FDY refers to filament, also known as fully drawn filament.

POY, also known as pre-oriented yarn, refers to the partially drawn chemical fiber filament with orientation between Unoriented Yarn and drawing yarn obtained by high-speed spinning.

The filament is FDY and the low elasticity is DTY.

Compared with unstretched yarn, it has a certain degree of orientation and good stability, and is often used as the special yarn for drawing false twist textured yarn (DTY).

Stretched textured yarn (DTY), pre-oriented yarn (high-speed spinning) (POY), fully drawn yarn (one-step spinning and stretching) (FDY).

Low-elastic yarn is a kind of polyester chemical fiber textured yarn, which is spun into polyester pre-oriented yarn (POY) from polyester chips (PET) at high speed.

Bulk material: DTY is a kind of textured polyester fiber. It is made of polyester chips (PET) by high-speed spinning polyester pre-oriented yarn (POY) and then drawing and false twisting. It has the characteristics of short process, high efficiency and good quality.

It has the characteristics of high breaking strength and elastic modulus, excellent heat setting, good resilience, heat resistance, light resistance, corrosion resistance, easy washing and quick drying, and also has the characteristics of high bulkiness, good heat insulation, comfortable hand feel and soft luster.

References:

Baidu Encyclopedia-Polyester Low Elastic Yarn