Wire EDM
Also known as wire erosion, wire EDM is one of the most common types of electrical discharge machining, which uses the most accurate types of machining equipment to manufacture hard metals and other materials that are difficult to machine cleanly with conventional mechanical-cutting methods. As a highly-accurate tooling method that uses electrical energy to cut, drill, etch and machine metal parts, wire EDM has a long list of applications such as stripper plates, gears, punches, stamping die components, and producing plastic molds. Industries that utilize wire EDM machining technology include electronics, tool and die, aerospace, robotics and medical.
In order to wire electrical discharge machine a metal part, a hole or perforation must already be made in the metal - this is usually done by small hole EDM. Wire EDM can then be accomplished through sparks, which are electrical discharges that can generate heat anywhere from eight to twenty thousand degrees. A thin brass wire is fed through the workpiece and clamped on both ends by diamond guides, then the wire cuts through the metal in a specified pattern guided by CNC machine arms. The wire electrode is used to generate the series of sparks. There is no actual contact between the electrode and the work piece, but rather a conductive path that is established between the electrode and the material. This process takes place in a bath of dielectric fluid, which prevents premature sparking and flushes away debris, conducts electricity between the electrode and the work piece and then flushes out the melted material. Wire EDM is used for cutting shapes through a selected part or assembly.
Wire EDM offers several advantages compared to conventional cutting methods including the ability to machine complex shapes and patterns and to machine very hard materials, such as stainless steel, titanium, carbide and inconel, at close tolerances. Wire EDM is also a cost-effective and flexible machining process. Disadvantages of wire EDM include electrode wear and a slow rate of material removal. However, some technological advancements in wire cut EDM include using multiple heads for cutting two materials at once, control for preventing wire breakage, automatic self-threading features and new programmable machining strategies for wire EDM optimization.