Process control
Engineering Question
What does a burr-height requirement tell you about a cut CRGO lamination?
Key Data
- Chenfan burr-height control: <0.02 mm.
- Burr height is one edge-quality measurement; it is not a finished-core loss guarantee.
Technical Explanation
A burr is raised metal at a cut edge. Excessive burrs can interfere with stacking and, under contact pressure, damage insulation between laminations. Electrical contact between sheets can provide additional current paths and contribute to local heating or loss.
A burr creates an additional eddy-current path only when conductive contacts form a closed loop that links changing magnetic flux.
The risk depends on the edge condition, coating, alignment and assembly pressure. The specified limit is a manufacturing control value, not a universal boundary below which insulation damage is impossible. Visual appearance or a smooth feel cannot establish magnetic performance.
Tool wear, cutting clearance and material condition influence the edge produced by slitting and cross-cutting. A useful inspection plan defines where to measure, how samples represent the batch, which instrument is used and what action follows an out-of-limit result. A measured value needs that context to be comparable.
Cutting can also introduce local mechanical stress without producing an obviously large burr. Edge inspection should therefore sit alongside dimensional checks, coating inspection and any agreed magnetic verification.
Engineering Implications
- Inspect representative cut edges and changes associated with tool condition.
- Control handling and clamping so acceptable laminations remain protected during assembly.
Procurement Implications
- Include the burr requirement and its inspection basis in the technical agreement.
- Avoid treating a single edge reading as evidence that an entire core meets its loss limit.
What to Confirm Before Ordering
- Material grade, thickness and coating specification.
- Measurement method, sampling positions and reporting requirement.
- Batch traceability and the agreed response to nonconforming laminations.
For production enquiries, review the CRGO lamination supply specification and the wider transformer core manufacturing scope. State the inspection method with the requirement rather than treating burr height alone as a loss guarantee.