RF Welding

Radio Frequency Welding is the process by which electro magnetic energy is used to permanently bond thermoplastic materials together.  This is different than other processes as the desired result is a hermetic, cohesive bond between the polymers. This type of welding can only occur between highly dipolar materials that are excited by an alternating magnetic field.

Dielectrics is an established leader in thermoplastic welding for the medical device industry, and best known for our expertise in Radio Frequency Welding (also referred to as "RF welding", "Dielectric sealing", "High frequency" welding, or "heat sealing"). The RF Welding  process uses radio frequency energy to produce molecular agitation in thermoplastic materials (e.g. thermoplastic polyurethane, PVC, PVDC, EVA, PET, nylon and other customized resins) such that they melt and flow together, forming a bond that is as strong as the original materials.

During welding, components are clamped under pressure between machined electrodes. A magnetic field is generated between the electrodes, passing through the components, fusing the material together. 


Advantages

RF welding provides several advantages over alternative welding technologies:

  • RF sealing occurs from the inside out by using the material itself as a heat source.  The heat is focused at the weld target so that the surrounding material does not have to be super-heated to arrive at a target temperature at the joint.
  • With RF heat is generated only when the field is energized. Once the generator cycles, the heat is turned off. This allows for greater control over the amount of energy that the material sees over the entire cycle. In addition, RF-generated heat does not radiate off the die like on a heated die. This prevents heat-degredation of the material abutting the weld.
  • RF tooling is usually run "cold". This means that once the RF is turned off, the material stops being heated, but remains under pressure. In this fashion it is possible to both instantly heat, weld, and cool the material under compression. More control over the weld results in more control over the resulting extrusion, thus increasing the weld strength.
  • RF welds are "clean" because the only material needed to produce an RF weld is the material itself. There are no adhesives or by-products involved in RF welding.