Downloaded 126 times
More Related Content
Similar to Electro stream drilling(ESD)
Electro stream drilling(ESD)
- 1. Electro Stream Drilling(ESD) (ElectrochemicalMachining Process) Shwetank Sahu (R160215095) Suvarna Raghava (R160215101) Siddharth Thakur (R160215098) Tejveer Singh (R160215104)
- 2. Electro Stream DrillingDiagram
- 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 andSpecifications 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 andSpecifications 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 rightangled 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 NozzleStand 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 fordrilling 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 initialset up cost Can’t be used for drilling large holes Electrically conductive materials are necessary as work piece Low MRR
- 13.