Electro Stream Drilling (ESD) is an electrochemical machining process that uses a high velocity stream of negatively charged acidic electrolyte to drill small diameter holes. It can drill holes between 0.127-0.89 mm using a voltage of 150-850 V. Unlike conventional electrochemical drilling, debris dissolved in the acidic electrolyte prevents clogging. ESD can drill deep and accurate holes through either dwell drilling or penetration drilling methods and offers advantages like high aspect ratio holes, low surface roughness, and no burrs or residual stresses. However, it has high initial costs and is limited to electrically conductive materials.

1. Electro Stream Drilling(ESD)
(Electrochemical Machining Process)
Shwetank Sahu (R160215095) Suvarna Raghava (R160215101)
Siddharth Thakur (R160215098) Tejveer Singh (R160215104)

2. Electro Stream Drilling Diagram

3. ECD V/S ESD
 In conventional Electrochemical Drilling hollow metal tube is used as cathode.
 Electrolyte flows at high velocity and cathode penetrates the hole.
 Hole Diameter > Cathode Outside Diameter.
 To drill a hole of small diameter ESD can be used.
 High velocity negatively charged acidic electrolyte stream is used in this
process.
 In general ECM process metal hydroxides precipitate as they don’t react with
electrolyte but in ESD they dissolve in electrolyte.

4. Process Principles and Specifications
 This process differs from conventional Electrochemical Drilling.
 High velocity negatively charged electrolyte is used.
 Debris of Metal hydroxides generated in this process is dissolved by acidic
electrolyte.
 Due to dissolving the debris doesn’t clog between inter-electrode gap.
 Therefore, you can generate any type of hole.
 Holes of size 0.127-0.89 mm can be generated.
 Voltage of 150-850 V is applied.
 Nozzle is made of glass.

5. Process Principles and Specifications
 Electro stream of electrolyte with high velocity is flowing through the nozzle.
 Nozzle diameter is made as small as possible.
 Nozzle is given a feed towards the work piece.
 Acidic Electrolyte after impinging on the surface will dissolve it and material
removal will occur
 Exhaust Fan is used to vent out the gas bubbles created during process.
 Electrolyte temperature maintained through the use of heater.
 Filter is used to filter out metallic hydroxide particles from electrolyte.

6. Types of ESD
 Dwell Drilling
 1. Zero feed rate provided
 2. For shallow and less accurate holes
 3. Depth of hole and accuracy limited
 4. Maximum Depth of 5 mm can be achieved
 Penetration Drilling
 1.Deep & accurate drilling
 2. Constant gap maintained using finite feed rate
 3. Constant gap maintained through gap sensing device (Proximity Sensor)
 4. Maximum Depth 19 mm.
 5. Machining rate 1.5mm/min.

7. Types of ESD - Figures

8. Drilling of right angled holes
Drilling hole in cavity:-
Tool with right angle bend
at tip
Length of small diameter
part of tube > depth of
hole
Outside diameter of nozzle
tip:-
Should fit within hole being
drilled, allow room for
repeatable escape of used
electrolyte

9. Charging of Electrolyte
 Use of metallic sleeve or titanium wire placed inside tube
 In multiple nozzle application junction manifold exists where individual wires
run towards each nozzle
H2SO4/HCL --- Electrolyte
HCL for Al,Ti etc.
H2SO4 for carbon steel, cobalt
alloys and stainless steel

10. Process Parameters
 Nozzle Stand off Distance
 Flow of Electrolyte through nozzle
 Type of metal of work piece
 Type of Electrolyte being used
 Temperature and other physical factors of electrolyte

11. Advantages
 Used for drilling high aspect ratio holes (dwell drilling 10:1, penetration drilling 40:1)
 Machining rate 1.5 mm/min
 Special Cases: - 96 holes have been simultaneously drilled in a turbine blade in 15 minutes
 Shallow holes of angle up till 750 from normal to work surface
 Tolerance of up to +/- 5% of hole diameter (but not less than 0.025 mm)
 Surface finish 0.25 – 1.67 micrometre
 Taper can be controlled 0.03 mm/cm
 No Burr generation
 No residual stresses induced
 Insignificant HAZ
 No tool wear

12. Disadvantages
 High initial set up cost
 Can’t be used for drilling large holes
 Electrically conductive materials are necessary as work piece
 Low MRR

13. THANK YOU !