Slitting Lines for Electrical Steel & Laminations
Electrical steel is the only material where slitting quality is measured in watts. Burrs on CRGO or CRNO strip short adjacent laminations and raise core losses; cutting stress degrades the magnetic properties the material was bought for. Transformer and motor makers pay premium prices for low-loss grades — and bad slitting silently gives those losses back.
Friend Engineering Works builds slitting lines for the lamination industry: transformer core strip, motor stamping strip and toroidal core material, configured for burr-free edges and coating-safe handling of insulated silicon steels.
Electrical Steel Slitting Requirements
- Minimal burr: burr height on lamination strip is specified in hundredths of a millimetre — it determines stacking factor and interlaminar shorts
- Coating preservation: CRGO/CRNO insulation coatings must survive processing — covered rolls and clean strip paths throughout
- Low-stress cutting: sharp knives and correct clearance limit the stress-affected zone at the cut edge that degrades magnetic performance
- Camber control: lamination stampers running progressive dies need camber-free strip for consistent feed
Materials & Applications
| Material | Application | Notes |
|---|---|---|
| CRGO 0.23–0.35mm | Transformer cores | Grain-oriented; burr and stress critical |
| CRNO 0.35–0.65mm | Motor & generator laminations | Non-oriented; high-volume stamping strip |
| Aluminium/copper strip | Windings | See our non-ferrous configurations |
Why Burr Height Rules This Industry
A stacked core with burred laminations has two problems: lower stacking factor (air gaps between sheets) and interlaminar shorts where burrs pierce insulation coating — both raise core losses directly. Our lamination-duty slitter heads are built and maintained around burr specification first; everything else follows from it.
Recommended Equipment
- Slitting Line — Friend Engineering Works slitting lines are designed to ensure the highest standards of quality and productivity while processing different materials.
- Recoiler Machine — Our recoiler machines provide consistent tension control for rewinding processed metal strips.
- Decoiler Machine — Our decoiler machines are designed for efficient and safe uncoiling operations with heavy-duty construction.
Frequently Asked Questions
What burr height is acceptable when slitting CRGO?
Transformer manufacturers typically specify burr below 0.02–0.03mm on CRGO strip. Achieving it consistently requires precision-ground knives, exact clearance for the gauge, and disciplined knife maintenance — our lamination-duty lines are specified and test-run against your burr requirement.
Does slitting affect the magnetic properties of electrical steel?
Yes — cutting introduces stress at the edge that locally degrades permeability and raises losses. The effect is minimized with sharp knives at correct clearance, and it is one reason lamination producers keep dedicated, well-maintained lines for silicon steel rather than sharing a general-purpose slitter.
Can you slit coated (insulated) electrical steel without damaging the coating?
Yes. C-coating classes on CRGO/CRNO survive processing on lines with covered contact rolls, clean strip paths and correct tension. The knife area is the only place the coating is intentionally interrupted — everywhere else the line is configured not to touch it aggressively.