Electrochemical Machining Processes

Electrochemical Machining (ECM)

• ECM uses electrical energy in combination with chemical reactions to remove material from a workpiece.
• It's the reverse of electroplating, removing material instead of adding it.
• The workpiece must be an electrically conductive material.

Process Overview

• The ECM process involves an electrode (tool) that is separated from the workpiece by a rapidly flowing electrolyte.
• Material is removed from the anode (positive pole) workpiece and transported to the cathode (negative pole) tool in an electrolyte bath.
• The electrolyte, typically a salt solution (e.g., sodium chloride or sodium nitrate mixed with water), carries off the removed material.
• The flowing electrolyte also removes heat and hydrogen bubbles created during the process.

Electrode and Tooling

• Electrode materials used include copper, brass, or stainless steel.
• The tool has an inverse shape of the desired part.
• The tool size and shape must allow for a gap between the tool and workpiece.
• The die is gradually lowered into the workpiece.

Operating Conditions

• Low voltage (5-25 V) and high current (up to 700 amps) are used in the ECM process.

Advantages

• No thermal damage to parts
• Low tool wear
• Relatively high metal removal rates for hard and difficult metals
• Capable of machining complex parts and hard materials
• High production and high tolerances

Electrochemical Deburring (ECD)

• A modification of ECM used to remove burrs or round sharp corners on metal parts.
• The electrolyte flows through the hole to carry away burr particles.
• Cycle times are typically less than a minute.

Electrochemical Grinding (ECG)

• An improved electrochemical grinding wheel electrode consisting of electrically conductive abrasive grains bonded with non-conductive material.