POY, FDY, HOY: The Filament Spinning Line and Its Speed Regime
The machine chain that turns PET melt into filament — from spin beam to high-speed winder — and how take-up speed alone separates POY, FDY and HOY. With real OEM series and typical ranges.
The entire character of a polyester fabric begins on the spinning line, where molten PET is drawn into fine filaments. This line is a machine chain whose sequence is almost universal: heated spin beam → metering (spin) pump → spin pack and spinneret → quench → spin finish → godets → high-speed winder. Yarn from this same chain can be POY, FDY or HOY; the essential difference is not the machine but the take-up speed regime. How the polymer chemistry (PET, IV) arrives at this melt is covered in our pet-polymer-iv guide, and the physics of how take-up speed sets molecular orientation is covered in melt-spinning-poy-fdy; here the focus is the machine and the line itself.
Along the line: from spin beam to winder
Molten PET is distributed from the heated spin beam to each spinning position. At every position a metering pump pushes the melt into the spin pack at a constant, measured throughput — this pump is the critical organ that governs count (dtex) consistency. Inside the pack the melt is filtered and forced through a spinneret of thousands of capillaries, forming a filament bundle. The hot filaments solidify immediately in the quench zone; spin finish (yarn oil) is then applied to control static and friction. The filaments wrap onto godets and finally form the package on the high-speed winder. The final godet speed sets the take-up speed, and that is precisely what determines the yarn class.
- POY (partially oriented yarn): take-up speed typically ~2,500–3,500 m/min. The filament is not drawn on the line; it is a partially oriented, high-elongation intermediate, and is almost always feedstock for DTY texturing.
- FDY (fully drawn yarn): typically ~4,000–6,000 m/min. The drawing step is integrated into the line (drawn between heated godets), so the yarn emerges low-shrinkage and dimensionally stable; it is used directly in knitting and weaving.
- HOY/FOY (highly/fully oriented yarn): typically ~5,500–6,000+ m/min. The high take-up speed produces meaningful orientation even without drawing; it is a more niche regime.
Why this speed ladder yields low orientation in POY and dimensional stability in FDY — that is, the relationship between molecular orientation and take-up speed — is treated in melt-spinning-poy-fdy. How POY becomes bulky, stretchy DTY is the subject of dty-textured-yarn.
Real OEMs and series
In filament spinning machinery the global reference is Oerlikon Barmag (Germany). The WINGS platform integrates the take-up godets directly into the winder, simplifying the line layout, with typically ~30% energy savings reported; WINGS POY and WINGS FDY configurations are offered with different position/end counts. Barmag's EvoQuench radial (inward) quench uses markedly less process air than cross-flow quench — representatively on the order of ~60–80% less — especially for microfilament; the specifics of microfilament spinning are in microfilament-science. The premium alternative is TMT Machinery (Japan): the ORCA POY lines and the ATi-MANTA-II FDY with its I-Box draw zone are well-known series. The spinneret design that sets the cross-section geometry — round, trilobal, hollow — is covered in fiber-cross-section.
Positions and ends: the capacity lever
A spinning machine's output scales largely with its position and end count. POY machines typically carry 10–24 ends per position, while FDY counts are usually lower (≤~32, because the draw godets need room). Spinneret capillaries are typically ~0.2–0.4 mm and capillary throughput on the order of ~0.5–5 g/min; spinneret/pack temperature runs in the ~235–295 °C range. On FDY lines the first godet (GR1) is typically ~65–90 °C and the draw godet ~108–130 °C. All of these figures are typical/representative ranges; actual values vary with product, OEM and line configuration.
POY · FDY · HOY compared
| Property | POY | FDY | HOY/FOY |
|---|---|---|---|
| Typical take-up speed | ~2,500–3,500 m/min | ~4,000–6,000 m/min | ~5,500–6,000+ m/min |
| Drawing on the line | No (undrawn) | Yes (in-line integrated draw) | No (high speed orients) |
| Orientation / shrinkage | Partially oriented, high elongation | Highly oriented, low shrinkage | Highly oriented |
| Typical use | Feedstock for DTY texturing | Direct knitting/weaving; stable | Niche; selected applications |
| Typical ends/position | ~10–24 | ≤~32 | Variable |
In short: the machine chain of the filament spinning line is fixed; what differentiates the output is take-up speed. POY is an intermediate for DTY; FDY, drawn on the line, gives a stable, directly usable yarn; HOY holds a more niche position through the orientation that high speed alone provides. To understand why a yarn shows a particular hand, stretch and dimensional behaviour, knowing which regime the line ran is the first step.