ECM Electro-chemical Machining
ECM is a process in which "the controlled removal of metal by anodic dissolution of the workpiece in an electrolytic cell where the workpiece acts as anode and tool acts as cathode".
Working :-
- ECM process is based on Faraday's Laws of electrolysis, where workpiece acts as anode and tools acts as cathode.
- The tool and workpiece are held close to each other with a small gap (upto 0.5 mm) between them.
- A D.C. Voltage of about 3-30 V is applied between the tool and workpiece, and electrolyte is pumped into the gap.
- Due to this flow of ions, electrochemical reaction takes place and hence there is removal of metal from the workpiece in the form of sludge.
- This sludge is taken away from the gap by the electrolyte which is flowing continuously.
Advantages of ECM :-
- Materials which are good conductor of electricity can be easily machined with no effect on mechanical properties of material.
- Complicated shapes can be easily machined.
- MRR is high as compared to other processes.
- As there is contact between workpiece and tool, then also took wear is almost negligible.
- The machined surface is stress free.
Disadvantages of ECM :-
- Only electrically conductive materials can be machined.
- Due to continuous supply of electrolyte in the process, there is corrosion and rusting of workpiece, tool and used fixture.
- Fine radius can not be generated.
- More floor space is required.
- Initial cost of equipment and tool is quite high.
Applications of ECM :-
- It is mainly used for hard and heat resistant materials.
- For producing blind holes, a pocket in forging dies ECM is preferred.
- Small deep holes, such as in nozzles can be drilled.
- Deburring of parts can be done.