Understanding the Wire EDM Process, EDM filters
Wire EDM is extremely accurate. Many machines move in increments of 40 millionths of an inch (.00004″) (.001 mm), some in 10 millionths of an inch (.00001″) (.00025 mm), and others even in 4 millionths of an inch (.000004”) (.0001 mm).
Machines can achieve accuracies of +/-.0001” (.0025 mm); however, skim cuts need to be made to obtain such tolerances.
Extremely fine finishes of below 15 RMS can be produced with wire EDM. (Some machines can produce even a mirror finish.) Wire EDM produces an excellent finish even in the so-called “rough cut.” Customers are often amazed when shown the fine finish of a single-pass cut. This fine finish is present even after very large parts are cut, as in Figure 5:2. In other cutting operations, such as lasers and abrasive water jet, the larger the part, the rougher the finish. Wire EDM produces a smooth finish because the wire electrode goes through the entire part, and spark erosion occurs along the entire wire electrode.
he wire never contacts the workpiece. If the wire would contact the workpiece, there would be a short circuit and no cutting would occur. The wire electrode cuts by means of spark erosion, thereby leaving a path slightly larger than the wire. A commonly used wire,
When the wire turns a corner it can produce a sharp edge on the outside corner, but it will always leave a small radius on the inside corner as demonstrated in Figure 5:4. The size of this radius is determined by the wire diameter plus the spark gap.
To produce very sharp outside corners, skim cuts are made. Having small corner radii on the outside corners can prevent the need for skim cuts; this also reduces wire EDM costs. In stamping dies, sharp corners usually wear first, so a small outside radius is preferable.
To produce very sharp outside corners, skim cuts are made. Having small corner radii on the outside corners can prevent the need for skim cuts; this also reduces wire EDM costs. In stamping dies, sharp corners usually wear first, so a small outside radius is preferable.
Understanding the Wire EDM Process, EDM filters
