Some special applications of

Electrochemical Machining

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Electro chemical cutting off Electro chemical milling

Electro chemical turning

Electro chemical turning of thin plate

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Electro Chemical Shaping

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Full Form Electro Chemical Shaping

Design of cathode tool shape to obtain profile of turbine blade

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Electro Chemical Machining of Irregular Shaped Hole

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Electrochemical Grinding

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Electro Chemical Grinding

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Grinding wheel with metallic bond in ECG

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Electrochemical dissolution and Mechanical abrasion in the

Machining Gap during ECG

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Conventional grinding Electro chemical grinding

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Phases of material removal in electro chemical grinding

Phase 1: pure ECM, Phase 2: mechanical grinding, Phase 3: electrochemical polishing

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Process variables

Voltage –Low voltage less electrochemical action more abrasive cutting with minimal deburring. Higher voltage more electrochemical and less abrasive action. Too much voltage electrical arcing.

Electrolyte Flow –Enough flow creates electrochemical cell at the point of the cut and complete the processToo much flow may remove metal beyond the desired cut area.

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Process variables

Feed Rate – Feed rate in ECG is similar to creep feed grinding generally in the 13 to 100 mm/minute range depending on size of the cut and cross section of the material. A precise servo driven feed best for a uniform cut and accuracy. Slow feed allows more electrochemical action and lowers cutting forces. Faster feed increases the amount of abrasive action in the cut.

Wheel Type – Apart from standard metal bonded wheels, ECG wheel is also made from Aluminum Oxide on Copper in a conductive resin bond. Diamond, CBN and Ceramic abrasives are also widely used in conductive resin bonds.

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Automatic Electrochemical Flat Grinding Machine

Model: ECHA Uni 501 (source: www.justur.sk)

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1. Machining parts made from difficult-to-cut materials, such as sintered carbides, creep resisting (Inconel, Nimonic) alloys, titanium alloys, and metallic composites.

2. Removal of fatigue cracks from steel structures

3. Production of tungsten carbide tools, fragile parts and thin walled tubes.

Applications of ECG

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Advantages of ECG

1. Absence of work hardening

2. Elimination of grinding burrs

3. Absence of distortion of thin fragile or thermo-

sensitive parts

4. Good surface quality

5. Production of narrow tolerances

6. Longer grinding wheel life (10 times more)

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Disadvantages of ECG

1. High capital cost than conventional machines

2. Process limited to electrically conductive

materials

3. Corrosive nature of electrolyte

4. Requires disposal and filtering of electrolyte

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Electro Chemical Honing (ECH)of internal hole

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Applications of Electro Chemical Honing (ECH)

Removing roundness error

Correcting straightness error

Correcting small taper

ECH effects on bore errors

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Small Hole Drilling Techniques by

Electrochemical Machining

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Small Hole in Fuel Injector Nozzles

Nozzle outlet diameter around 100 micron

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Electro Chemical Drilling

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Deep Hole Drilling by Electro Chemical Action

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At - A - Glance

• In conventional electrochemical drilling hollow metal tube as

cathode

• Electrolyte flows at high velocity

• Cathode penetrates the hole

• Hole diameter Cathode outside diameter

To Drill a small hole – Electrostream drilling

• Application – small cooling hole in super alloys

• Negatively charged acid electrolyte stream with high velocity

• 0.127 mm < Hole diameter < 0.890 mm

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⇒Dwell drilling => Shallow and less accurate holes

• Limited depth of hole

• Work piece configuration or machine capability does not allow nozzle movement

• Maximum depth upto 5 mm

• High applied voltage 150V – 800V

Electro-stream Drilling with Zero feed rate

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Electro-Stream (Capilary) DrillingElectro-stream Drilling with finite feed rate

Drilling inclined holes

⇒Maximum depth 19mm

• H2SO4 /HCl electrolyte

• HCl for Aluminum & Titanium

• H2SO4 for Carbon steel, Cobalt alloy, SS

• Titanium wire is placed inside sleeve

• Individual wire runs in each nozzle

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Advantages of ES Drilling

· High depth-to-diameter ratios are possible

· Many holes can be drilled simultaneously

· Blind and intersecting holes can be machined

· Burr-free holes are produced

· Absence of recast and metallurgical defects

· Powder metallurgy hard materials can be drilled

Electro-Stream (Capilary) Drilling…..

ES Drilling in inaccessible positions

Use of small titanium wire to charge electrolyte

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Thank You

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