CATENARY · CONVEYOR FIELD GUIDANCE

Conveyor belt splice defects: causes, checks and remedies

Splicing · Technician

Most splice failures come from the way the splice was made, not from the belt design. Match what you see to the likely cause, confirm it with a field check, and fix the cause before remaking the splice.

Safety first: observe a running conveyor only from designated guarded positions. Isolate, lock out and verify zero energy, and secure take-up movement, before any hands-on check or correction.

Blisters or cover blows

Likely causes: cement not dry or applied too thick, trapped air, moisture on the surfaces, or the press opened while hot. Check the cure log release temperature and the dew-point record. Remedy: cut out and remake the area; enforce the tack test, the dew-point gate and cooling under pressure.

Splice opening or ply separation at the steps

Likely causes: plies nicked during stripping, fabric buffed through, expired materials, under-cure, steps shorter than the maker's, pulleys below the minimum diameter, or excess tension. Check step lengths against the maker and pulley diameters against the belt maker's minimum. Remedy: correct the pulley or tension cause first, then remake the splice.

Fill strip breaking up

One manual names fill-strip breakdown as a leading cause of early fabric-splice failure. Check for a straight-edge imprint and scraper contact on the fill. Remedy: correct the fill thickness and buff it to belt gauge.

The same belt section tracks off all the way round

A belt section that drifts wherever it is on the conveyor points to a splice that is not square or straight. Check straightness and squareness (Splice QA checks tab). Remedy: remake the splice from a corrected centre line; training idlers will not cure it.

The belt always tracks off at the same place

If drift happens at one fixed point of the structure, the cause is the structure, idlers or loading, not the splice. Use the belt mistracking guide and correct alignment only under isolation.

Steel cord splice too thin, porous or bulging

A light or porous splice is under-built; a bulging one is over-built. Measure thickness at both edges and the centre against the belt. Remedy: remake to the maker's material quantities and edge-bar setting.

Cord corrosion near the splice

Likely causes: moisture entry, nail or fastener holes, or chlorinated solvent used on the cords. Check visually and with the belt scanning or NDT records if available. Remedy: repair as the belt maker specifies and remove the moisture path.

Cuts or cracks next to a mechanical splice

The fastener is too small for the pulley it passes over, or not rated for the tension. Check the fastener maker's minimum pulley and rating against the smallest pulley and T1 (Mechanical fastener check tab). Remedy: a larger fastener size, a larger pulley, or a vulcanised splice.

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Source note: Causes summarised from ContiTech fabric splice manual (2015), Mercurio manual REV.08/22, Sempertrans V a/12.2020, Fenner Dunlop steelcord procedure v10.4 and Nordell (1993). Original wording; isolate and lock out before any inspection by hand.. Field guidance supports your judgment. Site procedures, manufacturer instructions and current standards govern final decisions.