Electrochemical grinding: Difference between revisions
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==Uses== |
==Uses== |
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*Production of [[tungsten]] carbide cutting tools.<ref name=McGeough /> |
*Production of [[tungsten]] carbide cutting tools.<ref name=McGeough /> |
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*Burr-free sharpening of [[hypodermic needle|hypodermic needles]] |
*Burr-free sharpening of [[hypodermic needle|hypodermic needles]]<ref>Valenti, "Making the Cut."</ref> |
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*Grinding of [[superalloy]] turbine blades |
*Grinding of [[superalloy]] turbine blades |
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*Form grinding of aerospace [[Composite honeycomb|honeycomb metals]] |
*Form grinding of aerospace [[Composite honeycomb|honeycomb metals]] |
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Revision as of 18:10, 23 February 2010
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.[1] Materials removed from the workpiece stay in the electrolyte fluid. Electrochemical grinding and electrochemical machining are similar but a wheel is used instead of a tool shaped like the contour of the workpiece.
Process characteristics
- 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.[2]
- Capable of producing smooth edges without the burrs caused by mechanical grinding.[3]
- Does not produce appreciable heat that would distort workpiece.[4]
- Decomposes the workpiece and deposits them into the electrolyte solution. The most common electrolytes are sodium chloride and sodium nitrate at concentrations of 2 lbs per gallon.[1]
Process schematics
The wheels are metal disks embedded with abrasive particles. Copper, brass, and nickel are the most commonly used materials; aluminum oxide is typically used as an abrasive when grinding steel. A thin layer of diamond particles will be used when grinding carbines or steels harder than Rockwell C65.
Tolerance
- This kind of grinding is mostly used because it can shape very hard metals and also because it is a chemical reducing process, the wheel lasts a longer time than normal grinding wheel can.
- This type of grinding has different types of wheels so it can shape metals to whatever they need to be shaped to.
- Produces a smoother, burr-free surface and causes less surface stress than other grinding methods.
Uses
- Production of tungsten carbide cutting tools.[5]
- Burr-free sharpening of hypodermic needles[6]
- Grinding of superalloy turbine blades
- Form grinding of aerospace honeycomb metals
- 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.[5]
Disadvantages
Electrochemical grinding loses accuracy when grinding inside corners, due to the effects of the electric field.[5]
References
- ^ a b Nontraditional manufacturing processes: Volume 19 of Manufacturing engineering and materials processing, CRC Press, 1987, pp. 153–160, ISBN 0824773527
{{citation}}:|first=missing|last=(help); Missing pipe in:|first=(help) - ^ Industrial electrochemistry, Springer, 1990, pp. 464–466, ISBN 0412304104
{{citation}}: Unknown parameter|authors=ignored (help) - ^ Valenti, Michael, "Making the Cut," Mechanical Engineering, American Society of Mechanical Engineers, 2001. http://www.memagazine.org/backissues/membersonly/nov01/features/makcut/makcut.html, accessed 2/23/2010
- ^ Valenti, "Making the Cut."
- ^ a b c McGeough, J. A. (1988), Advanced methods of machining, Springer, p. 82, ISBN 0412319705
- ^ Valenti, "Making the Cut."