The substances which are used to decrease the force of friction between the moving parts of machine in contact are known as Lubricants and the process of decreasing the force of friction between the moving parts of machine in contact is known as Lubrication.
When on surface of machinery moves over the another surface, resistance to relative motion of the surfaces arises. When we look at the solid surface it appears smooth to naked eye , but this smooth surface shows irregularities of projections and cavities when viewed under high power microscope.
cavities in surfaces:
When one such surface is placed over another, its projections fall into the cavities of the other and get interlocked .Due to this interlocking , there is resistance to the relative motion of the surfaces. This is called the frictional forces or frictional resistance of friction. In due course of motion, the old projections get broken and deformities arise.
Friction:
Friction may be defined as the opposing force that is set up between the surface of contact, when one body moves over the surface of another body.
When on surface of machinery moves over the another surface, resistance to relative motion of the surfaces arises. When we look at the solid surface it appears smooth to naked eye , but this smooth surface shows irregularities of projections and cavities when viewed under high power microscope.
cavities in surfaces:
When one such surface is placed over another, its projections fall into the cavities of the other and get interlocked .Due to this interlocking , there is resistance to the relative motion of the surfaces. This is called the frictional forces or frictional resistance of friction. In due course of motion, the old projections get broken and deformities arise.
Friction:
Friction may be defined as the opposing force that is set up between the surface of contact, when one body moves over the surface of another body.