The fastest safe troubleshooting method follows the weft from package to receiving side. Record what changed, inspect the physical path, and correct the root cause before raising pressure or changing several timings at once.
OBSERVE FIRST
Use position and yarn shape as evidence
Identify whether the failure occurs near the feeder, main-nozzle side, middle of the reed space or receiving side. Check whether the weft is broken, looped, curled, short, slack or present but undetected. The pattern narrows the inspection and helps prevent unnecessary adjustments.
INSERTION CAUSES
Check yarn, air and timing in process order
Possible causes include a poor package, yarn weakness or twist liveliness, rough guides, unstable feeder tension, stopper or cutter problems, air leakage, misaligned nozzles, weak relay handover, reed contamination, unclear shedding or incorrect release and arrival timing.
- Package and feeder: withdrawal, storage and release
- Air system: supply under load, leakage and valve response
- Guided path: nozzle alignment, profiled reed and shed clearance
- Arrival: detector cleanliness, position, sensitivity and signal
DEFECT LOCATION
Relate the cloth mark to the responsible zone
A defect near the insertion side may point toward release, main-nozzle duration, cutting or excess slack. A receiving-side defect can indicate insufficient final transport, rebound, selvedge handling or detection. Full-width weft contraction can involve air continuity, shed obstruction, yarn behavior or reed condition. Double picks or missing picks also require detector and restart-procedure checks.
CORRECT AND CONFIRM
Return to stable production with one verified change
Clean and inspect before changing the recipe. Repair leakage, roughness, alignment, yarn-path or sensor problems first. Then make a limited process adjustment and confirm it through several production cycles, fabric inspection and the stop log.
Send evidence, not only the alarm name
Clear photos, the stop location, yarn and fabric data, alarm history and current settings help JETMECH provide a more useful technical response.