A Novel High Efficiency Electrical Erosion Process – Blasting Erosion Arc Machining

A novel low cost, high efficiency material removal process namely the Blasting Erosion Arc Machining (BEAM) is proposed and implemented to perform bulk removing of alloys including the difficult-to-cut materials. Compared with conventional EDM process, the BEAM process erodes the work piece materials with electrical arcing instead of sparking. The most critical enabling mechanism of BEAM is how to make the arcing plasma column break off, and resulting in a consequent blast effect, by which the molten material is blown off from the molten pool efficiently. In order to avoid continuous and steady arcing, a strong multi-hole inner flushing is a prerequisite for the BEAM process. During BEAM, the high velocity flushing induces a strong hydrodynamic force into the gap, which distorts, elongates or even breaks the arcing plasma column. During the arc breaking process, an extremely strong blasting will blow off the molten material explosively. This arc breaking mechanism is named hydrodynamic arc breaking mechanism and it is the principle of BEAM process. The preliminary experiments demonstrated the material removal rate of the BEAM process is extremely higher than that of traditional EDM or even the milling process. For example, the MRR of BEAM of Inconel718 exceeds 11,300/min as well as the tool wear ratio is lower than 1%. Obviously, BEAM is a promising process in the high efficiency machining of the difficult-to-cut materials. Besides, it is also an environmentally friendly machining process because the working fluid is water-based dielectric rather than hydrocarbon dielectric oil.