ACY air covering yarn refers to DTY yarn and spandex is fed in parallel into a specially designed air-jet core. Compressed air at a preset constant pressure is intermittently released through the jet, and the air dynamics wrap the filaments of nylon DTY twisting the spandex to form uniform network adhesion points; this process is called two-step spinning. Air covering yarns can also be processed in one step on an integrated machine using POY. This is called one-step spinning. One-step spinning is suitable for large-scale production and offers a price advantage. ACY yarns can be used in various textile products and are a primary category for the deep processing of elastic materials. Fabrics made from these yarns exhibit good elasticity, fluffiness, softness, and easy dyeability.

SCY single covering yarn, which involves pre-winding the outer layer of yarn onto the aluminum spool and securing these loaded tubes on rotating spindles. Once the machine starts, the spandex is set with an appropriate draw ratio, and the core spandex from the center hollow tube of the spindle is combined with the yarn end on the aluminum tube, and then guided into the stretching rollers. Due to the rotation of the spindle driving the aluminum tube, the outer yarn spirally wraps around the spandex, forming a tightly mechanically wrapped yarn. The material for single-covering yarn is versatile, including DTY, HOY, FDY, etc. Fabrics made from SCY yarn have clearer weave patterns, higher-quality appearance, a softer feel, and fewer fuzzies, making them more wear-resistant and anti-pilling. It is ideal for weaving elastic fabrics and materials.

Nylon 6 DTY is a type of elastic yarn with uniform elasticity and good stability, formed from POY filament after drawing and texturing.DTY can be further processed to produce differentiated yarns such as SCY yarn, melanged yarn, ply yarn, and ACY yarn. A large quantity of DTY yarn is directly used in the production of chemical fiber fabrics and textile products, with specifications ranging from 15D to 70D, filament count (10～48)f, and 78/48f and 55/48f mainly sold for use by seamless underwear manufacturers.

POY during the spinning process, the filament is partially stretched to obtain a precursor with uniformly oriented molecular chains. In order to obtain the characteristics of post process spring-loaded processing.
HOY compared to POY, the stretching is greater and the molecular chain orientation is higher. It can be directly used for weaving textiles or processed to obtain elastic materials with certain characteristics.
FDY refers to fully drawn yarn. During the spinning process, the filament is fully stretched and then heated and set by hot rollers, achieving good thermal stability. It can be used for further processing of yarns, such as producing SCY and DCY yarn, twisting or double yarn, and air-jet texturing. FDY can also be directly used for fabric production, with fine deniers below 12D suitable for hosiery or lightweight sheer fabrics. Other specifications are widely used in various textile fields including knitted, woven, and warp-knitted fabrics. The characteristics of these fabrics include good shrinkage stability, a high-end smooth surface, and a silky touch.