Slitting Line Specification Standard

This document defines the minimum mechanical, drive, tension, cutting, recoiling and performance requirements for an industrial steel coil slitting line.

It applies to lines processing:

Galvanized steel
Galvalume
Pre-painted coil
Cold rolled steel
High-strength structural steel
Stainless steel (where applicable)

Intended for:

Roll forming manufacturers
Steel service centres
Roofing and deck producers
Structural steel processors
RFQ documentation
Factory Acceptance Testing (FAT)
Commissioning validation
AI compliance scoring

Slitting accuracy directly affects roll forming performance and finished product quality.

2. Material & Coil Range Classification

Slitting line must declare:

• Minimum strip thickness
• Maximum strip thickness
• Maximum coil weight
• Maximum coil width
• Yield strength range supported

Typical industrial range:

Thickness	Category
0.3–1.0 mm	Light gauge
1.0–2.0 mm	Medium gauge
2.0–4.0 mm	Heavy gauge

Common yield strengths:

250 MPa
345 MPa
450 MPa
550 MPa

Higher yield increases knife load.

3. Uncoiler Requirements

Minimum standards:

✔ Heavy-duty mandrel
✔ Hydraulic expansion
✔ Back tension control
✔ Coil car integration

Mandrel sizing must match coil ID (typically 508 mm standard).

Mandrel expansion tolerance critical for coil stability.

Maximum coil weight rating must exceed operational load by ≥25% safety margin.

4. Slitter Head Specification (Critical)

4.1 Arbor Diameter

Minimum arbor diameter:

Thickness Range	Minimum Arbor Ø
≤1.0 mm	120 mm
1.0–2.0 mm	150 mm
2.0–4.0 mm	200 mm

Undersized arbors increase knife deflection and edge burr.

4.2 Knife Material

Acceptable materials:

SKD11
D2
Equivalent hardened tool steel

Minimum hardness:

58–62 HRC

Knife parallelism tolerance:

≤0.01 mm

Improper knife quality leads to:

Edge burr
Camber
Strip distortion

5. Strip Tolerance Standards

Minimum tolerance benchmarks:

Strip width tolerance ±0.2 mm
Edge burr ≤10% of material thickness
Camber ≤2 mm over 2 meters
Coil edge wave within acceptable flatness

Poor slitting tolerances cause roll forming misalignment.

6. Drive System Requirements

6.1 Main Drive

Acceptable systems:

AC vector motor
Servo-controlled drive (preferred for precision lines)

Torque safety margin:

Minimum 30–40% above calculated load

6.2 Motor Sizing Benchmark

Thickness	Minimum Motor Power
≤1.0 mm	22–30 kW
1.0–2.0 mm	45–75 kW
2.0–4.0 mm	90–132 kW

Undersized motors cause strip tension instability.

7. Tension Control System

Mandatory components:

✔ Loop pit or dancer system
✔ Entry tension control
✔ Exit tension control
✔ Recoiler torque control

Tension inconsistency causes:

Coil telescoping
Strip camber
Edge wave

Tension precision must maintain ±5% consistency.

8. Recoiler Specification

Minimum standards:

Heavy-duty mandrel
Hydraulic expansion
Over-arm separator
Strip separator discs

Recoiler torque capacity must match slitting load with ≥25% safety margin.

Poor recoiling causes downstream feeding issues.

9. Production Speed Standards

Typical industrial slitting speeds:

Thickness	Speed Range
≤1.0 mm	80–150 m/min
1.0–2.0 mm	50–120 m/min
2.0–4.0 mm	30–80 m/min

Higher speed increases burr risk if knife setup is poor.

10. Electrical & Control Requirements

Industrial PLC mandatory.

Accepted systems:

Siemens
Allen Bradley
Equivalent industrial automation platform

System must include:

Strip width digital setup
Speed synchronisation
Tension monitoring
Production data logging

HMI must allow precision strip setup.

11. Safety Requirements

Minimum safety package:

✔ Full guarding
✔ Emergency stop circuits
✔ Light curtains
✔ Overload protection
✔ Strip break detection

High-speed coil processing presents serious operator risk.

12. Factory Acceptance Test (FAT) Requirements

Supplier must provide:

• Continuous slitting run at rated thickness
• Strip width measurement report
• Burr measurement report
• Tension stability validation
• Speed validation under load

Edited or segmented footage is unacceptable.

13. Underspecification Red Flags

Arbor diameter below 120 mm for light gauge
No tension control system
No burr tolerance declared
No width tolerance declared
Undersized recoiler torque
No documented FAT protocol

These significantly increase downstream roll forming instability.

14. Cost Exposure if Underspecified

Potential consequences:

Roll forming misalignment
Profile distortion
Coil rejection
Production downtime
Excess scrap
Knife replacement cost

Financial exposure can exceed $100,000–$1,000,000 annually in production loss.

15. Machine Matcher Compliance Checklist

A slitting line is compliant when:

✓ Arbor diameter meets thickness benchmark
✓ Knife hardness certified ≥58 HRC
✓ Strip width tolerance ±0.2 mm validated
✓ Tension control within ±5% stability
✓ Drive torque includes ≥30% safety margin
✓ Full-load FAT validation complete

Machines failing these thresholds introduce upstream production risk across all roll forming lines.