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Composite manufacturing

X-ray defect detection on carbon-fibre structural parts

An anomaly-ranking workflow and human review station were evaluated on multi-machine X-ray images.

DELAMINATIONFLAGGED · NGRISK QUEUErank 1 · NGVision ranks the riskiest image first; people confirm.
Background

The manufacturer produces carbon-fibre structural parts for performance brands. Every part is X-rayed and a trained inspector decides pass or fail. As volume grew across two factories and several X-ray machines, that manual step became the bottleneck and the source of the most expensive escapes.

Judgement varied by inspector and by shift, the hardest defect (delamination) was easy to miss, and images came from machines with different characteristics, so no single rule of thumb held across the line.

Business challenges

Manual review could not keep up

Every scan waited for a person, and throughput dropped whenever an experienced inspector was off.

The costly defect was the easiest to miss

Delamination is subtle on an X-ray, and it is exactly the defect customers care about most.

Several machines, different images

An older CT and newer scanners produced different image profiles, so a model tuned on one did not transfer.

No labelled OK / NG history

There was no clean dataset to train a classic supervised model from day one.

Solution

We started unsupervised. An anomaly model ranks every image by how unusual it looks, rolled up to the part by barcode, so inspectors review the riskiest images first instead of all of them. Each machine gets its own calibration, and same-machine comparisons are kept separate from cross-machine ones.

A review workstation lets inspectors confirm or overturn the ranking, and those labels feed a growing hard-case library. The system never auto-promotes a model or hides uncertainty: when it does not have the data, it says so.

Scope
Rapid design & deployment

One expensive problem, proven before it scales. The A1 to POC method, run in weeks not quarters.

A1 · Confirm the goal
Pin the one defect and the pass mark, agreed with QE before any model.
A2 · Audit the data
Map machines, image profiles, and what labels actually exist.
A3 · Design the use case
Choose ranking over classification, and decide who reviews what.
POC · Build & evaluate
Train and tune by machine; clean held-out validation remains the next gate.
Evaluation · Review workstation
Evaluate the workstation, label flow, and named human owner in a bounded setting.
Governance & standards

Our delivery practices define human decision ownership, source and output traceability, data boundaries, change control and review evidence.

Personal credential
Vincent Lin · PECB Certified ISO/IEC 42001 Lead Implementer

The credential is held personally by Vincent Lin.

Related use cases
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