Tray Sealer Troubleshooting: Causes & Fixes

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Problems on this page:

Leaking tray seals High residual oxygen in MAP packs Film wrinkles or misaligned lidding Film not cut cleanly around the tray Trays jamming at the infeed or tool Vacuum pump faults Slow tool changes Gas use higher than expected

Leaking tray seals

Hits OEE: Quality

Symptoms: Leak-test rejects rise, packs blow or weep in distribution, seals peel at a corner.

Contaminated seal flange

Fix product loading so sauce or fines stay off the flange; add flange cleaning or adjust fill levels.

Seal tool temperature or pressure off

Verify platen temperature, pressure and dwell against the film and tray spec; check heater zones for cold spots.

Tray or film lot variation

Audit incoming trays for warp and flange quality; qualify film lots before committing a shift.

Prevention: Leak testing per batch, seal tool temperature mapping, flange contamination audits, incoming tray checks.

High residual oxygen in MAP packs

Hits OEE: Quality

Symptoms: Gas analyser rejects, shelf-life complaints, O2 creeping up across the shift.

Insufficient vacuum or gas flush time

Verify the vacuum level and gas flush settings against the validated recipe; do not trade cycle time for residual O2.

Gas supply problems

Check gas mix, supply pressure and blocked nozzles; confirm the mix at the tool, not just at the manifold.

Chamber or tool leaks

Test chamber gaskets and fittings; a small chamber leak pulls air back in before sealing.

Prevention: Gas analysis per batch with trending, chamber gasket PM, gas supply checks at startup.

Film wrinkles or misaligned lidding

Hits OEE: Quality

Symptoms: Wrinkled lids across the seal area, print off-centre, film tears at the grippers.

Film tension or tracking off

Adjust unwind tension and web guides; verify the film width matches the tool.

Worn film grippers or transport

Replace worn gripper chains and check they pull evenly on both sides.

Tool alignment

Check seal tool alignment to the tray pockets after any crash or tool swap.

Prevention: Film tracking checks at changeover, gripper wear PM, tool alignment verification after crashes.

Film not cut cleanly around the tray

Hits OEE: Quality

Symptoms: Ragged film edges, film tails, trays joined by film.

Dull or damaged cutting knives

Replace or sharpen the knives.

Knife alignment off

Align the cutting tool as the OEM describes.

Film not suited to the cut

Check film type with the supplier.

Prevention: Knife inspection at every tool change.

Trays jamming at the infeed or tool

Hits OEE: Availability

Symptoms: Trays caught entering the tool, crushed trays, stops.

Tray dimensions vary

Check tray dimensions against spec with the supplier.

Trays placed off position

Set infeed guides and pitch.

Denester faults

Adjust the denester for the tray.

Prevention: Tray checks at receiving and infeed settings per tray.

Vacuum pump faults

Hits OEE: Availability

Symptoms: Slow cycles, vacuum not reached alarms, oil mist.

Oil level or condition

Check and change oil as the pump maker says.

Blocked filters

Replace inlet and exhaust filters.

Leaks in lines or seals

Find and fix leaks in vacuum lines and chamber seals.

Prevention: Pump service on a schedule.

Slow tool changes

Hits OEE: Availability

Symptoms: Changing tray format takes long and the first packs leak.

Heavy tools without a trolley

Use a tool trolley at the right height.

Couplings and connections slow to fit

Use quick couplings for gas and water where the OEM allows.

No written method

Write and practise the tool change.

Prevention: Tool change treated as a changeover project.

Gas use higher than expected

Hits OEE: Performance

Symptoms: Gas consumption rises without a change in output.

Leaks in gas lines or fittings

Leak test the gas lines and fittings.

Flush time set longer than needed

Validate flush time with a headspace analyser.

Worn chamber seals

Replace chamber seals.

Prevention: Leak checks and headspace checks on a schedule.

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 tray sealer 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.

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