Surface treatment of heating band ends
The heating bands generate the necessary heat to seal the films thanks to their electrical resistance. If the heat dissipation is not constant - as it is the case, for instance, near the connections – the result will be a local overheating. The most frequent cause for a premature band rupture is such overheating.
The surface treatment is applied to reduce the electrical resistance of the connections in order to avoid extreme temperature rises. The methods for the application of the coating and its thickness must be adapted to the heating band cross section which helps prolong the service life considerably. Coatings that are of poor quality or too thin may only serve decorative purposes.
The following methods may be applied:
Silvering
- proven method since the beginning of packaging machinery engineering
- thickness cannot be controlled, basic resistance is higher than that of copper
Copperplating
- standard, suitable for almost all applications
- partial copperplating possible (zebra bands)
- thickness can be controlled depending on individual application
Copperplating + nickel coating
- no corrosion in hostile environments or during long storage periods
- standard type for contoured sealing bands
Copperplating + plated gold
- excellent bonding at the bar heads, therefore very precise reference and actual temperature values in combination with electronic control units.
- for best seam quality applications
Connections
