High Frequency Welding is a process in which high-frequency alternating current is used as the heat source.The high-frequency AC alternates between 100 and 800 Kilohertz. This high-frequency current has two unusual features. First, this current only flows on the surface of the conductor and this is known as skin effect.
Second,if two conductors are placed close to one another and high-frequency current is passed through both of them then current concentrates on the adjacent surfaces of the conductors.This is known as proximity effect.
The welds produced by this method are generally “forge welds” meaning that no filler material is used and also no edge melting takes place.In this process high-frequency AC is applied to the edges of the work pieces which softens them and then pressure is applied onto the work pieces.The pressure fuses the work pieces together.The current is either applied directly or by using an induction coil.The work pieces are then allowed to cool down and a joint is formed.This method is also known as Dielectric Sealing or Radio Frequency Heat Sealing.
This Plastic Welding process is generally used to weld plastic materials with dipoles,for ex polyamides (PA),polyvinyl chlorides (PVC), etc.If the work pieces are ferromagnetic then induction welding can be used to weld them.In this method metallic or ferromagnetic materials called susceptors are used to weld the work pieces together.These materials absorb the heat from induction coil and transfer it to the work pieces by the process of induction.