The Plasma Arc Welding process is an interesting and technical process, it can be considered very basic, but that said, there are many things that can go wrong.
We get a lot of calls from customers using Plasma Arc Welding torches that have failed. So we developed a check list that we go through to determine what caused the torch failure.
Generally the PAW torch body arcs out internally, which can be caused by low quality replacement parts, inferior tungsten electrode, poor or inconsistent tungsten electrode grinding, dirty parts, gas leaks in the supply hoses, worn out power cable leads….
Most commonly, however, plasma arc welding torch failure is caused by incorrectly installed replacement parts.
That’s right, operators consistently install the ceramic electrode insulator/gas distributor in the wrong direction, or worse yet they modify it by breaking of portions of it! This is common on the Thermal Dynamics 3A series torches.
The part #9-2240 (photo) is a technical ceramic molded piece that has a series of strategically placed gas channels and distribution ports which optimize the inert gas that flows through the torch and directs it to the constricting tip which then forms a superheated column of Plasma gas. It is absolutely necessary that this piece be installed with great attention to cleanliness and that it is positioned correctly.
Note: there is a newer version of the part #9-2240, pictured below.
The end pointing to the top left corner is the sleeve or collar end which is directed up to the top of the torch toward the collet / insulating cap.