EDM Cutting
EDM cutting, a process known as wire EDM, is the most effective method of making incisions into hard or soft metals to form many different products. It is a process used to cut hard metals and other materials which are difficult to machine using conventional methods. Instead of physically cutting or grinding, the material being processed is eroded away using electrical discharge sparks that come from a wire made of brass, zinc, copper or tungsten. While there is no contact between the wire and work piece, the sparks produced as a result of electrical conductivity wear away the material in the desired pattern. Metals that are EDM cut must be electrically conductive and common examples include aluminum, copper, zinc, tin, titanium, stainless steel, gold, lead, silver, iron, bronze and super alloys. A wide range of objects is produced using EDM machining such as gears, robot parts, jewelry, stripper plates and molds.Complex patterns, intricate contours and delicate cavities are easily formed by rapid, controlled, repetitive spark discharges. As it is a versatile process, use of electrical discharge machining is wide spread and the process is commonly found in the electronics, tool and die, aerospace, robotics, medical, automotive and metal sculpting industries.
No preheating is necessary for EDM cutting, but since the sparks reach 10,000ยบ C, chiller systems are a part of the process to control the operating temperatures. EDM cutting can cut into materials that are as thin as a fraction of an inch to as thick as several inches. Originally intended as a manual process, innovations in metal forming technology have improved and now with CAD/CAM computer programming, CNC EDM is a fully automated, computer controlled process achieving high tolerances and repeatability. EDM takes place in a bath of dielectric fluid, which washes away debris, conducts electricity between the electrode and the work piece and prevents premature sparking. The pattern, which is often quite complex, is uploaded into software and then guided by a CNC (computer numeric controlled) machine. The wire, usually made of brass, comes extremely close to touching the work piece and leaves a small gap where the sparks create intense heat and vaporize the metal as the wire slowly moves forward. The work piece is tightly clamped down and held in place while the wire moves in the path of the part pattern eroding the unwanted material away. The finished product has smooth, matte edges, no burrs and sharp corners that are slightly rounded. Despite it being a slow and complicated process, EDM parts manufacturers are able to provide customers with low or high volumes of products that have close tolerances and a high degree of uniformity.
