Long Dwell technology for flow-wrapping
The Long Dwell system is a sealing technology used in flow pack packaging machines to ensure stronger seals even at high packaging speeds.
This solution is particularly suitable when using films that are difficult to seal or packaging materials that require a longer sealing time to achieve a stable closure.
In high-speed packaging, the time available for sealing the package is very limited.
The Long Dwell system increases the contact time between the sealing jaws, allowing more reliable seals to be achieved even with complex materials.
- better sealing quality
- greater process reliability
- ability to work with complex or laminated films
- high packaging speeds
The system uses “D”-shaped cams that allow the sealing jaws to combine a rotary movement with a translational movement.
This mechanism allows the sealing jaws to remain coupled for a longer time compared to traditional rotary systems, increasing the effective sealing time.
During this phase, the cutting knife separates the packages while maintaining the continuity of the packaging process.
During the sealing phase, the jaws remain coupled for a significant portion of the system’s rotation.
The flat part of the “D”-shaped cams corresponds to the section where sealing takes place, allowing contact between the surfaces to be maintained for a longer time.
After sealing, the packages are cut and separated, continuing their path along the machine’s output conveyor.
The sealing jaws continue the rotary movement along the circular part of the cams until the next packaging phase.
Long Dwell technology is used in packaging lines that require high performance and consistent sealing quality.
It is particularly suitable for:
- high-speed packaged food products
- polypropylene and polyethylene films
- laminated films or complex materials
LMC Pack manufactures Long Dwell sealing units and components for packaging machines, also developed according to customer technical specifications.