We all know that light duty conveyor belts aren’t ready to use right out of the box; they need to be spliced into a loop before use. However, some people experience cracking or breakage of the conveyor belt after only a short period of use, usually at the splice. Why does this happen?
Because the strength at the splice of a conveyor belt is generally weaker than the overall belt strength, and different splicing methods also result in different splice strengths.
Generally, mechanical splices have lower splice strength, only reaching 40% to 50% of the belt’s overall strength. Cold glue splices are slightly better, reaching 60% to 70%. Hot-melt splices are the best, achieving 80% to 90% of the strength. (Cold glue cannot be used on PVC and PU conveyor belts).
To achieve stronger splices, hot-melt splicing is typically used to create a loop. However, because it’s directly made into a loop, installation can be inconvenient, and some equipment may not be compatible. In such cases, many people choose mechanical splices for easier installation. Therefore, it’s important to choose the splice method that best suits your needs.
The light duty conveyor belt is a crucial component of a conveyor. The strength of the splice determines the lifespan of the conveyor belt. Joint breakage can cause production stoppages, machine jams, damage, and safety accidents, making proper conveyor belt splicing extremely important.
SCplus Belt Light Duty Conveyor Belt Splice Types
Toothed Joint: Toothed joints are the most common and strongest splicing method for light-duty conveyor belts.
Overlap Joint: Overlap joints are first finely ground using a grinding machine, then layered together with special adhesive, and finally fused together using a specialized splicing machine. The thickness of the overlap joint is consistent with the conveyor belt, and the tensile strength can reach 80% of the rated strength.
Steel Buckle Joint: Steel buckle joints are mainly used by manufacturers with complex machines that are difficult to disassemble. Different steel buckle models are selected based on the conveyor belt thickness. First, the steel buckles are attached to both ends of the conveyor belt using a steel buckle machine. During installation, the customer simply buckles the two ends together and secures it with a steel wire. While steel buckle joints are easy to disassemble, they can only be used on light-duty conveyor belts. Excessive tension can cause the steel buckle to pull apart, shortening the conveyor belt’s lifespan.
Reasons why light-duty conveyor belt joints to breakage:
1. Excessive load is the primary cause of conveyor belt joint breakage and the most common problem in practical applications.
When the weight of the conveyed material exceeds the conveyor belt’s design load capacity, the overall tension of the belt increases. The joint area, due to heat fusion, mechanical connections, or secondary processing structures, usually has slightly lower strength than the original belt. Long-term overload operation can lead to:
Tensile fatigue at the joint
Separation between joint layers
Stress concentration at the heat fusion point
Tearing due to sudden impact
Especially during startup or when material accumulates, the tension increases rapidly, increasing the likelihood of sudden joint breakage.
2. Insufficient roller diameter causes the conveyor belt to repeatedly and violently bend during operation.
The flexibility of the joint area is generally less than that of the original belt. When passing through small-diameter rollers:
The joint experiences greater bending stress.
Inner layer tension, outer layer compression;
Long-term repeated bending leads to fatigue cracks.
Especially with thick or multi-layered belts, running on small-roller equipment can easily cause premature aging and cracking of the joint.
3. Excessive tension: Many devices directly address conveyor belt slippage by increasing tension. However, excessive tension significantly increases tensile stress at the joint.
Problems caused by excessive tension include:
The joint is continuously under high tension.
The joint material’s elastic recovery ability decreases.
Microcracks gradually expand;
Ultimately, it breaks. The joint is not infinitely strong; under prolonged ultimate tension, breakage is only a matter of time.
4. Excessive operating speed: The faster the conveyor belt runs, the more times the joint passes through the rollers per unit time, and the higher the bending frequency.
At the same time, high speed also means:
Greater starting and stopping impact force;
Increased frequency of material impact on the joint.
Intensified dynamic tension fluctuations. High-speed operation exacerbates mechanical stress problems, significantly shortening the fatigue life of the joint.
5. Excessive Operating Time
Even under ideal operating conditions, conveyor belt splices will age over time.
Material hardening
Loss of elasticity in the adhesive layer
Molecular fatigue
Decreased bond strength
Aging is accelerated, especially in high temperature, high-humidity, oily, or dusty environments.
The splice itself is a “secondary processing part,” and its aging resistance is usually slightly lower than that of the original conveyor belt, making it more prone to problems first.
Therefore, when selecting a splicing method for a light duty conveyor belt, we need to comprehensively consider the overall conveyor belt operation and usage scenario. If you are unsure how to choose, feel free to contact the SCplus Belt engineering team; we are always ready to assist you.
