The radio frequency sealing process is not new, with manufacturers having used the process for over 60 years in order to create strong, durable products. However, in spite of its age, this technology is as reliable as it ever was. The process is also referred to as RF welding/sealing, dielectric sealing or high frequency welding.
How the Process Creates Strong Seals
Radio frequency sealing uses electromagnetic waves to heat two similar or dissimilar materials, which excites their polar molecules and causes them to rearrange, fusing together the two melted materials as heat is generated. The materials used in the process must have a polar molecular structure in order for it to work, which includes common plastics like polyurethane and PVC, as well as other polymers such as Nylon, EVA, PET and several ABS plastics.
The equipment involved in the process includes a table press and tooling dies. The two material surfaces are held on the table press that puts pressure on them. Then the electromagnetic waves travel through the narrow space between the die and table where sealing occurs. The combination of pressure and generated heat causes the materials to then melt and fuse together, forming a seal that is ultimately as strong or even stronger than the original materials.
The presence of a buffer is needed to facilitate the process, as it provides some electrical resistance to the radio frequency energy and prevents the process from putting holes in the material.
Fabricating Tough Plastic Products
Many industries rely on radio frequency sealing because of the strength of the bond the process creates. The medical, military and government industries use this process in many of their products, along with many other industries. Inflatable bladders for liquid containment and industrial curtain walls are simply a couple of the important products that use RF welding in their construction.