(http://www.davison-machinery.com )High frequency welding (often abbreviated HF welding or RF welding) is a manufacturing process where two plastic parts are welded together using an electromagnetic field.

Common products manufactured with high frequency welding are tarpaulins, tents, ceilings, advertising banners, waterbeds, inflatable boats, medical and especially blod and urine-bags, tensile structures, conveyor belts, rain clothing etc.

Principle and advantage of high frequency welding

The main principle of high frequency welding (HF welding) is based on di-electric heating of the material to be welded.

The objects that needs to be welded are clamped together between two metal electrodes and a high frequency voltage is supplied. As a result the molecyles in the material starts to vibrate and heat up. Eventually the material will melt, and the force supplied by the electrode will melt (fuse) the two surfaces together. After cooling a permanent seam has been created. The resulting weld seam can be as strong - or even stronger - than the surrounding material.

The great advantage of HF welding is the speed of welding: The material is heated from the inside and fuses quickly, within few seconds.

Compared to high frequency welding, a lot of other methods (hot air, infrared radiation, laser) the energy /heat is supplied from the outside. This means that the heat must first penetrate the material in order to heat the contact-surfaces, thus risking to burn the top layer of the welded material.

You could compare this to heating your food in the microwave oven vs in a traditional oven.

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