ESAB Welding and Cutting Products, based in South Carolina, USA, has turned to Victrex® PEEK™ polymer for the electrical insulators in its plasma cutting torches.
Replacing a leading brand of polyimide, the polymer offers the same insulation and high temperature performance but provides more cost-effective processing and superior heat ageing and creep resistance.
Plasma cutting torches are used to cut and fabricate metal parts. They utilize a very high voltage electrical discharge to create an arc, known as the pilot arc, between the electrode (torch body) and the work piece. The arc is forced through a small hole in the nozzle head, together with an extremely high temperature effluent of gas, such as air, onto the metal part.
A plasma cutting torch has typically two electrical potentials which must be insulated from each other. Stan Severance, Staff Engineer at ESAB explains: “The Victrex® PEEK™ polymer insulator is located in the head of the torch where it has to separate the electrode potential from the nozzle potential. The insulator must withstand very high voltages of up to 10,000 volts at high frequencies, and extremes of temperature, especially in air-cooled torches”.
ESAB tested a variety of different materials before switching to Victrex® PEEK™ polymer, which provides long-term operating reliability and consistent ease of processing.