Shop-Floor Defect Atlas & Troubleshooting Matrix

Tyre Building

Visual Symptoms Trapped pockets of air between the innerliner and the first carcass ply during first-stage building.

Root Causes Insufficient stitcher roller pressure, high line speed, or uneven drum profile expansion.

Corrective Actions Increase stitcher force, use grooved stitching rollers, and apply vacuum assisted building tables if available.

Calendering

Visual Symptoms The edges of the rubber sheet or liner wave and buckle due to different material flow velocities across width.

Root Causes Incorrect differential speed (friction ratio) between calendar rolls or localized overheating of roll ends.

Corrective Actions Adjust friction gear ratios, calibrate roll temperature cooling zones, and check material feed tension.

Curing

Visual Symptoms Incomplete rubber flow into the upper or lower shoulder areas of the tyre mold pattern.

Root Causes Low green tyre weight, low pre-shape bladder pressure, or cold mold sections.

Corrective Actions Check green mass scale limits, increase initial bladder shaping pressure, and inspect platen steam traps.

Calendering

Visual Symptoms Portions of the textile cord fabric remain uncovered by rubber compound after passing through calendar nip.

Root Causes Low rubber bank size on calendar rolls, incorrect roll gap settings, or uneven let-off alignment.

Corrective Actions Maintain a consistent, uniform rubber bank size across the roll width and verify nip gap calibration.

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