Shrink Wrapper Troubleshooting: Causes & Fixes

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Problems on this page:

Poor or open seals Film wrinkles or burn-through Infeed or case-erection jam Pack end openings too large or torn Film not fully shrunk Tunnel conveyor problems Wrong count in the bundle Long stops at film reel changes

Poor or open seals

Hits OEE: Quality

Symptoms: Bags open, weak seals, product loose in the pack.

Seal temperature or dwell wrong

Tune seal temperature and dwell for the film.

Worn seal wire, PTFE or element

Replace the seal wire, PTFE tape and element.

Film tension or tracking off

Set film tension and correct tracking.

Prevention: Seal element maintenance, validated settings per film, tension control.

Film wrinkles or burn-through

Hits OEE: Quality

Symptoms: Wrinkled or scorched film, holes, poor shrink appearance.

Tunnel temperature or airflow wrong

Tune tunnel temperature, airflow and conveyor speed.

Wrong film or gauge

Match film type and gauge to the product.

Uneven heat distribution

Check tunnel heaters and baffles.

Prevention: Validated tunnel settings, correct film, heater checks.

Infeed or case-erection jam

Hits OEE: Availability

Symptoms: Product backs up, cases not erected or glued, frequent stops.

Infeed metering fault

Check flighting, timing and infeed sensors.

Blank pick or glue fault

Check the vacuum pick and hot-melt glue system.

Product or blank variation

Tighten the incoming spec; adjust handling.

Prevention: Timing checks, vacuum and glue maintenance, blank and product QA.

Pack end openings too large or torn

Hits OEE: Quality

Symptoms: End openings (bullseyes) too big, too small or torn at the end of the shrink.

Film cut length or overlap wrong for the pack

Set film length and overlap for the pack size.

Uneven tunnel airflow at the ends

Adjust the tunnel baffles and air settings.

Film type or gauge not suited

Check film choice with the supplier for this pack.

Prevention: Film length settings recorded per pack size.

Film not fully shrunk

Hits OEE: Quality

Symptoms: Loose film, packs that do not hold together, film flapping.

Tunnel temperature or dwell too low

Set temperature and conveyor speed within the film's shrink window.

Blocked airflow in the tunnel

Clean tunnel filters and ducts.

Line speed raised without tunnel changes

Recheck tunnel settings whenever line speed changes.

Prevention: Tunnel settings tied to line speed on the format sheet.

Tunnel conveyor problems

Hits OEE: Availability

Symptoms: Packs marked or stuck on the tunnel conveyor, belt wandering, rollers not turning.

Worn or damaged mesh belt

Repair or replace the tunnel belt.

Rollers seized from heat

Replace seized rollers and their bearings.

Film sticking to the belt

Check belt type and cooling at the tunnel exit.

Prevention: Tunnel conveyor inspection during planned maintenance.

Wrong count in the bundle

Hits OEE: Quality

Symptoms: Bundles with a missing or extra unit, mixed patterns.

Infeed lane control unstable

Check lane guides and the metering at the infeed.

Pusher or flight timing drift

Re-time the pushers or flights.

Products tipping in the group

Add support guides and soften accelerations.

Prevention: Count checks at start-up and after changeover.

Long stops at film reel changes

Hits OEE: Availability

Symptoms: Every reel change stops the wrapper for a long time; threading mistakes.

No prepared splice

Prepare the next reel and splice before the reel runs out.

Threading path unclear

Post a threading diagram at the unwind and write the method down.

Reel size or core not as agreed

Agree reel size and core with the film supplier.

Prevention: Reel changes treated like a changeover and practised.

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

Related equipment guides: stretch wrapper · slitter rewinder · packaging line · filling machine · sleeve labeller · tray former · tissue converting line

Stop the same fault coming back

Recurring shrink wrapper 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