Experimental Investigation of Thermal Strain Caused by Electrical Discharge Machining on Stainless Steel SUS430

In this work, an experimental investigation of thermal strain caused by electrical discharge machining on a stainless-steel (SUS430) plate using digital image correlation is proposed. A speckle pattern was prepared by grinding the surface of objects to obtain a reliable and accurate measurement. The potential of the proposed system for thermal strain measurement using digital image correlation, combined with the ring-core method for electrical discharge machining, was evaluated. Ring-core machining involves milling a ring core around the inside of a displacement field analyzed by digital image correlation. It was observed that the peak strain presented in the outer ring and the strain decreased inward toward the inner core. Experimental results revealed that the maximum thermal strain caused by electrical discharge machining was proportional to the drilling depth.