aging leather strips are replaced in a timely manner, and operation patrols are strengthened to remove them promptly when found.

Impact on subsequent processes: causing roving breakage or bad roving, as well as slubs or wrong wefts on the fabric surface.

02 thick and thin strips

cause:

① The automatic stop fails, resulting in too many strands or too few strands;

② The sliver is pleated and fed after the machine, the lap is too long or the pressure is poor, etc.;

③ The cotton sliver is too long or too short due to poor wrapping, and the wrapping is too tight.

Precaution:

① Electrical failure should be repaired in time;

② Earnestly implement operating methods and strengthen patrols;

③ Strengthen mechanical inspection and repair;

④ Do a good job of preventing defects.

Impact on subsequent processes: causing roving breakage and wrong weft defects.

03Impurity Strips

Cause:

① The cleaning work is not timely, the cleaning method is incorrect, and there are slapping problems;

② The air suction bucket or the return flannel cloth fails.

Precautions:

① Carefully follow the cleaning schedule to complete all cleaning tasks in a timely manner, and do not pat when cleaning;

② The air suction hopper or rotating flannel should always be kept in good condition.

Impact on post-processing: causing roving breakage and slub defects.

04 tops

cause:

① The surface roughness value of each part of the cotton sliver and cotton mesh channel is relatively high and there are flowers hanging;

② The mouth of the sliver tube is rough;

③ The sliver can capacity is too full;

④ The humidity in the workshop is too low;

⑤ The surface roughness value of the upper and lower rollers is relatively high.

Precaution:

① Strengthen equipment maintenance and refurbishment or replacement of sliver cans;

② Drop the bobbin according to the fixed length;

③ Strengthen temperature and humidity management;

Impact on post-processing: causing uneven dryness and slub defects.

05Greasy strips

Cause:

① Improper oiling of rubber rollers or coil gears;

② The tampon falls to the ground and is stained;

③ Oil hand joint;

④ The drafting part is not wiped clean when wiping the car flat;

⑤ Oil leakage from gear box or pinion box.

Precaution:

① Strengthen inspections and wipe away oil stains at any time;

② The oily hand does not hold the tampon, does not join it, and the tampon does not fall to the ground.

Impact on the post-processing process: causing oil warp and oil weft defects on the fabric, affecting the quality of the machine.

06 Severe unevenness

cause:

① Poor pressure or rubber roller and roller beating, rubber roller skew, concave center, lack of oil, big and small ends, etc.

② Wrapping rubber rollers, wrapping rollers and failing to remove the thin strips after wrapping.

③ The drafting gear is poorly engaged, worn out or has missing teeth.

④ The top roller has a concave center and a large number of flowers; the top roller is not pressurized enough, or the pressure roller deviates from the center of the top roller, or the pressure difference between the two ends is too large; the rollers move at intervals; the top roller or the bottom roller is wrapped with thin flowers.

⑤ The pressure rod is bent and deformed, the position of the pressure rod is too low, and the control force on the cotton web is too strong, resulting in the problem of inability to stretch.

⑥ The bearing is damaged.

⑦ The tooth shape error of the drafting gear is too large, and the radial runout of the ring gear is large.

⑧ The drafting gear key is loose.

⑨ The air suction and cleaning effect is not good, and flying flowers are caught in the cotton net.

Precautions:

① Strengthen equipment maintenance and inspection;

② Remove the thin strips when you find rubber rollers or rollers.

Impact on post-processing: causing large-area quality degradation, uneven dryness and regular defects on the cloth surface.
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