Blown Film Bubble Stability and Gauge Band Check

Per-shift inspection for blown film lines to verify bubble stability, frost line height, gauge band presence, and thickness variation before off-spec rolls are produced.

Inspection Details

• Line or machine identified
• Shift and date recorded
• Product grade or resin lot recorded
• Inspector name recorded

Bubble Stability

• Bubble is stable with no visible oscillation
• No signs of bubble flutter, surging, or wandering
• Air ring, cooling, and draft conditions appear consistent
• Any unusual noise, vibration, or instability observed

Frost Line Height and Process Control

• Frost line height within target range
• Frost line is uniform and not visibly fluctuating
• Cooling air and ambient drafts are not affecting the bubble
• Process adjustments made during this shift

Gauge Bands and Thickness Variation

• No visible gauge bands on film web or roll
• Thickness variation is within specification
• No scratches, tears, wrinkles, or edge defects linked to instability
• Defect location and roll number recorded if a band or variation was found

Corrective Actions and Closeout

• Corrective action taken or escalation initiated
• Affected rolls placed on hold or identified for review
• Inspector sign-off completed