About RF Sealing
RF Welding, or Dielectric Heat Sealing, is the process by which electricity is converted into radio waves which are used to permanently bond multiple layers of plastic based (Primarily thermoplastics like pvc and polyurethane) materials together. This is a different process than others like gluing as the desired result with RF is a airtight, unified bond between polymers, not a surface bond.
The principle behind RF (Radio Frequency) Heat sealing, or Dielectric Welding, is the use of high frequency radio wave energy to produce molecular agitation in the thermoplastic materials like polyurethane and pvc. This agitation literally causes the materials to melt, or weld, together, typically forming a bond that is as strong as the original material.
To achieve the desired weld, or seal, the plastic components, like flexible films, are placed between a brass or aluminum die with the represent pattern of seal and a platen on the rf machine. The head of the machine, typically covered with a barrier such as fish paper or different thicknesses of Mylar as well as other materials, comes down and generates pressure. The RF turns on and is channeled through the material in the pattern areas only, fusing them together at those points.
One additional advantage to RF Heat Sealing versus standard Thermal Sealing is that the head remains in place once the sealing process is complete. A designated dwell time allows the material to return to a cooler temperature while pressure is still on the desired seal area, which in turn solidifies the seal.
Advantages of RF Sealing
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 the surrounding material does not have to be super heated to arrive at the target temperature.
With RF Sealing heat is only generated when the field is energized. Once the sealing cycle is complete, the heat is turned off. This allows for greater control over the amount of energy that the material sees over the entire cycle.
RF Tooling is usually run cold. This means that once the RF is turned off, the material stops being heated, but remains under pressure. There are occasions where additional heat is necessary as some materials need the extra boost. When that is the case, the tooling is preheated to a designated temperature and the RF is turned on to kick it over the melt temp.
RF Welds are clean because the only material required to produce the seal is the material itself. On the majority of projects, there is no need for messy adhesives and there are no by-products involved. There are some materials that require an additional adhesive, but we typically utilize a sheet form when necessary.