Electrochemical Machining (ECM) is based upon Faraday's police push clit of electrolysis. Faraday's police push clit states that the the majority of a metallic element altered past times the electrode is proportional to the quantity of electrical charges transferred to that electrode.
- In ECM the removal of metallic element is controlled past times the anodic dissolution inward the electrolyte.
- The workpiece acts equally the anode
- The tool human activity equally cathode.
- The electrodes should endure placed closely amongst a gap of virtually 0.5 mm .
- The anodes too cathodes should endure immersed into electrolyte. (Here Sodium Chloride)
Please Read :
- Abrasive Jet Machining Process
- Water Jet Machining Process .
- Ultrasonic Machining Principles
- Electrical Discharge Machining (EDM) Principles
Schematic example of the electrochemical-machining (ECM) process
The primary principles of ECM are equally follows -
- A potential departure is maintained betwixt the electrodes equally a lawsuit ions existing inward the electrolytes migrate towards the electrodes.
- Conventionally positively charged ions are attracted towards the cathode too negative ions are attached towards to the anode. And therefore menstruum of electrical flow is initiated inward the electrolyte.
- The set-up is kept stationary too tool is fed linearly.
- The desired total of metallic element is removed because of ion migration towards the tool.
- For keeping the tool prophylactic from harm a continuous provide of electrolyte is ensured past times pumping it at high pressure level (15kg/cm2).
- In this procedure the temperature generated is really depression too no spark is produced too therefore at that topographic point isn't whatsoever range of metallurgical changes inward the job.
- When electricity is supplied to the metallic element ions of the w/p is pulled out. The positive ions of the metallic element reacts amongst the negative ions acquaint on the electrolytic solution too hydroxides of metallic element too other components. This hydroxides are precipitated too washed away past times the electrolytic solutions.
- In Electrochemical Machining the tool too workpiece doesn't come upwards inward straight contact amongst each other so negligible article of apparel too tear is observed.
- Metal removal charge per unit of measurement is high too voltage supplied is really low.
- The metallic element workpiece is non damaged due to thermal stresses.
- Dimensions upwards to 0.05 mm tin give the sack easily machined .
Examples of parts made past times ECM
Different parts made past times electrochemical machining. (a) Turbine blade stuff : nickel alloy (b) Thin slots on a 4340-steel roller-bearing cage. (c) Integral airfoils on a compressor disk.
(a) Schematic example of the electrochemical-grinding process. (b) Thin slot produced on a round
nickel-alloy subway past times this process.
Flow Arrangement of the
Electrochemical Grinding (ECG) Principles
(a) Schematic example of the electrochemical-grinding process. (b) Thin slot produced on a round
nickel-alloy subway past times this process.
Functions of Electrolyte
- The electrical flow is carried betwixt the tool too the w/p through electrolyte.
- The produced estrus is dissipated past times the liquid electrolytic solution.
- The production of machining is removed past times the solution.
- It keeps the reactions continuous past times supplying the elements necessary for the reaction.
What Should endure The Criteria of Selecting Electrolyte inward Electrochemical Machining (ECM) too Grinding (ECG)
The pick of the electrolyte should endure done past times considering the next matters -
· Required Machining rate
· Required Dimensional Accuracy
· Surface Texture too Integrity
The properties of Electrolytes
- High Electrical Conductivity
- High Current Efficiency for machining
- Good Surface complete too integrity is necessary
- Composition of the electrolyte too construction of the stuff controls the finally surface texture.
Flow Arrangement of the
Perfect electrolyte menstruum across the machining tool is mandatory for proper machining.
cavitation is probable to endure occurred inward the tool so proper tending is necessary to drib dead along the
tool inward shape. Tool blueprint must ensure the uniform menstruum of electrolytic solution inward all
the machining areas. Optimum menstruum of the electrolyte is desired because excessive
menstruum can cause erosion of the tool.
Mainly 2 types of flows are used –
Mainly 2 types of flows are used –
1. Divergent flow
2. Convergent flow
Convergent menstruum provides a smoother menstruum of electrolytes. At kickoff the electrolyte has to transcend a
chamber known equally ‘dam’. The dam is used to pressurize the are exterior the working tool.
Advantages of convergent menstruum system.
- Improved Surface finish
- Improved Uniform too predictable side over cutting equally good equally forepart machining gap.
- Less prone to arcing.
- Clean operating environment
- Stray currents arrive possible to eliminated unwanted machining.
But it is also to endure mentioned that machining inward convergent menstruum is much expensive than divergent flow.
Advantages of Electrochemical Machining (ECM)
- Accurate Machining
- No straight contact betwixt tool too job.
- Negligible article of apparel too tear of the tool.
- Environment friendly
- no thermal or mechanical stress is induced on the tool.
- There is no contact betwixt worpiece too the tool so its is possible to machine non-rigid too opened upwards w/p.
- Jobs amongst complex geometric shapes tin give the sack endure machined amongst ease accurately too repeatedly.
- ECM is a fourth dimension saver when compared to conventional machining.
- During drilling several holes tin give the sack endure done at once.
- Deburring tin give the sack endure done inward hard to access areas.
- Fragile too brittle materials which are prone to harm tin give the sack endure machined easily inward ECM without bang-up or breaking.
- Surface complete upwards to 25 μ inward tin give the sack endure achieved.
Disadvantages of Electrochemical Machining (ECM)
- Sometimes this procedure is costly because the equipments are expensive.
- Continuous provide of electrolytic solution is mandatory.
- Steady voltage or potential departure should endure maintained.
- Rigid fixturing is required to withstood the high menstruum charge per unit of measurement of electrolytes.
- Designing the tool is arduous because it must endure insulated to maintain the perfect conducting paths towards the workpiece.
- Corrosion gratis stuff is needed for the construction too the electrolyte treatment unit.
- If hydrogen is liberated at the tool surface so it is possible to endure from hydrogen-embitterment of the surface.
- There is possibility of damages because of sparks.
- Conventional machining techniques hit to a greater extent than improved fatigue properties than ECM.
Applications of Electrochemical Machining ECM
- ECM is mainly used inward the areas where conventional machinig techniques are non viable . One of the primary applications of ECM is flora inward the aerospace industries where accuracy is really of import when complex shaped hard to machine materials are needed to endure machined.
- Different Industrial techniques convey been developed on the footing of Electrochemical Machining Such as
a. Electrochemical Cutting
b. Electrochemica ECM
c. Electrochemica broaching
d. Electrochemica drilling
e. Electrochemica deburring