How Electrochemical Machining Works

Electrochemical machining is another machining process that removes material from a workpiece to create the desired shape. This machining uses an electrochemical process to remove material and change the workpiece. Here we look at how electrochemical machining works and the benefits and drawback it can have for your machining process.

WHAT IS ELECTROCHEMICAL MACHINING?

Electrochemical machining uses both an electrolyte solution and an electrical current to alter the workpiece. Because electrical conductivity is necessary for electrochemical machining, the workpiece material must be conductive.

Electrochemical machining is the opposite process to electrochemical or galvanic coating. In electrochemical machining, the workpiece is taken as the anode, and the tool is taken as the cathode. These are both placed in an electrolyte solution and an electrical current is passed through the solution between them. The workpiece and tool are placed very close to each other but are not touching. As the electrical current is applied, the material removal from the workpiece happens at the atomic level, producing a smooth finish.

electrochemical machiningTHE ELECTROCHEMICAL PROCESS

In the electrochemical process, the way that material is removed from the workpiece is quite unique. The electrochemical reactions take place at the anode (workpiece) and the cathode (tool), as well as the surrounding electrolyte fluid. As the electrical current is applied across the electrode, ions move between the tool and the workpiece. In electrochemical machining, positive ions move towards the tool, and negative ions move towards the workpiece. This is the opposite of electroplating.

As electrons cross the gap between the workpiece and the tool, metal ions come away from the workpiece. These ions combine with hydroxyl ions to form metal hydroxides which are carried away by the electrolyte solution. The result is a smoothly finished workpiece with the desired material removed to create the necessary shape.

BENEFITS OF ELECTROCHEMICAL MACHINING

The electrochemical machining process has a number of benefits that make it a great choice for machining conductive materials.

Electrochemical machining produces an excellent mirror surface finish which requires no further finishing because there is no contact between the tool and the workpiece and no forces of residual stress are produced. Less heat is generated in the machining process because there is no contact and friction between tool and workpiece. High metal removal rates are also possible, and it’s even possible to cut small and intricate work in hard or unusual metals, such as titanium aluminides, or high nickel, cobalt, and rhenium alloys.

Complex concave and curved workpieces can be easily produced using the right convex and concave tools.

DRAWBACKS OF ELECTROCHEMICAL MACHINING

Despite the many benefits of electrochemical machining, there are some drawbacks. A saline or acidic electrolyte can increase the risk of corrosion for the tool, workpiece or equipment. An electrochemical machining setup also requires a high initial investment and high electrical running costs. Finally, only conductive materials can be machined. But electrochemical machining does add a very useful option for precise machining of some otherwise very difficult to machine materials.

Electrochemical machining is typically used as a last resort when conventional machining cannot be used. The reason is that it is a very slow process.

To find out more about electrochemical machining or whether it could be the right solution for your machining project, talk to the expert engineers at Inverse Solutions.