Selecting grinding wheels

For maximum efficiency in any grinding operation, it is essential to have the right wheel for the job. Factors to be considered when selecting a grinding wheel:                                                                 

1. Workpiece                                                   

Type andhardnessof the material: theharder the material, the softer the grade of wheel required.                           

Aluminum Oxide: most efficient for grinding high-tensile materials such as steel and ferrous castings. The more friable types of alumina are preferred for use on harder steels.                                                           

Silicon Carbide: for materials with low tensile strength, and non-metallic materials.

2. Stock removal 

The amount of stock to be removed  affects the choice of grain size and bond type:

-a coarse grit (14-30mesh) is suitable for high stock removal rate.

-fine grits are best for fine finishes and low tolerances.

3. Surface finishing 

High surface finish is achieved using a fine grit. The best quality surface finish also requires, in addition to a fine grit, an organic bond such as resin or rubber.

4. Grinding machine

-The power available defines the rate of stock removal. The greater the power available, the harder the grade of wheel required for efficient operation.  

-Deterioration in machine condition leads to vibration and early breakdown of the wheel.

5. Speeds in cylindrical grinding 

The rotating speed of the wheel, the rotating speed of the workpiece, and the plunge feed rate/ 

traverse feed rate - all affect the choice of wheel. The influence of these factors on the grinding 

process can be described as follows: 

1). wheel speed increases ---wheel acts harder 

  wheel speed decreases---wheel acts softer 

2). workpiece speed increases ---wheel acts harder 

  workpiece speed decreases ---wheel acts softer 

3). speed of progress increases ---wheel acts harder (temperature rises) 

  speed of progress decreases ---wheel acts softer (temperature decreases)