Patent ID: 6232574
Filing Date: 2001-05-15
Classification: B23K,H05H

Abstract:
A process for stopping a cutting operation of a plasma arc torch having an electrode comprising:directing a flow of oxidizing gas through a nozzle, said nozzle mounted at one end of said plasma arc torch and defining a plasma chamber between said electrode and said nozzle;conducting an electrical current through said electrode to form a plasma arc between said electrode and a workpiece;stepping down said electrical current at a time F for extinguishing said plasma arc;switching off said flow of oxidizing gas a predetermined time interval before time F; andswitching on a flow of non-oxidizing gas to the torch such that no later than time F said non-oxidizing gas has substantially completely purged said oxidizing gas from said plasma chamber creating an inert environment in said plasma chamber, whereby said plasma arc extinguishes in said inert environment.