Zero defect at the box-build station
Payback 5-12 months · from sampling to 100% control
Box-build is the last station and the least inspected.
That unit reaches the OEM customer and turns into a return, a quality claim, or in the worst case a field investigation.
- Final assembly is manual by nature: connectors seated by hand, screws torqued, harnesses routed, labels applied, enclosure closed. It is where board work turns into a product.
- And it is inspected by sampling, typically 1 to 5 % of units, because inspecting every unit by eye at cadence is not realistic and nobody pretends otherwise.
- So a connector that looks seated but is not, a missing screw on a panel, or a label applied to the wrong face leaves the plant inside a sealed box, and the enclosure makes the defect unreachable from that point on.
- That unit reaches the OEM customer and becomes a return, a quality claim, or in the worst case a field investigation on a program you assemble for several customers at once. In an EMS business the claim costs more than the unit ever did, because what it really costs is scorecard and the next award.
Edge — a camera over the station and a model trained on that program's own product.
Edge: an industrial camera over the final assembly station + a CNN trained on good/bad examples of each program's specific product. Millisecond inference, no image sent to the cloud. The defective unit is stopped before packaging.
Inference happens in milliseconds on the station itself: no image leaves the plant, which is what makes the case approvable when the product belongs to somebody else's brand. The defective unit is stopped before packaging, not after shipping — and the operator gets the signal at their own bench, while the unit is still open in front of them.
Today's final inspection versus Edge vision
| Aspect | Sampling inspection | With iLEAN Edge |
|---|---|---|
| Coverage | 1-5 % of units | 100 % unit control |
| Unseated connector | Looks fine to the eye | Classified unit by unit |
| Missing screw or label | Caught if it is in the sample | Caught before packaging |
| Where the defect is found | At the OEM customer | At the station |
| Customer claims over visual defects | Recurring | Drastically reduced |
| Images of the customer's product | — | Never leave the plant |
1-5% sampling → 100% unit control. Customer claims over visual defects → drastic reduction.
Impact estimate — to be validated with your numbers.
The block below is an estimate to be validated against your plant's actual data. We put it forward so the committee has an order of magnitude; we refine it during the assessment.
- Estimated payback 5-12 months, depending on your volume and your current claim rate.
- From 1-5 % sampling to 100 % unit control on the covered product families.
- Customer claims over visual defects drastically reduced — and in an EMS plant a claim costs far more than the unit, because what it really costs is position on the customer's supplier scorecard.
- And the defective unit is stopped before packaging, which removes return freight, rework at the customer's site and the credit note that follows — along with the corrective action report somebody would have had to write.
Payback 5-12 months · from sampling to 100% control. Estimate to be validated.
And the fair question from the production manager
“What if it rejects good units?” — the false positive is the real risk of any vision system, which is why the model is trained on good and bad examples of that specific program's product and under that station's lighting, not on a generic model. Classifying against trained references is an anchored task where the best models drop below 1.5% error [1], and borderline units are escalated to the operator rather than rejected outright.
[1] OpenAI paper "Why Language Models Hallucinate", 2025 — on the reliability of AI in anchored tasks.
What people ask about vision at box-build
Does it keep up with the station's cadence?
Yes. Inference is local and resolves in milliseconds per unit, so it does not depend on the plant network or on any cloud service being available, and a network outage does not stop the line.
How many units are needed to train it?
Fewer than people expect, because the defect catalog at box-build is short and repetitive: the same connector, the same screw positions, the same label. What matters is that they are real units from that program, photographed at that bench.
What happens when the program changes?
The model switches with the active work order, the same way the inspection program does. High customer mix is the assumption behind the whole design, not an exception to be handled later.
Do images of our customers' products leave the plant?
No. Inference runs on the station itself and no image is sent outside. That is usually the condition an OEM's own quality team sets before approving the case, and it is met by design rather than by policy.
Does it replace functional test?
No. Functional test stays the electrical reference and should. Edge covers what functional test cannot see: a screw that is not there, a label on the wrong face, an enclosure that closed over a pinched harness.
More cases from this series
- The AOI that never drifts from the work orderThe AOI machine gets stitched to the MES via API: the right inspection program activates automatically…
- Component shortage alert in zero secondsiLEAN silently reads a supplier's shortage alert and returns the concrete replanning action.
- Photo the kit traveler at batch startHow an EMS plant digitizes the kitting traveler with a photo: the work order exists in the system at…
- The line lead who dictates hands-freeThe line lead dictates incidents while walking the SMT floor; iLEAN structures them and replies in…
- The quality spreadsheet that flows to the ERP on its owniLEAN watches the quality lab folder and pushes data to the ERP after validation, saving licenses.
- Photo the packing slip, reels to the ERPOne photo of the packing slip and reel labels is enough to push component receiving into the ERP.
Tell us what proportion of your customer claims are visual defects at box-build.
We work on your plant's real data, not ours. Assessment with no commitment.
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