Seal wiresPTFE coated seal wire can seal plastic film and polystyrene. Seal wires are widely used in the food and packaging industries. The metal sealing wires are temperature resistant up to 260 Celsius and has non-stick properties due to the PTFE Teflon exterior.
What is a sealing wire?Sealing wires are used for impulse sealing in the packaging process. Sealing wires are manufactured from an 80-20% Nickel-Chrome alloy, depending on the control unit used. For electronically controlled sealing equipment, only sealing wires with low Ohmic resistance are recommended.
Sealing wires are available in different types and sizes. The standard sealing wires are provided with a PTFE coating which prevents sticking to the packaging film. Many sealing wires are supplied blank, but can also be provided with a PTFE coating. The sealing wires are available in almost any desired length and design, both with copper-plated and silver-plated ends. In addition, they are provided with end connectors.
Versions sealing wiresMost sealing threads are constructed in the following order:
- Hard glass fabric, for heat insulation;
- Sealing wire;
- Teflon, to prevent the sealing wire from melting to the film.
A silicone strip is usually placed on the overlying side as a back-pressure rubber. Without the external influences, the sealing wire will wear out during its service life due to annealing.
The different versions of seal wires
- PTFE-coated belts & cutting wires
- Copper plated ends
- Silvered ends
- Copper + nickel plated ends
Different types of sealing wiresThe sealing wires are available in different shapes:
- Hollow band
- Double seal
- Profile tire
- Round cutting wire
- Half round
- Oval cutting wire
- Triangular profile
- Laser cut sealing wires
- Endless sealing belts
What sealing wire do you need?Which type of sealing wire you need depends on a number of factors:
- Ohmic resistance: in addition to the material composition, the resistance of the sealing wire is determined, among other things, by the width and thickness of the wire. The greater the surface area (width x thickness), the lower the ohmic resistance.
- Shape: the shape of the sealing wire often determines the ohmic resistance. Several shapes are available, as described above.
- Endings: the ends are usually copper-plated or silver-plated. Both materials can conduct heat very well. This ensures that heat build-up on the contacts is limited, with the added benefit of a lower chance of wire breakage due to overheating. Resulting in a longer life with less production loss.
It is also possible to manipulate the heat output of the sealing wire by means of special copper plating. Additional copper plating can prevent a common problem when sealing plastic bags with a side gusset.