15 Oct Wire EDM or sinker EDM: which process fits your tooling?

Electrical discharge machining removes material through controlled electrical discharges between an electrode and an electrically conductive workpiece. It is useful for tooling details that are difficult to reach or produce by conventional cutting. Wire and sinker EDM share that principle, but use different electrodes and access paths.

Wire EDM: a moving wire for through profiles

A continuously fed wire follows a programmed path through the workpiece. Typical tooling applications include punch outlines, die openings and through slots. An internal profile generally needs a way to introduce the wire, such as a start hole. The drawing must also allow for the wire path, corner geometry and required surface condition.

Sinker EDM: a shaped electrode for cavities

Sinker EDM uses a shaped electrode, commonly copper or graphite, to produce a corresponding feature in the workpiece. It can address blind cavities, ribs and other details that a through-cutting wire cannot create in the same way. Electrode design, access and flushing are part of planning the operation.

Choose the route from the drawing

A component may combine turning or milling, heat treatment, grinding and EDM. The useful question is which operations are needed to meet its geometry and final requirements. Specify the working surfaces, tolerances and finish on the drawing rather than assuming that a process name defines the result.

• Is the feature through the part, or is it a blind cavity?
• What material and material condition are required?
• Which dimensions, corner details and surface finishes are critical?
• What finishing or inspection is required after machining?

PFM lists both wire and sinker EDM within its precision manufacturing services. Review our mold and die components, or send a drawing so the process route can be discussed.

Technical reading: Makino’s overview of EDM processes and Sodick’s wire EDM overview. These explain the processes and do not describe or guarantee PFM machine models, tolerances or production capacity.