Device and method for electrochemical reduction

Abstract

A device for electrochemical reduction of a workpiece (10) includes a workpiece (10), an electrode (20), and an electrolyte (30), which is located between electrode (20) and workpiece (10). The electrode (20) is moved close to the workpiece (10) with a small gap dimension (21), and a processing of the workpiece (10) occurs through a flow of current between electrode (20) and workpiece (10) through the electrolyte (30). In addition, a sonotrode is positioned to introduce sound waves.

Description

[0001] Priority is claimed to German Patent Application DE 10 2004 041 780.8, filed Aug. 28, 2004, the entire disclosure of which is incorporated by reference herein. FIELD OF THE INVENTION [0002] The present invention relates to a method for electrochemical reduction of a workpiece. BACKGROUND [0003] For reduction, a workpiece on which a shaping or surface processing is to be undertaken by removal of material, at least in its area for processing, is brought into the environment of an electrolyte and the workpiece is placed in electrical contact with the ground. An electrode is brought into proximity with the workpiece and is shaped according to the necessary processing. A current flows through the electrolyte which is located in the intermediate space between the electrode and the workpiece being processed. An electrochemical removal of material from the surface of the workpiece occurs between this electrolyte and the workpiece due to the flow of current. [0004] Depending on the wo...

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Benefits of technology

[0008] An object of the present invention is to enable high processing precision by allowing the reduction gap between electrode and workpiece to have a small gap dimension, and also to reliably prevent the occurrence of depositions from passivation layers and concentrations of removal products in the electrolyte.

[0019] According to an advantageous embodiment of the present invention, the sound waves of the sonotrode are coupled at least indirectly into the electrolyte, and the flow of electrolyte through the reduction gap is produced. At the same time the introduced sound waves, in particular ultrasonic waves, may support the flow of the electrolyte through the reduction gap, in particular actively, and produce a pump effect. The sound waves generated by the sonotrode are in particular ultrasonic waves, it preferably being ensured that no standing waves are formed in the electrolyte in the area of the reduction gap. It corresponds here to an advantageous embodiment if the sound waves are coupled into the electrolyte indirectly through the workpiece or the electrode. Coupling the sound waves from the sonotrode via the workpiece has the advantage in particular that the sound waves pass through the workpiece, and that the development of passivation layers in the area of the surface of the workpiece is therefore prevented in the processing area, i.e., in the reduction gap, in an especially advantageous way.

Problems solved by technology

Furthermore, in reduction processes, non-uniform distributions of the removal products of the workpiece in the electrolyte may occur, especially when the reduction gap between workpiece and electrode is very small, as is necessary to achieve high precision of the surface processing and the shape stability.

This may result in uneven removal, and thus in deviations of the achieved shape from the desired shape of the workpiece after the processing.

Furthermore, because of the deposition of removal products in the reduction gap, occasional disruptions of processing may also occur due to short circuit currents, which result in unwanted damage to the shape of the electrode and consequent processing imprecisions, but also to damage to the workpiece in the vicinity of the short circuit current.

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