X-ray Inspection Troubleshooting: Causes & Fixes

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Problems on this page:

False rejects Test pieces not detected Rejected product not removed X-ray generator will not start Cabinet overheating Belt tracking or product position problems Curtains or guards stopping the line Noisy or unclear image

False rejects

Hits OEE: Quality

Symptoms: Good product is rejected, and rejected packs show nothing wrong when checked.

Product density varies more than the setup expects

Relearn the product with a representative sample.

Product overlapping or clumped in the pack

Improve spacing or orientation upstream.

Sensitivity set tighter than needed

Set the sensitivity to the contaminant sizes your HACCP plan requires.

Wrong product setup selected

Link the setup to the product changeover.

Prevention: False reject rate tracked per product so a change is noticed.

Test pieces not detected

Hits OEE: Quality

Symptoms: The routine check with test pieces fails, or a test piece passes through.

Product setup not suited to the pack

Relearn the product and repeat the test.

Detector or tube performance has dropped

Run the maker diagnostic and call service if it fails.

Test piece in a position the setup cannot see

Test in the positions your validation defines.

Belt speed changed

Check the speed against the setup.

Prevention: Test piece checks at the frequency your food safety plan sets, recorded each time.

Rejected product not removed

Hits OEE: Quality

Symptoms: The system signals a reject but the pack carries on down the line.

Reject device timing wrong

Set the timing for the belt speed and pack length.

Low air pressure to the reject device

Check the air supply and the pressure switch.

Reject bin full

Fit a bin full sensor that stops the line.

Reject device worn or blocked

Check the pusher or air blast nozzle.

Prevention: Reject confirmation checked as part of every test piece check.

X-ray generator will not start

Hits OEE: Availability

Symptoms: The system stays in standby with a generator or tube fault.

Interlock or curtain fault

Check the guards and interlock circuit.

Cooling fault on the generator

Check the cabinet cooling and filters.

Tube at end of life

Call the service partner; only trained, authorised staff work on the generator.

Prevention: A service contract that includes generator checks.

Cabinet overheating

Hits OEE: Availability

Symptoms: The system stops on a temperature alarm.

Cabinet cooler or air conditioner fault

Check and service the cabinet cooling unit.

Filters blocked

Clean the cooling filters.

Hot or washdown environment

Check the unit rating against the room and the cleaning regime.

Prevention: Cooling filters on the monthly PM.

Belt tracking or product position problems

Hits OEE: Quality

Symptoms: Packs drift to the edge of the belt or turn as they pass the detector.

Belt tracking out of adjustment

Track the belt and check the rollers.

Infeed transfer uneven

Align the infeed conveyor and its speed.

Worn belt

Replace the belt.

Prevention: Belt condition on the weekly round.

Curtains or guards stopping the line

Hits OEE: Availability

Symptoms: The system stops on an interlock fault during production.

Curtains worn or missing strips

Replace the shielding curtains with the parts the maker specifies.

Guard switch loose

Fix the switch and its actuator.

Product catching on the curtains

Check the pack height against the tunnel and curtain settings.

Prevention: Curtain condition checked daily before production.

Noisy or unclear image

Hits OEE: Quality

Symptoms: The image is grainy or streaked and detection becomes unreliable.

Detector dirty or damaged

Clean the detector window as the maker describes.

Belt dirty or marked

Clean or replace the belt.

Generator settings drifted

Run the calibration routine.

Prevention: Calibration run at the interval the maker sets.

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

Related equipment guides: metal detector · checkweigher · vision inspection · packaging line · AOI machine · optical sorter

Stop the same fault coming back

Recurring X-ray inspection stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.

Book a Fabrico demo

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