A pin-chain steaming-shrinking machine relaxes residual shrinkage under steam mid-line in dry finishing, while a pin-chain frame locks the width at the same time. Residual shrinkage release and width control take place before delivery, followed by decatizing to stabilise the finish. QL's WPF-LTYS is built this way, engineered with the QL Anti-Condensate Twin-Steam System, for worsted and woollen dry-finishing lines.
Where this machine sits in the line, and what comes before and after
The woven WPF-LTYS path is WPF-ZW straightening → pin-chain steam pre-shrinking → decatizing. Straighten the weft first, then hold the fabric edges at a set width during overfed steaming, followed by cooling before delivery.
The alternative is WPF-WDYS belt pre-shrinking → WPF-ZW straightening → decatizing. Choose controlled-width edge holding or relaxed belt conveying; they are alternatives, not consecutive machines. Decatizing is then selected from batch, continuous, continuous pressure and kier methods.
What it changes in the fabric, top or yarn: handle, dimensional stability, lustre, cleanliness
What this pin-chain steaming-shrinking machine changes is dimensional stability and surface cleanliness. Weaving and finishing lock stress into the fibre that releases on its own the first time the fabric meets water: relaxation shrinkage, irreversible, present in every fibre fabric. The independent overfeed system feeds in a set length of warp slack so the fabric can relax freely under steam heat, and the pre-delivery cold-suction unit then cool-fixes the result before delivery. The pin-chain frame holds width to the process-defined value from infeed to delivery. On cleanliness, the QL Anti-Condensate Twin-Steam System intercepts condensate at source — a heating bank keeps the steam in vapour state after it crosses the fabric, a suction unit evacuates it immediately, and vapour never dwells on the surface, so the fabric comes off free of water marks and colour spotting.
Why this machine is necessary: what happens without it, or with another method
WPF-LTYS serves woven routes that need width control during pre-shrinking. Pin chains hold the edges, overfeed allows lengthwise relaxation, and steaming followed by suction cooling completes the sequence. The QL Anti-Condensate Twin-Steam System manages steam and condensation.
WPF-WDYS instead allows free lengthwise and widthwise relaxation on a belt. Select the conveying method for width requirements, elasticity and downstream straightening position. In either route, pre-shrinking precedes decatizing and does not replace every subsequent setting operation.
Setting the parameters: temperature, tension, speed, time
Standard specification: effective working width 1,800 / 2,000 / 2,200 mm, operating speed 30 m/min, steam pressure 4–6 bar, air pressure 8 bar, installed power 23 kW. Warp overfeed — which sets shrinkage depth — steam volume, steam pressure and suction intensity are each configured to the fabric; exact settings are determined by trial — contact QL for the process data sheet. Temperature and tension figures are likewise set by trial for each quality.
The questions customers ask most
- How can under-steaming and uneven shrinkage on heavy-weight woolen double-face fabric be fixed?
- How is fabric protected from water-drip marks and colour spotting caused by steam condensation?
- If garments shrink after just one wash, how can this be fixed before the fabric leaves the mill?
- Belt-type preshrinking can let fabric width drift — how should I choose between the belt type and the pin-chain type?
- Which preshrinking machine should be used for knit fabric — is the pin-chain type (WPF-LTYS) only for woven fabric, or can it handle knits too?
- Is this the same thing as the mechanical pre-shrinking process sometimes used abroad?
Which process routes it appears on
Read WPF-LTYS in the context of these routes: worsted top-dyed, worsted piece-dyed, woollen stock-dyed, woollen piece-dyed. Follow each branch to understand the equipment choice; a required process does not mean every quality uses the same model.
Give QL the fabric or top sample, existing upstream and downstream stations, and target finish to review configuration and process connections together.