CNC 와이어 방전가공기의 반복가공을 통한 직진정밀도 향상에 관한 연구

A Study on the Improvement of Straightness Accuracy through the Repeated Cutting in CNC Wire-EDM

In wire cutting machining, vibration occurs due to repulsive force by discharge, causing eruption of machining liquid above and below the surface of machined object, and becomes a major source of deteriorating straightness accuracy and surface roughness due to the difference of the specific resistivity of machining liquid that passes through machined surface. In order to find out the changes of such deteriorating element, this paper measured and analyzed straightness accuracy and surface roughness through repetitive machining up to 6th sessions by changing the offset amount of alloy tool steel(STD-11) widely utilized as mold material, and proposed efficient machining technique of wire cutting machine. As a result of the experiment, the cut shape by and large was slightly concave at the first machining and convex from the 2nd to the 5th machining, and surface roughness was dramatically improved up to 4th or 5th machining, but did not show any significant change from the 5th or 6th machining. In conclusion, to improve straightness accuracy and surface roughness through repetitive machining of wire cutting, machining up to 4th times may produce the best results.