Uncoiler and Recoiler: How Coil Feeding Equipment Works

An uncoiler unwinds a steel coil into a processing line under controlled tension, while a recoiler does the reverse — rewinding processed strip back into a coil. Both use hydraulic mandrel expansion to grip the coil's inner diameter, and both are built around the same core need: keeping material flow smooth and consistent through the rest of the line.

Feed mechanism: mandrel expansion

The mandrel expands hydraulically inside the coil's eye to grip it securely, then rotates to pay out (uncoiler) or take up (recoiler) material as the line runs. Pressing arms hold the outer wraps down during uncoiling to stop the coil from loosening or telescoping as it unwinds — a common cause of line stoppages if left unmanaged.

Tension control basics

Consistent tension is what keeps strip tracking straight through downstream equipment like levelers and slitting heads — our plate leveler guide covers what that stage corrects. Variable-speed drives synchronize the uncoiler or recoiler's rotation speed with the rest of the line, adjusting in real time so the strip neither goes slack (which causes wander) nor over-tensions (which can stretch or mark the material).

Specifications

• Coil weight: 5 to 60 ton
• Coil width: 152–1829 mm
• Coil OD: up to 1400 mm
• Thickness: 0.4–3.4 mm
• Drive: hydraulic, electric, VFD

Where they fit in the line

Uncoilers sit at the entry of slitting lines, blanking lines, and general sheet processing lines, feeding raw coil into the process. Recoilers sit at the exit, taking finished strip or sheet and rewinding it for storage or shipment. In continuous lines, both may run alongside turnstiles — covered in turnstile equipment in coil and strip processing lines — and levelers to keep the full sequence — unwind, level, process, rewind — moving without manual handling in between.

Sizing for your line

Coil weight and OD range are the first filter: undersized equipment risks mandrel slippage or structural strain, while oversizing adds unnecessary cost. Beyond capacity, check that the drive type (hydraulic, electric, or VFD) matches your line's speed and synchronization requirements — VFD control gives the finest speed matching for lines running multiple pieces of coordinated equipment in sequence.

Common issues from poor coil feeding

Most line stoppages traced back to the uncoiler or recoiler come down to two things: a coil that telescopes because the pressing arms weren't holding the outer wraps firmly enough, or strip tracking that wanders because tension wasn't matched to the line's actual running speed. Both are addressable at the specification stage — pressing arm force and tension control range should be checked against the thinnest and widest material the line is expected to run, not just the typical job, since thin or wide strip is usually where tension control is hardest to hold.

Coordinating uncoiler and recoiler speed

In lines where both units run together — unwinding at the entry and rewinding at the exit — their speeds need to track each other as material passes through intermediate processing. A mismatch, even a small one, either overtensions the strip or lets it go slack somewhere in the line. VFD-equipped units handle this synchronization automatically once configured, which is one reason VFD drive is worth the added cost on lines with multiple pieces of coordinated equipment rather than a single uncoiler running in isolation.