Question

1. Why is the required specific energy in grinding much higher than machining process? Explain at least three major reasons and the related assumptions.


2. It is generally recommended that a soft grade grinding wheel be used for hardened steels. Explain why.

Answer 1

1. The reason behind higher specific energy requirment in grinding than machining process are following:

• Machining is process of giving desired shapes to specimen but grinding is process is done to provide good surface finishto already machined part which requirs higher specific energy.
• Machining process uses single point cutting tool in which whole energy is used for shearing the material while removing it but in grinding abrassives are used as cutting tool. Such abrassives have negetive rake angles which leads to increase in cutting force thus requirs more specific energy.
• The material removal rate (MRR) for grinding is much lesser than that achieved in machining. Rubbing and Ploughing also consumes energy without removing material.

2.

Grinding is a process in which abrassives tools are used to provide good surface finish to machined part. A softer tool will deform against the workpiece easily which gives the grinder much more control of tool pressure and tool power than a hard tool, and this ensures the grinder is working a specific area, removing material at a low rate.