An Experimental Study on Reducing the Formation of Dross when Cutting 1018 HR Steel Using a CNC Plasma Cutter

Abstract

Many manufacturers who cut metal use plasma arc cutting as part of their manufacturing process. Plasma cutters use electricity and pressurized gas to produce a temperature of up to 50,000 ºF at the cutting tip. These plasma cutters can rapidly cut through metals as much as 12 inches thick. The use of computer numerical controlled (CNC) plasma cutters allow manufacturers to rapidly cut even very intricate and detailed flat parts. This process is a tremendous improvement over traditional torch cutting, saw cutting, or other machining processes for producing near net shapes. It is faster and less expensive than most of the alternative processes available. There are several processing and quality factors that must be addressed when using a plasma cutter. The most common problem with plasma cutting is the formation of dross (resolidified metal) on the cut edge. The formation of dross on plasma-cut parts creates several problems in the manufacturing process. By carefully controlling the operating parameters, the formation of dross on the work piece can be minimized, which greatly increases the quality of the part and the efficiency of the production process. Efficient operation of a CNC plasma cutter to minimize the formation of dross requires controlling several variables in the process. These variables include: material type and thickness, arc current (amperage), cutting speed, cutting-gas pressure, cutting tip size, and the gap between the cutting tip and the work piece. Experience with plasma arc cutting and research on the subject reveals that the variables that most affect the formation of dross are arc current, cutting speed, material thickness, and nozzle size. A study involving these four variables will be performed to determine the optimum setup for the CNC plasma cutter to minimize the formation of dross.