In the texturing process of nylon 6 POY yarn, twisting tension (T1) and untwisting tension (T2) affect the stability of texturing and the quality of nylon 6 DTY, which are important factors to ensure normal production.
If the ratio of T2/T1 is too small, the twisting efficiency will be low and the twisting will be uneven. If the ratio of T2/T1 is too large, the frictional resistance will increase, which will easily cause fibrils, broken ends and incomplete untwisting tight spots. The untwisting tension must be greater than the twisting tension. Otherwise, the filaments on the friction disc are in a loose state. The friction disc and filaments will easily slip, resulting in uneven twisting, tight spots and streaks. If T1>T2, streaks will appear in dyeing.
In summary, the twisting tension should be uniform and stable. Otherwise the nylon DTY will have obvious stiffness and poor elasticity and bulkiness. The twisting tension can be controlled at a lower standard, which can reduce the abrasion of the machine and make the texturing effect good and stable. However, if the tension T is too low, the filaments will make poor contact with the hot plate and jump, resulting in more broken ends. If the tension T is too large, the filament will break and fuzz and cause abrasion of machine parts. After experiment and production practice, the influence of process adjustment on T1 and T2 is summarized as follows:
1. With the increase of D/Y ratio, twisting tension T1 increases and untwisting tension T2 decreases.
2. As the drawing ratio increases, the twisting tension T1 increases and the untwisting tension T2 increases. But if the drawing ratio is too high, the twisting tension T1 will be greater than the untwisting tension T2.
3. As the texturing speed increases, the twisting tension T1 increases and the untwisting tension T2 increases.
4. As the temperature of the hot plate increases, the twisting tension T1 decreases and the untwisting tension T2 decreases, too.