Fiber & Raw Material Engineering

Synthetic Fiber Extrusion Draw Ratio Tool

Drawing aligns the polymer chains. The ratio sets tenacity, elongation and final linear density together.

Godet Speeds Draw zone
m/min
m/min
Yarn Build As-spun
den
no.

Draw Ratio

— x

Draw godet speed divided by feed godet speed

Drawn Yarn

Drawn Denier
— den
Drawn Tex
— tex
Denier per Filament
— dpf
Applied Extension
— %

Draw ratios above the natural draw ratio of the polymer cause filament breaks. For PET, useful ratios normally sit between 3.0x and 4.5x.

Synthetic Fiber Extrusion Draw Ratio Tool — free, with the formula and a worked example, at Textile School.