There are many different processes that are used in the manufacturing of specialty items. Today, more than ever, technology provides options for sealing different types of plastics and films to create durable, sealed seams that can stand up to pressure, environmental stress and even high temperatures without failure.
Dielectric welding, also known as High Frequency or Radio Frequency (RF) welding, is one example of this type of technology. This process is used in a wide variety of applications to create bags, bladders and cushions that are used in industrial, medical, aviation and fabrication industries.
The Materials
The process of dielectric welding is typically used with various types of thermoplastic materials. Not all plastics or thermoplastics are a good match for this technology, so it will be essential to consider the options to create the seal based on the material.
The most commonly used thermoplastics for RF welding including PVC or polyvinylchloride and polyurethanes. These two thermoplastics contain what are known as polar molecules. These molecules are able to sustain the vibration and orient themselves to the change in the molecular charge to create the seal or the weld.
It is also possible to use RF welding with different materials, including PET, EVA and nylon. These materials may require modifications to the basic process including pre-heating the product in addition to the exposure to radio frequency power.
How it Works
As a basic and simple explanation, RF welding or dielectric welding uses very high frequencies in the RF or radio wave frequency range to generate electromagnetic energy directed at a specific location. The energy is directed through the use of metal welding bars that generate an alternating electrical and magnetic field.
When the thermoplastic is exposed to this field, the molecules in the plastic begin to vibrate or oscillate to change their orientation to the field. This movement of the internal molecular structure generates a significant amount of heat in a very small area.
The heat, in turn, causes almost an instant melting along that specific area of the plastic. The pressure of the welding bars meshes the two melted plastics to create a weld or a seam. Unlike gluing, the two sheets of the thermoplastic material fuse with each other, creating a solid and extremely durable seam that can hold up to pressure and heat without failure.
RF welding is a cost-effective, efficient and reliable way to create bladders and bags for all types of uses and applications. Durable and strong, these welds are reliable in all types of applications where the strength of the seam is an essential factor.
