Choosing the Right Lubricant Viscosity

Lubrications come in a wide variety of viscosity. Choosing the right one may be a daunting task and there are plenty of key details you will need to know before making your purchase. Your lubricant decision will have a large impact on the performance of the machinery it is applied to and in some cases, its lifespan as well.

Industrial lubricants have certain temperatures where they work at their optimum. When below or above said temperatures, lubricant consumption increases and it will deplete faster than advertised. An example is an ISO VG 150 viscosity lubricant that has a flash point of above 200 degrees C. This would allow the user to easily apply the lubricant to a machine that operated at 125 degrees C without any worry of lubrication loss. In the event that the appropriate lubricant has been chosen and the system continues to be faulty, it is advised to inspect the machine as it may have leaks from various other components. Certain machines may exceed operating temperatures causing various other reactions and it will affect the lubricants viscosity. 

As mentioned above, to pick the right lubricant technical details of the machine will be needed. Details such as bearing conditions, operating temperature, speed, subjected load, bearing design and application method. Cross checking these details with the range of lubricant specifications will make your decision making process much simpler. 

A common solution for “misbehaving” machinery is to increase the viscosity grade by one class above. This is a simple solution to keep any leaking or evaporation at bay before dealing with the larger issue of the machine itself. For example, a paper machine is using  ISO VG 150 lubricant but has developed evaporation of lubricant. It will be safe to increase to one grade higher, the ISO VG 220 without compromising lubrication quality.

If the machine being used has a sump, the sump size must be calculated based on the system capacity and maximum pump flow rate. In a sump system, the lubricant must stay in the sump for at latest 5 to 10 minutes. The calculations are important to maintain a minimum volume in it for table oil supply. The lubricant stays in the sump for that extra time to allow contaminants, release of foam and heat loss to occur safely. 

Machine maintenance coincides with lubrication choice. If the machine has been expanded with more components, it is important to reevaluate the new working conditions. Be sure to monitor vital levels such as oil and temperatures during operating as well as after to meet the new optimum performing conditions. 

Switching to synthetic lubricants can offer a great advantage to efficiency and oil consumption. If the machine is having a problem, switching to synthetics is a possible solution to explore and monitor but may not be a guaranteed root problem solver. The best solution is to identify the cause of lubricant consumption and take appropriate action.