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.