BSides Seattle 2024 - Stopping Ethan Hunt From Taking Your Data.pptx
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Electrochemical machining by Himanshu Vaid
1.
2. Introduction
๏ Non-conventional machining system in which metal is
removed by electrochemical process
๏ Characterized as โReverse Electroplatingโ means it
removes metal instead of adding it
๏ Normally used for mass production and for hard
materials that are difficult to machine using
conventional processes
๏ Both external and internal geometries can be
machined
3. Principle
๏ Faradayโs law of electrolysis :
The Weight of the substance produced during
electrolysis process is directly proportional to
1. the current which passes
2.the length of time of process
3.The equivalent weight of the material
๏ Two dissimilar metals are in contact with an electrolyte
and anode loses metal to cathode
7. Main subsytem
๏ Power Supply
๏ Electrolyte
๏ Tool
๏ The Control system
๏ The machine
8. Power Supply
๏ Available in sizes upto 10,000 amp (some circuits are
available upto 40,000amp)
๏ Range of voltage โ 2 to 30 volts d.c.
๏ A constant voltage has to be maintained and high
density is required
9.
10. Electrolyte
๏ Essential for electrolytic process
๏ It cools the cutting zone which becomes hot due to the
flow of high current
๏ Neutral salts are used as electrolyte in place of highly
corrosive acids and alkalies
๏ Electrolyte solution is pumped between the
tool/workpiece gap at about 2.5 N/mm2 and 30 m/s
11. Tool
๏ Requirements of Tool For ECM :
๏ Good thermal conductivity
๏ Strong enough to withstand high pressures
๏ It should be easily machined
โขMaterial for tool : Copper,brass or stainless steel
โขOuter insulation material : Vinyl, Teflon, epoxy,
enables or high temperature varnish
12. The control system
๏ Control Parameters include
๏ Voltage
๏ Inlet and outlet pressure of electrolyte
๏ Temperature of electrolyte
โขThe current is dependent on above parameters
and feed rate
15. STEM
Figure The shaped-tube electrolytic
machining (STEM) cell process is a
specialized ECM technique for drilling
small holes using a metal tube electrode
or metal tube electrode with dielectric
coating.
19. Further specialized Applications
๏ Die Sinking
๏ Profiling and contouring
๏ Trepanning
๏ Grinding
๏ Drilling
๏ Micro-machining
๏ Pulsed ECM
20.
21.
22. Economics & Products
๏ The process is economical when a large no. of complex
identical products are to be made
๏ Large cavities are more economical on ECM and can be
made in 1/10th time in EDM
๏ Two most common products :
๏ Turbine/compressor blades
๏ Rifle barrels
โขStress free grooves
โขAny groove geometry
โขAny conductive metal can be
machined
โขRepeatable accuracy of 0.0005โ
โขHigh surface finish
โขFast cycle time
Important characteristics that can be achieved are :
23. ๏ ECM is well suited for the
machining of complex
two-dimensional shapes
๏ Delicate parts may be
made
๏ Difficult-to machine
geometries
๏ Poorly machinable
materials may be
processed
๏ Little or no tool wear
๏ Initial tooling can be
timely and costly
๏ Environmentally
harmful by-products
๏ Complicated tool
design
๏ Large power
consumption
Advantages Disadvantages
Die sinking is a process used to machine or create a specific size or shape cavity or opening in steel blocks.
Most often, die sinking is used to place names, numbers, and other sources of information onto metal