Dielectric Heating (or Capacitance Heating) is the method of heating non-conductive materials. Dielectric heating, also known as electronic heating, RF heating, high-frequency heating and diathermy, is the process in which radio wave or microwave electromagnetic radiation heats a dielectric material. This heating is caused by dipole rotation. In comparison to Induction heating, Dielectric heating is a non-contact and non-conductive heating method that can used for heating any kind of material.

With dielectric electrostatic heating, the material to be heated is placed between two electrodes, usually spaced the same distance apart at all points. High frequency RF Energy is applied to the plates and heat is produced simultaneously throughout the area of the charge, usually at a rather rapid rate. The oscillating field passes through the material and as the field direction changes, the polarisation of individual molecules reverses rapidly, causing friction and hence heat. The higher the frequency, the greater the movement. Typically, frequencies in the range 5 MHz to 80 MHz are used. This technology is used in Wood Gluing, RF Drying and Plastic Welding.

Applications of Dielectric Heating or High-Frequency RF Electronic Heating

  • Plastic Welding – The bonding of plastic using RF is the industry standard for many applications including the manufacturing of: Inflatable Toys, Medical Bags, Tents, Truck Covers.
  • Plastic Preheating – plastic preheating has applications such as: Semiconductor Packaging, Melamine.
  • Textile Drying – High power radio frequency drying is the most efficient process for the removal of moisture from textiles.
  • Wood Glue Drying – The wood industry has many applications which use RF tubes. RF can be used to remove the moisture from lumber and plywood, embossing, forming or laminating to fiberboard or for OSB and chip board curing.
  • Food Drying – Using RF in the food industry has many advantages and can be used for various processes such as: Post Bake Moisture Removal, Pasteurization / Sterilization, Preheating or Precooking.
  • Dielectric Heating is used in the pre-curing of practically all types of plastics, cellulose fibers, and celluloid. Its field also covers the heating and treatment of rubber, wood paper, ceramics, cork, textiles, and many other dielectric materials.