The difference between DTY, FDY, and POY

DTY network filament: Network filament refers to a long filament with periodic network points formed by the entanglement of single filaments in the network nozzle under the action of jet airflow. It is made by using POY as raw material for stretching and false twisting deformation processing. It often has a certain degree of elasticity and shrinkage. The low elasticity network silk produced by combining network technology and DTY technology is characterized by both the fluffiness and good elasticity of the deformed silk, as well as many periodicity and network points, which improves the tightness of the filament, eliminates several textile processing steps, and improves the ability of the tow to pass through the water jet loom.
FDY fully stretched yarn (referred to as fully stretched yarn in Taiwan): By introducing stretching during the spinning process, a winding yarn with high orientation and medium crystallinity can be obtained, which is a fully stretched yarn. Conventional fully stretched fibers, including polyester and nylon, belong to the category of synthetic filament. FDY fabric has a smooth and soft feel and is often used to weave synthetic silk fabrics. It has a wide range of applications in clothing and home textiles. Synthetic fiber filaments further prepared by spinning and stretching. The fibers have been fully stretched and can be directly used for textile processing.
POY pre oriented filament: refers to a chemical fiber filament with an orientation degree between unoriented and stretched fibers obtained through high-speed spinning, which is not fully stretched. Compared with untwisted yarn, it has a certain degree of orientation and good stability, and is often used as a specialized yarn for drawing false twist textured yarn (DTY). 
Comparison of the three:
From an appearance perspective, DTY fibers are curly, POY and FDY fibers are straight, while FDY has better strength, while P0Y has slightly weaker strength. FDY is a fully stretched filament that is completed in one step by spinning and stretching. DTY is a stretch textured yarn that is processed by false twisting to give it a fluffy effect. POY is a pre oriented yarn that requires post-processing after spinning to have textile properties.