From POY to DTY: The False-Twist Texturing Machine
The draw-texturing machine converts flat, low-bulk POY filament into stretchy, bulky DTY. Its sequence of draw zone, heater, cooling, false-twist unit and intermingling jet sets the yarn's bulk, stability and torque, and therefore the hand of the finished fabric.
POY (partially oriented yarn) leaving melt spinning is flat, glossy and low in bulk; it lacks the stretch and fullness that knitting or weaving needs. The draw-texturing machine turns this feedstock into DTY (draw-textured yarn) by doing two jobs in a single pass: it draws the yarn to complete its molecular orientation, and it false-twists it to imprint a permanent crimp memory into the filaments. DTY is the single largest category of polyester filament yarn. For a fabric producer these machine parameters are not abstract; they are the direct source of the hand, cover and stretch behaviour you read in a TDS. See the dty-textured-yarn guide for the yarn property itself, and melt-spinning-poy-fdy for how the POY is spun in the first place.
The line sequence: draw → heater → cooling → twist → set → intermingle
The texturing machine is a series of zones the yarn passes through in order. First comes the draw zone: a speed difference between two feed rollers draws the POY, typically at a ratio of about 1.5–1.7, completing its molecular orientation and strength. The yarn then enters the primary (texturing) heater, which prepares the crimp to be heat-set; its operating temperature is representatively in the ~190–220 °C range. The hot yarn is taken below its glass-transition temperature on a cooling plate — this is where the twist 'freezes' in. The cooled yarn then reaches the false-twist unit.
The false-twist unit is the heart of the machine. On modern machines this is a three-axis friction-disc stack (polyurethane and ceramic discs); pin-type and crossed-belt systems are also used. The unit imposes intense twist on the yarn, but the twist is 'false': once the yarn passes the unit the twist runs back out, leaving behind the heat-set permanent crimp memory. An optional second (set) heater, representatively at ~160–180 °C, relaxes and stabilises that crimp. Finally an intermingling jet — a field dominated by independent jet makers such as Heberlein — uses compressed air to knot the filaments together at intervals, keeping the bundle coherent.
D/Y ratio sets bulk; set vs non-set sets the stability-torque balance
Two settings define the yarn's character. The first is the D/Y ratio: the surface speed of the friction disc relative to yarn speed, representatively ~1.6–2.2. The higher this ratio, the more twist is applied and the more bulk/crimp results; this is the primary bulk lever. The second is the set vs non-set choice. Set yarn passes through the second heater: it becomes low-torque, stable, softer and less prone to twisting (spirality) in the knitted tube. Non-set yarn skips this step: it stays high-torque and highly elastic, which is wanted for some stretch constructions but raises the spirality risk if the structure is not balanced.
Intermingling level is also a design decision, expressed in nips (knots) per metre: representatively NIM ~0–10, SIM ~40–60, HIM ~100–120+ nips/m. Higher intermingling holds the bundle tighter (reducing fraying in weaving/warp feeding), while lower intermingling gives a fuller, softer hand in knitting. Texturing speed is typically ~600–1,200 m/min and machine position count representatively ~216–448; the position count is a productivity/cost lever.
Real OEMs and series
- Oerlikon Barmag (Germany) — market-leading draw-texturing machines: the eFK and eAFK series (eAFK Evo, eAFK HQ) plus the multi-spindle eAFK Big V; WINGS HD winding integration.
- Himson (India) — HSS-AX series rooted in Scragg/TMT-licensed heritage, with high position density and a large installed base.
- TMT Machinery (Japan) and SSM/Saurer — premium texturing and advanced yarn processing (SSM also covers ACY air-covering and air-texturing).
- Heberlein (Switzerland, independent since 2023) — the dominant supplier of intermingling/air-texturing jets; HemaJet and (with KARL MAYER) WarpJet-KV jets.
Parameter → fabric effect: set vs non-set DTY
| Property | Set DTY (2nd heater used) | Non-set DTY (no 2nd heater) |
|---|---|---|
| 2nd (set) heater | Used (~160–180 °C, representative) | Skipped |
| Torque | Low — balanced | High — lively/torquey |
| Dimensional stability | Higher | Lower |
| Spirality tendency (in knits) | Less | More (unless structure is balanced) |
| Hand | Softer, settled | Stretchier, more active |
| Typical use | General knit/weave, stable fabrics | Stretch / high-elongation structures |
Why a buyer should care
The same POY feed yarn yields completely different fabrics depending on the texturing-machine settings. High D/Y + non-set gives a lively, stretchy hand; moderate D/Y + set gives a stable, settled fabric. Intermingling level shifts surface fullness and downstream behaviour. That is why understanding why a fabric family has a particular stretch/recovery/hand profile often traces back to yarn texturing. See our dty-textured-yarn guide for the yarn's final properties, and the guides weighing ATY and ACY alternatives for structures that want a loop or an elastane core instead of crimp.