What Size Decoiler Do You Need for Your Coil?

The Five Key Parameters for Decoiler Sizing

Before you can answer "what size decoiler do I need?", you must define five parameters based on your coil specifications. Each parameter independently constrains the decoiler selection:

Step 1: Determine Coil Weight Capacity

Coil weight is the most critical parameter for decoiler sizing. The decoiler must have a load capacity that exceeds your heaviest coil by at least 20% for safety margin. Here is how coil weight influences decoiler design:

• Light duty (≤1 ton): Manual-expanding mandrel, simple support arms, typically used for narrow strip (50–200 mm width) in small press shops. Suitable for prototyping, jewelry, and small part production
• Medium duty (1–5 tons): Hydraulic-expanding mandrel, motorized expansion, integrated hydraulic arm control. The most common category for general stamping shops producing automotive, appliance, and hardware components. FANTY's medium-duty decoilers serve the majority of our 200+ installed lines
• Heavy duty (5–15 tons): Heavy-gauge steel frame, reinforced mandrel with dual support, servo-driven expansion, integrated coil loading car. Used in automotive body panel, structural component, and large appliance production
• Extra heavy (15–30 tons): Dual-mandrel design with independent hydraulic systems, heavy-duty gearbox, and reinforced base plate. Used in steel service centers, automotive OEM lines, and heavy industrial stamping

FANTY's decoiler range covers capacities from 500 kg to 30 tons, all CE-certified and manufactured in our 45,000 m² ISO 9001 facility.

Step 2: Match the Coil Width to the Decoiler

Coil width determines the distance between the decoiler's side guide plates (also called guide arms). Proper side guide alignment keeps the strip centered as it uncoils and enters the straightener or feeder. Key rules for width matching:

• The decoiler width capacity must exceed your maximum coil width by at least 50 mm for side guide adjustment range
• If you run multiple coil widths, choose a decoiler with motorized or quick-adjust side guides to minimize changeover time
• Narrow coils (under 100 mm) require specialized guide inserts or centering cones to prevent strip wandering
• Wide coils (over 800 mm) need reinforced guide arms and additional support rollers to prevent sagging
• For progressive die operations with tight strip guidance requirements, consider adding photoelectric edge guide sensors that adjust the decoiler position automatically

Step 3: Consider Coil ID and Mandrel Expansion Range

The mandrel is the heart of the decoiler. It expands outward to grip the coil's inner diameter securely. Standard mandrel expansion ranges are:

• 300–450 mm ID: Common for small to medium coils. Typical mandrel range: 280–320 mm expanding to 380–420 mm. Available with 3-segment or 4-segment expanding leaves
• 450–508 mm ID: Standard for medium to large coils. Mandrel range: 420–460 mm expanding to 500–530 mm. This is the most common ID range in the stamping industry
• 508–610 mm ID: Large coils, often used in automotive lines. Mandrel range: 480–520 mm expanding to 580–630 mm. Requires high-torque hydraulic expansion mechanism

FANTY's decoilers feature proprietary 4-segment expanding mandrels with hardened steel wear plates for long service life. Each mandrel is precision-machined to ensure concentricity within 0.1 mm, minimizing coil vibration during uncoiling.