Table of Contents
What is a lubricant
A lubricant is a substance which is applied between two rubbing surfaces for reducing friction. While dealing with machines, friction among the machine parts can damage it severely.
- Lubrication
Problems caused by friction
- It reduces machine parts life.
- It increases overall power consumption. Because a considerable amount of power is used in overcoming friction.
- Due to friction machine parts create noise and vibration, which is not good for any work place.
- Friction cause overheating of components, due to rubbing.
- Wear and corrosion of machine parts.
Objectives of Lubrication
- To reduce friction forces between moving parts
- To reduce wear and tear of moving parts
- To cool the surfaces heated by the friction between moving parts
- In some cases it is also used to seal the space between adjacent parts
- In some cases it is also used to absorb shocks
- To act as a cleaning agent
Properties of a good lubricant
- It should have suitable viscosity.
- It should act as protective covering against corrosion.
- It should have heavy strength to prevent metal to metal contact under heavy load.
- It should not chemically react with the machine parts.
- It should have low pour point.
- It should not react with air, water and fuel.
- It should have cleaning ability.
- It should be non toxic.
- It should be non inflammable.
- It should have non foaming characteristics.
- Its viscosity should not change with temperature.
- It should ensure the adherence between contacting surfaces.
- Its flash point and fire points should be high.
- It should not form deposits by reacting with the machine parts or the surrounding environment.
- It should have low cost.
Types of lubricants
Basically there are two types of lubricants.
Oil and Grease.
Oil is used where
- Oil are used where a simultaneous cooling is also required.
- Oils are also used for machine parts where greasing is difficult.
- Oils are used for low loads.
- Oils are used for the machines which are using central lubrication systems.
Grease is used where
- Load is high.
- Used for a part of machine (not for whole machine).
- Used for machine parts where frequency of lubrication is low (like bearings).
Image (also featured) attribution: By Audriusa – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7218733