electrochemical grinding

ELECTROCHEMICAL GRINDING

1. BIRLA VISHVAKARMA MAHAVIDYALAYA TOPIC: ECG – Electro Chemical Grinding Guided by: PROF. A H JARIYA Presented By: SR.NO. ENROLLMENT NO. NAME 1 140080125002 ULLAS BHALANI 2 140070125028 VRAJ SHAH SUBJECT: ALLIED MANUFACTURING TECHNOLOGY (2162507)

2. Why non traditional process required?? Unconventional manufacturing processes is defined as a group of processes that remove excess material by various techniques involving mechanical, thermal, electrical or chemical energy or combinations of these energies but do not use a sharp cutting tools as it needs to be used for traditional manufacturing processes. Extremely hard and brittle materials are difficult to machine by traditional machining processes such as turning, drilling, shaping and milling.

3. Several types of non-traditional machining processes have been developed to meet extra required machining conditions. When these processes are employed properly, they offer many advantages over non-traditional machining processe s Unconventional process is employed where traditional machining processes are not feasible, satisfactory or economical due to special reasons as discussed below…. Very hard fragile materials difficult to clamp for traditional machining When the workpiece is too flexible or slender When the shape of the part is too complex

4. What is ECG?? Electrochemical grinding  is a process that removes electrically conductive material by grinding with a negatively charged  abrasive grinding wheel, an electrolyte fluid, and a positively charged workpiece . Materials removed from the workpiece stay in the electrolyte fluid. Electrochemical grinding is similar to electrochemical machining but uses a wheel instead of a tool shaped like the contour of the workpiece.

5. In this process the abrasive lead and grinding field is connected to cathode and the work piece is connected to the anode

6. What Process characteristics required?? The wheels and workpiece are electrically conductive. Wheels used last for many grindings - typically 90% of the metal is removed by  electrolysis and 10% from the abrasive grinding wheel . Capable of producing smooth edges without the burrs caused by mechanical grinding . Does not produce appreciable heat that would distort workpiece . Decomposes the workpiece and deposits them into the electrolyte solution.

7. Process parameters governing MRR Type of abrasive, grain size, grain concentration, profile of the grinding wheel and bonding material used.  Shape of work material, pre-treatment process involved and surface topography and  Machining conditions such as feed rate, wheel speed, depth of cut etc. Input voltage across the two electrodes Equivalence of atomic weight and valency of elements of work material Conductivity and strength of electrolyte  Gap width Degree of polarization

8. Advantages C an grind thin material of 1.02 mm, which normally warp by the heat and pressure of the conventional grinding Burr free No work hardening Stress free Better finish No cracking Less frequent wheel dressing No metallurgical damage from heat Faster for tough materials No wheel loading or glazing More precise tolerances up to 0.025mm

9. Limitations B oth the work piece and the grinding wheel must be conductive . It is only applicable to surface grinding. The electrolytic fluid can cause corrosion at the work piece and grinding wheel surfaces. M ore complicated than traditional machining methods. H igher production cost.

10. Applications Grinding turbine blades Grinding honeycomb metals for aerospace application Sharpening hypodermic needles Machining carbide cutting-tool inserts ECG is used to remove surface defects from parts where excessive material removal and residual stresses are undesired, such as re-profiling locomotive gears Removal of fatigue cracks from underwater steel structures. In this case, seawater itself acts as the electrolyte. Diamond particles in the grinding wheel remove any non-conducting organic matter, such as algae, before electrochemical grinding begins .