
Just like any other yarn, Air Covered Yarn also experiences some faults which are caused mainly by two issues – Positional Faults and General Faults. Below are some of the faults that are seen in Air Covered Yarn.
- 1. Filamentation:
- a. Positional causes:
- i. Damaged/worn guides
- ii. Dirty heaters
- iii. Damaged friction discs
- iv. Waste on feed rollers/bowl
- v. Misthreading
- vi. Mechanical damage to supply yarn
- b. General Causes:
- i. Draw ratio too high
- ii. Heater temperature too high
- iii. Speed ratio too high
- iv. D/Y ratio too low
- v. Supply type/finish unsuitable
- a. Positional causes:
- 2. High break rate
- a. Positional causes:
- i. Worn nip rollers
- ii. Supply package misaligned
- iii. Damaged friction discs
- iv. Misthreading
- v. Damaged or badly wound supply yarn
- b. General Causes:
- i. Speed too high
- ii. Draw ratio in correct
- iii. D/Y ratio too high or low
- iv. Heater temperature too high
- v. Ambient conditions incorrect
- vi. Supply type/finish unsuitable
- a. Positional causes:
- 3. Tight spots
- a. Positional causes:
- i. Worn nip rollers
- ii. Incorrect threading
- b. General Causes:
- i. Unstable process specification
- ii. D/Y not optimum
- iii. Supply irregularity
- a. Positional causes:
- 4. Dye/Bulk variation
- a. Positional causes:
- i. Heater temperature fault
- ii. Heater cold top (dark dye)
- iii. Damaged friction discs
- iv. Incorrect twisting unit speed
- v. Damaged or worn guides
- vi. Take-up tension variation (bulk)
- vii. Worn/damaged nip roller
- b. General Causes:
- i. Unsuitable process specification
- ii. Dirty heaters
- iii. Supply irregularity
- a. Positional causes:
- 5. Webbing/ overthrows
- a. Positional causes:
- i. Misaligned cradle
- ii. Stroke too long
- iii. Loose or worn traverse guide
- iv. Wear or damage in traverse box
- v.Cradle catching on feed, back arm
- vi. Point of origin guide not central
- b. General Causes:
- i. Take-up tension too high
- ii. Wind angle too low
- iii. Taper angle too low
- iv. Radial disturbance too high
- v. Axial displacement very high
- a. Positional causes:
- 6. Poor package unwinding
- a. Positional causes:
- i. Stroke length incorrect
- ii. Cradle settings incorrect
- iii. Filamentation in textured yarn
- iv. Yarn coming out of traverse guide
- v. Package webbed
- b. General Causes:
- i. Take-up tension too slow
- ii. Wind angle too high
- iii.Taper angle too low
- iv. Incorrect oil
- v. Filamentation in textured yarn
- vi. Radial / axial disturbance link out of phase
- a. Positional causes: