Flow Wrapper Troubleshooting: Causes & Fixes

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Problems on this page:

Print registration drifting off the eye mark Weak or burnt end seals Product jams at the infeed chain Leaking or weak fin seals Film wandering or tracking off Product caught in the end seal Film breaks Packs not cut cleanly

Print registration drifting off the eye mark

Hits OEE: Quality

Symptoms: Graphics wander along the pack, cut lands mid-print, waste film piles up at restarts.

Eye-mark sensor dirty or misaligned

Clean the registration sensor, re-teach on the actual film lot and verify mark contrast; a misread mark walks the cutoff.

Film slipping at the draw rollers

Check draw roller pressure and wear; dusty or waxy films need cleaning cadence on the rollers.

Unwind tension unstable

Service the unwind brake or dancer so tension stays constant as the roll diameter falls.

Prevention: Sensor cleaning cadence, re-teach at every film lot change, draw roller wear checks, unwind tension verification in PM.

Weak or burnt end seals

Hits OEE: Quality

Symptoms: Packs open at the crimp, channel leaks at the corners, dark scorched seals on slowdowns.

Crimper temperature wrong for the speed

Match sealing temperature to line speed and film spec; fixed heat that is right at full speed burns seals at crawl.

Worn or dirty crimper jaws

Clean product residue from the knurls and re-cut or replace worn jaws; damaged knurls leave unfused channels.

Film or gusset misfolded at the seal

Check forming box setup and product height so extra film layers do not enter the crimp.

Prevention: Seal integrity checks each shift (squeeze or dye test), jaw cleaning cadence, temperature-speed recipe per film.

Product jams at the infeed chain

Hits OEE: Availability

Symptoms: Products tip or double up at the lugs, wrapper stops on product-in-seal faults, crushed product in the film tube.

Infeed timing off vs product pitch

Re-time the infeed so product centres between lugs; check the product-in-place sensor position.

Irregular product size or shape

Tighten upstream size control; oversize product strikes the forming box and jams.

Worn lugs or guides

Replace bent lugs and worn side guides that let product skew before the tube.

Prevention: Infeed timing check at changeover, upstream product size audits, lug and guide inspection in PM.

Leaking or weak fin seals

Hits OEE: Quality

Symptoms: Packs leak along the long seal, or lose their gas flush.

Fin seal temperature or pressure wrong for the film

Set fin seal temperature and pressure to the film maker's guidance.

Worn or dirty fin wheels

Clean or replace the fin wheels.

Film running off-centre

Centre the film and adjust the former.

Product in the seal area

Keep product and crumbs away from the fin seal path.

Prevention: Seal integrity checks at start-up and after every film change.

Film wandering or tracking off

Hits OEE: Quality

Symptoms: Fin seal off-centre, print uneven from pack to pack, film riding off the former.

Reel not centred on the unwind

Centre the reel on the shaft.

Misaligned rollers or dancer

Align the rollers and check the dancer arm moves freely.

Uneven film tension

Set the unwind brake and tension.

Poorly wound reels

Reject telescoped or badly wound reels.

Prevention: Roller alignment checks and reel inspection at receiving.

Product caught in the end seal

Hits OEE: Quality

Symptoms: Product trapped in the cross seal, leaking packs, cut product.

Product pitch out of time with the jaws

Re-time the infeed flights to the jaw cycle and use product-in-seal detection where fitted.

Product length varies too much

Set and control the product length tolerance upstream.

Jaw dwell or profile wrong for the speed

Adjust jaw dwell, or use the jaw motion profile the OEM gives for the speed.

Prevention: Infeed timing checks at every format change.

Film breaks

Hits OEE: Availability

Symptoms: Film snaps at the unwind, a splice or the forming box, with a long restart each time.

Too much or jerky unwind tension

Check the brake and dancer for smooth tension.

Weak splices

Use one standard splice method and splice tape.

Damaged film edges

Handle reels carefully and inspect edges before loading.

Sharp edges on the former or guides

Inspect and smooth any burrs on the former and guides.

Prevention: Standard splicing and a reel handling routine.

Packs not cut cleanly

Hits OEE: Quality

Symptoms: Packs joined together, ragged or torn cut edges.

Dull or damaged knife

Replace or sharpen the knife.

Knife timing off against the jaws

Re-time the knife to the jaws.

Jaw pressure too low

Set jaw pressure to spec.

Prevention: Knife changes on a schedule and a cut check at start-up.

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 flow 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.

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