Strap Joint / Weld Joint
A strap joint, also known as a weld joint, is the connection between the two ends of a plastic strap. The weld joint can be created through either vibration or heat tongue sealing, depending on the technique used by the strapping machine.
Did you know that the strength of the strapping is only as strong as the weld joint? This means a weak or poorly executed weld joint can significantly reduce the overall strength of your strap, making it the most likely point of failure.
Strap Joint Strength / Weld Joint Strength
The weld joint strength indicates the quality of the connection between the two plastic strap ends until the weld breaks. It is measured in Newtons (N) and is always lower than the indicated breaking strength of the plain, unused strap, as provided on the datasheet.
The value of the weld joint strength is influenced by the adjustment and settings of the machinery in combination with the strap material used.
Strap Joint Efficiency / Weld Joint Efficiency
The weld joint efficiency, sometimes referred to as weld efficiency, strength efficiency, or breaking load efficiency, is expressed as a percentage. This value represents the ratio between the weld joint strength and the breaking strength of the unused strap.
For comparison:
- High-quality PET straps can achieve a weld joint efficiency of 70-80%. In practice, this value can vary widely and typically ranges from 30-80%.
- PP straps have a much lower strap joint efficiency, averaging around 40%.