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Explain different types of bonds and abrasives used in a grinding wheel?
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Bonds

It acts as a binder to hold abrasive together.

1.Vitrified Bond

2.Silicate Bond

3.Oxychloride Bond

4.Resinoid Bond

5.Shellac Bond

6.Rubber Bond

1. Vitrified Bond

  • This bond consists of mixture of clay and water.
  • Clay and abrasives are thoroughly mixed with water to make a uniform mixture.
  • The mixture is moulded to shape ofagrinding wheel and dried up to take it out from mould.
  • Perfectly shaped wheel is heated just like brick making.
  • This wheel possesagood strength and porosity to allow high stock removal.
  • Disadvantage of this type of wheel are,it is sensitive for heat,water,oil and acids.
  • Their impact and bending strengths are also low.
  • This bond is denoted by symbol V in specification.

2. Silicate Bond

  • Silicate bonds are made by mixing abrasive particles with silicate and soda or water glass.
  • It is moulded to required shape,allowed to dried up and then taken out of mould.
  • The raw moulded wheel is baked inafurnace at more than 200°C for several days.
    • These wheel exhibits water proofing properly so these can be used with coolant.
    • These wheels are denoted by'S'in specification.

3. Oxychloride Bond

  • These bonds are processed by mixing abrasives with oxides and chlorides of magnesium.
  • The mixture is moulded and baked inafurnace to give shape ofa grinding wheel.
  • These grinding wheels are used for disc grinding operations.
  • An oxychloride bonded wheel is specified the letter O

4. Resinoid Bond

  • These bonds are prepared by mixing abrasives with synthetic resins like backelite and redmanol and other compounds.
  • Mixture is moulded to required shape and baked upto 200°Cto giveaperfect grinding wheel.
  • These wheels have good grinding capacity at higher speed.
  • These are used for precision grinding of cams,rolls and other objects where high precision of surface and dimension influence the performance of operation.
  • Aresinoid bond is denoted by the letter'B'

5. Shellac Bond

  • These are prepared by mixing abrasive with shellac than moulded by rolling Grinding wheels having shellac bond are recommended for cool cutting on hardened steel and thin sections,finishing of chilled iron,cast iron,steel rolls,hardened steel cams and aluminium pistons.
  • This bond is denoted by 'E' in specifications.
SR.
NO.
NAME OF BOND CHARACTERISTICS DESIGNATION
1 Vitrified bond Good strength and high porosity. V
2 Silicate bond Waterproof,used for large
diameter wheels.Grinding of fine
edge tools,etc.
S
3 Shellac bond Thin wheels,high elasticity,not
suitable for heavy duty
application.
E
4 Resinoid bond Rough grinding,high speed
grinding.
B
5 Rubber bond Thin wheels,fine finishing and
polishing e.g. ball bearing races.
R
6 Oxychloride bond Disc grinders,less brittle. O
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