Anti-corrosion device for electrical discharge machining
AssigneeCharmilles Technologies S.A.
InventorRoger Delpretti
Life of this patent
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Abstract
Electrical discharge machining of a positively charged workpiece with a negatively charged wire electrode (2) by a pulse generator (3), with water as the dielectric fluid, generates a stray current known as "leakage current" that leads to a form of corrosion on the surface of the workpiece known as "anodic dissolution". A secondary circuit fed by a generator (5) and located between the workpiece and auxiliary electrodes (6), creates an equalizing current that cancels the leakage current and diminishes or eliminates anodic dissolution of the workpiece (1). The auxiliary electrodes (6) can be mounted on machining heads (7) with a non-conductive material (8) between the auxiliary electrodes.
Claims8
A machine for electrical-discharge machining of a workpiece by a wire electrode, comprising:
- a voltage pulse generator emitting pulses separated by waiting times and having a positive pole connected to the workpiece;
- a secondary equalizing circuit for protecting the workpiece against corrosion due to anodic dissolution by diminishing or eliminating said corrosion, said secondary equalizing circuit comprising at least one auxiliary electrode;
- and
- an auxiliary generator having a positive pole connected to said at least one auxiliary electrode and having a negative pole connected to the workpiece, said auxiliary generator is adjusted to create, between said at least one auxiliary electrode and the workpiece a current that counteracts a leakage current circulating between the workpiece and the wire electrode during a predetermined time period between pulses emitted by said voltage pulse generator.
Dependencies are inferred from the claim text.