Other factors affecting the spinning quality and variety The following is still taking high-quality pure cotton yarn as the product object of necessity discussion in the roving process. Both are directly fed with non-twisted sliver, thereby omitting the roving process, free-end spinning without package twisting, direct winding forming eliminates the winding process, reflecting the short process, high productivity and automation High degree of excellent performance.

From the perspective of the draft distribution of the front and rear dual zones, the draft ratio of the small rear zone of not more than 1. From this perspective, ring spinning basically adopts single-zone concentrated drafting, and only rovings with twisted whiskers or even large twist coefficients can achieve large-scale and high-quality drafting in single-zone drafting.

However, the bottleneck of the spindle speed restricts the production capacity of the spinning frame in the past 30 years, which is almost stagnation. The technical economy and management constraints of super-large draft straight spinning are more, and the overall cost performance is lower. In multi-zone drafting, continuous drafting in the same direction will cause the draft wave generated in the previous draft zone to be superimposed on the draft wave generated in the next draft zone, seriously deteriorating the uniformity of linear density, roving to spinning process The sliver turn of the yarn can reduce the superimposition effect of the draft waves in the same direction, while the twist factor of the roving will also reduce the superposition effect of the draft waves in the same direction. In order to ensure the drafting quality,

the carding sliver of the Conventional Polyester Yarn process passes through three draw frames and is drafted, so that the number of process configurations between the carding and spinning processes is odd, making it conform to the classic 'odd number rule' of the spinning process. Another beneficial function of stepwise drafting by adding a roving process is often overlooked by the industry, and that is the turn of the sliver. 4.5 to 4 times.3. It adopts the three-roller three-apron super-large drafting device, which is directly fed from the untwisted cotton sliver with a diameter of 250 mm, and is suitable for spinning yarns larger than 20 tex (30 British counts).