Vision inspection Troubleshooting: Causes & Fixes

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Problems on this page:

False rejects or missed defects Camera not triggering / no image Inconsistent results after changeover

False rejects or missed defects

Hits OEE: Quality

Symptoms: Good parts failed or bad parts passed, unstable inspection.

Lighting drift / ambient light

Stabilise and shroud lighting; re-baseline; lock exposure.

Lens/part fouling or focus

Clean optics; re-focus; secure the camera mount.

Thresholds/model not robust

Re-train or re-tune with current good/bad samples.

Prevention: Controlled lighting, optics cleaning, periodic model validation.

Camera not triggering / no image

Hits OEE: Availability

Symptoms: No inspection result or blank image; line stops or passes everything.

Trigger signal lost

Check the trigger sensor/encoder and wiring to the camera.

Power or comms fault

Verify camera power and the link to the controller.

Illuminator failed

Check the light/strobe and its trigger.

Prevention: Trigger and lighting checks, secure cabling.

Inconsistent results after changeover

Hits OEE: Quality

Symptoms: Inspection unstable after a product or format change.

Wrong program/recipe loaded

Confirm the correct recipe for the SKU.

Fixture or part position changed

Re-fixture to the taught position; check guides.

Lighting/focus not reset

Reset lighting and focus for the new product.

Prevention: Per-SKU recipes, changeover checklist, fixturing repeatability.

Vision inspection troubleshooting FAQ

Vision inspection: what causes false rejects or missed defects, and how do I fix it?

Symptoms: Good parts failed or bad parts passed, unstable inspection. Likely causes: Lighting drift / ambient light; Lens/part fouling or focus; Thresholds/model not robust. Fixes: Stabilise and shroud lighting; re-baseline; lock exposure. Clean optics; re-focus; secure the camera mount. Re-train or re-tune with current good/bad samples. Prevention: Controlled lighting, optics cleaning, periodic model validation.

Vision inspection: what causes camera not triggering / no image, and how do I fix it?

Symptoms: No inspection result or blank image; line stops or passes everything. Likely causes: Trigger signal lost; Power or comms fault; Illuminator failed. Fixes: Check the trigger sensor/encoder and wiring to the camera. Verify camera power and the link to the controller. Check the light/strobe and its trigger. Prevention: Trigger and lighting checks, secure cabling.

Vision inspection: what causes inconsistent results after changeover, and how do I fix it?

Symptoms: Inspection unstable after a product or format change. Likely causes: Wrong program/recipe loaded; Fixture or part position changed; Lighting/focus not reset. Fixes: Confirm the correct recipe for the SKU. Re-fixture to the taught position; check guides. Reset lighting and focus for the new product. Prevention: Per-SKU recipes, changeover checklist, fixturing repeatability.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Stop the same fault coming back

Recurring vision inspection stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: EU-built, so your production data stays in EU jurisdiction, with computer-vision true-cause of micro-stops, a closed loop from PLC-read OEE to an auto-routed work order, and ISO 27001 / 20000-1 / 9001 (supports audit-readiness).

See how Fabrico finds root cause

The directory stays free.

Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover