What are the differences between FDY and DTY yarns?

In the textile fiber industry, polyester filament is one of the most commonly used materials. In the processing of polyester filament, FDY and DTY yarns are two of the most common finished products.

What are FDY and DTY yarns?

FDY (Full Drawn Yarn) – Fully Drawn Yarn
FDY, also known as fully drawn yarn, introduces a drawing process during spinning to obtain a wound yarn with high orientation and medium crystallinity. Simply put, it is "fully drawn" during the production process.

DTY (Drawn Textured Yarn) – Stretch Textured Yarn
DTY yarn, often referred to as low-elasticity polyester yarn, is made from POY (pre-oriented yarn) as the base yarn, through stretching and false twisting. This processing gives DTY yarn a unique bulkiness and elasticity, making it the most widely used fiber material in clothing fabrics today.

Key Differences Between FDY and DTY Yarns

• Appearance Differences: FDY yarn has a very smooth and straight surface with tightly packed fibers, giving it a bright, metallic sheen. In contrast, DTY yarn undergoes a false-twist process, resulting in noticeable curls and waves, making it visually more voluminous and giving it a softer, more natural sheen.
  
  
• Hand Feel and Comfort Comparison: Due to its compact structure, FDY yarn typically feels stiffer and smoother, making it suitable for fabrics requiring a good drape. DTY yarn, with its looser structure, feels very soft and textured. Furthermore, the larger gaps between the fibers in DTY yarn significantly improve its warmth retention and moisture-wicking breathability compared to FDY.
  
  
• Elasticity Differences: FDY yarn undergoes extensive stretching during production, resulting in a stable molecular structure and virtually no resilience. DTY yarn (textured yarn) possesses excellent physical elasticity, stretching and quickly rebounding under stress. This makes fabrics containing DTY yarn less prone to deformation and provide a better fit.
  

Why is DTY yarn more popular in the market?

In practical applications, DTY yarn has a very wide range of users, mainly due to its unique physical properties:

• Excellent bulkiness: Through the false twist process, the internal fibers of DTY yarn are highly crimped, making the fabric not only breathable but also lighter and more comfortable to wear.
  
  
• Good coverage: Because DTY yarn is "fatter" than ordinary filament yarn, it provides better coverage and a thicker feel when weaving fabrics of the same density.
  
  
• Wrinkle resistance and abrasion resistance: Inheriting the toughness of polyester fibers, garments made from DTY yarn are less prone to wrinkling and are durable and abrasion-resistant, making them ideal for sportswear, home textiles, and casual wear.
  
  

Application Areas: FDY and DTY Each Have Their Own Roles

• FDY Applications: Due to its smooth surface and strong luster, it is often used to make imitation silk fabrics, curtains, high-end linings, and even industrial fabrics.
  
  
• DTY Applications: As an ideal material for knitting and weaving, DTY yarn is often used to manufacture knitted underwear, sweatshirts, T-shirts, blankets, and various decorative fabrics.
  
  

FDY yarn emphasizes "crispness" and "brightness," while DTY yarn focuses on "comfort" and "texture." When choosing raw materials, companies should decide based on the intended use of the end product. If you prioritize fabric elasticity, warmth, and a soft feel against the skin, DTY yarn is the best choice.