Pallet Labeller Troubleshooting: Causes & Fixes

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Problems on this page:

Labels not applied or falling off Barcode unreadable by the customer Wrong label on a pallet Label missing on the second face Applicator arm or tamp faults Printer ribbon problems Label data not received from the warehouse system Safety guarding problems

Labels not applied or falling off

Hits OEE: Quality

Symptoms: Pallets leave the labeller without a label, or labels peel off in the warehouse.

Label adhesive not suited to the stretch film or temperature

Check the label stock with the supplier for the film and storage temperature.

Applicator pad or tamp not reaching the pallet

Check the tamp stroke and the pallet position sensor.

Pallet stopping in the wrong place

Check the conveyor stop sensor and the pallet position.

Label reel empty or web broken

Check the label reel and set a low-label warning.

Prevention: Label presence checked by scanner or on each pallet at the dispatch check.

Barcode unreadable by the customer

Hits OEE: Quality

Symptoms: Customers or the warehouse cannot scan the pallet label.

Print darkness or speed wrong

Check the printer settings for the label and ribbon.

Print head dirty or worn

Clean the print head and replace it if lines are missing.

Label applied over a film overlap or crease

Check the label position on the pallet.

Code not verified after printing

Use a verification scanner and check its grades.

Prevention: Codes verified on samples each shift.

Wrong label on a pallet

Hits OEE: Quality

Symptoms: A pallet carries a label with the wrong product, batch or quantity.

Label data sent before the pallet arrived

Check the sequence between the palletiser and the labeller data.

Pallet removed from the line by hand

Record manual removals so the label sequence stays correct.

Batch data not updated at a changeover

Check the batch data at every changeover.

Two pallets too close together

Check spacing on the conveyor.

Prevention: Pallet labels compared with the pallet contents on samples.

Label missing on the second face

Hits OEE: Quality

Symptoms: Pallets that need labels on two faces leave with only one.

Second applicator or pallet turn not running

Check the second applicator or the turntable that presents the second face.

Pallet position sensor for the second face faulty

Clean and test the sensor.

Timing between the two applications wrong

Check the timing set for the pallet size.

Program set for one-face labelling

Check the label program for the customer requirement.

Prevention: Both faces checked at the dispatch check.

Applicator arm or tamp faults

Hits OEE: Availability

Symptoms: The applicator arm stalls, misses the pallet or drops labels.

Air pressure low at the applicator

Check the air supply and regulator at the labeller.

Vacuum on the tamp pad weak, so the label drops

Check the vacuum generator and clean the pad holes.

Cylinder seals worn

Replace the seals of the slow or leaking cylinder.

End position sensors misaligned

Align the arm position sensors.

Prevention: Applicator faults logged by type.

Printer ribbon problems

Hits OEE: Availability

Symptoms: The thermal transfer ribbon wrinkles, breaks or leaves gaps in the print.

Ribbon tension wrong

Set the ribbon tension as the printer maker specifies.

Ribbon type not matched to the label

Use the ribbon grade recommended for the label stock.

Print head pressure uneven

Adjust the head pressure across the label width.

Ribbon path misthreaded

Rethread the ribbon following the path diagram.

Prevention: Ribbon changes and breaks recorded.

Label data not received from the warehouse system

Hits OEE: Availability

Symptoms: The labeller waits for data, and pallets queue on the conveyor.

Network link down

Check the network connection and switch port.

Data format changed in the warehouse system

Check the label template against the data fields sent.

Print queue stuck

Clear the queue and find the message that blocked it.

Label server down

Check the label server status with IT.

Prevention: Data errors logged with time and pallet number.

Safety guarding problems

Hits OEE: Availability

Symptoms: The labeller stops on light curtain or guard faults.

Light curtain misaligned or dirty

Clean and align the light curtain.

Guard door switch out of adjustment

Adjust the switch so it proves the door is closed.

Muting sensors not seeing the pallet

Check the muting sensors and their timing.

Safety device bypassed

Remove any bypass and find why it was fitted; the applicator arm can strike people.

Prevention: Guards and light curtains tested daily.

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

Related equipment guides: palletizer · stretch wrapper · print and apply labeller · barcode scanner · conveyor

Stop the same fault coming back

Recurring pallet labeller 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