Why your conveyor belt splice joints are easy to open ?

The main causes of cracking at conveyor belt splice joints can be summarized into the following three aspects:

I. Insufficient Splice Strength This is the fundamental reason for splice cracking

Regardless of the connection method used, the strength at the splice joint is lower than that of the main belt body. Different splicing techniques exhibit significant differences in joint strength

Mechanical Fastening: This method provides the lowest splice strength, typically only 40%-50% of the belt body's strength

Cold Bonding: With good workmanship, the splice strength can reach 60%-70% of the belt body's strength

Hot Vulcanization: This is the most reliable connection method. When performed correctly and without quality defects, the splice strength can reach a maximum of 80-90% of the belt body's strength

II. Defects in Splice Manufacturing Process Incorrect bonding methods can further weaken the joint strength, making it more prone to cracking during use. Common process issues include:

Operational Damage: During cutting or grinding, if the fabric or steel cord of the underlying layer is damaged, or if over-grinding occurs, the integrity of the reinforcement material is directly compromised.

Improper Structural Design: Insufficient overlap length or an insufficient number of steps reduces the effective bonding area, preventing the joint from withstanding normal working tension.

Material Problems: Using bonding rubber with poor performance, or rubber that has self-vulcanized and become ineffective due to improper storage, leads to a decrease in adhesive strength. For steel cord belts, over-grinding or rusting of the steel cords also severely affects joint strength.

Process Omissions or Errors: Failure to use sealing gum during splice fabrication, or an incorrect splice direction (not aligned with the belt's running direction), can easily cause cracking at the joint, especially in the cover rubber area.

III. Operational and External Factors Beyond issues with the splice itself, improper daily operation and external environmental factors can also induce or accelerate joint cracking:

Frequent Start-Stop Cycles and Instantaneous High Tension: Conveyors with short duty cycles and frequent starts subject the splice to significant instantaneous tension, making it prone to tearing.

Equipment Design Issues: If the diameter of the bend pulley is too small, excessive bending stress occurs when the belt wraps around it, causing damage to the splice area.

External Mechanical Damage: During operation, if the belt suffers blockage, jamming, or impact from the frame, support structures, or lumpy materials, it can cause local damage or tearing, with the splice being a weak point. For reversible belts, due to their fixed splice lap direction, they are more susceptible to being scratched by sharp edges of equipment like scrapers or ploughs.

Environment and Aging: Exposure of the conveyor belt to acids, alkalis, oils, organic solvents, or direct sunlight accelerates rubber aging and reduces the toughness of the splice area.