By | April 6, 2015

Centreless grinding is a method of grinding external cylindrical, tapered and formed surfaces on workpieces that are not held and rotated between centres or in chucks. There are two types of centreless grinding and they are

  1. External centreless grinding
  2. Internal centreless grinding

External Centreless Grinding

Two wheels – a grinding and a regulating wheel are used in external centreless grinding. Both these wheels are rotated in the same direction. The work is placed upon the work rest and rotated between the wheels. The feed movement of the work along its axis past the grinding wheel is obtained by tilting the regulating wheel at a slight angle from the horizontal. An angular adjustment of 0 to 10 degrees is provided in the machine for this purpose.

centreless grinding

Internal Centreless Grinding

The principle of external centreless grinding is applied to internal centreless grinding also. Grinding is done on the inner surfaces of the holes. In internal centreless grinding, the work is supported by three rolls – a regulating roll, a supporting roll and a pressure roll. The grinding wheel contacts the inside surface of the workpiece directly opposite the regulating roll. The distance between the contours of these two wheels is the wall thickness of the work.

Surface Finishing Processes of Grinding Machine

Internal Centreless Grinding

Advantages of Centreless Grinding

  1. As the workpiece is supported throughout the entire length , grinding is done very
  2. Small, slender and fragile workpieces can be ground
  3. No chucking or mounting of the work on mandrels & other holding devices are
  4. As the process is continuous, it is best adapted for production
  5. The size of the work can easily be
  6. A low order of skill is needed in the operation of the

Diadvantages of Centreless Grinding

  1. In hollow work, there is no certainity that the outer diameter will be concentric with the inside
  2. Works having multiple diameters are not handled

 

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