Monday, July 5, 2010

Lubrication..made simple..

The technology of lubrication has been used from the ancient times, from the pyramid building where massive rock slabs are moved, up to present modern times. In machineries, medical application, and leisure. Lubrication means to make something run smooth, make something Slippery, to reduce friction on moving parts. In Tribology, lubricant is consisting of either oil or grease. Most grease is from animal fats or vegetable lard.
An un-lubricated sliding part creates tremendous friction that needs great amount of power to move, slide or separate them. If friction reached the critical level, the heat will fuse the parts and will cause seizure that will ultimately bond the parts or burn them beyond use.
Proper lubrication eliminates the friction that totally contributes to this failure phenomenon. The lubricant stays in between the sliding matter and serves like roller bearings. It continuously reduces the coefficient of friction, thereby reducing the force to move and heat that leads to seizure, bonding and fire. The general purpose of lubrication is to separate the two sliding bodies to reduce friction.

Lubricant in machineries has to stay and maintain the lubricating ability to serve its purpose. This is indicated in the lubricant as drop point for grease and viscosity for oil. Load and working temperature condition are also a major consideration is lubricant selection. Oil and grease comes in basic forms as produced. The additives make the difference as to what lubrication compounds are added to satisfy the end use.

The main purpose of lubrication is to reduce friction and wear in bearings or sliding components to prevent premature failure. The effects of lubrication may be briefly explained as follows:

  • Reduction of Friction and Wear. Direct metallic contact between the bearing rings, rolling elements and cage, which are the basic components of a bearing, is prevented by an oil film that reduces the friction and wear in the contact areas. It prevents inter metallic contacts between slides by allowing film of lubricants preventing friction.
  • Extension of Fatigue Life. The sliding or rolling fatigue life of bearings depends greatly upon the viscosity and film thickness between the rolling contact surfaces. A heavy film thickness prolongs fatigue life, while insufficient film thickness shortens it.
  • Dissipation of Frictional Heat and Cooling. Circulating lubrication may be used to carry away frictional heat or heat transferred from the outside to prevent the bearing from overheating and the oil from deteriorating.
  • Others. Adequate lubrication also helps to prevent foreign material from entering the bearings and guards against corrosion and rusting. Satisfactory bearing performance can be achieved by adopting the lubricating method that is most suitable for the particular application and operating conditions. In general, oil offers superior lubrication; however, grease lubrication allows a simpler structure around the bearings.











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