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.
5 sections 5 terms 6 sources ~4 min
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.