(Part 1 is available here)

The best way to ensure the longevity of machines is to take a proactive approach to their maintenance. Lubrication plays an essential roll in making sure these tools are operating at their best, but because there are so many different components to these machines, there are a variety of different failure modes on account of lubrication and lubrication programmes.

Taking proactive measures to ensure that lube is performing its best can go a long way in extending the lifespan of a machine. In fact, the proper failure mode prevention programme can make a machine last three to eight times longer. For this reason it is important to take note of all the failure modes of lubrication and lubrication programmes.

Part 1 of this series covered the temperature and moisture failure modes. This instalment of the series will cover foreign materials and particles, viscosity and contamination.

Foreign Materials and Particles

Foreign materials and particles can be a major source of failure mode. The film between a loaded bearing, or gear is only about 5 microns. Foreign particles on the other hand can be as large as 40 microns. This means that when these particles get into machine lube, they can grind and scratch the bearings and gears of the machine.

Contaminates can get into lubrication for a number of reasons. Poor storage methods can be one major reason. Other contributors, depending on the facility, could include particles that are simply floating around in the plant getting into the lube.

In addition, the way new lube is handled can allow foreign materials to enter. Even new oil can be contaminated and, if the filtration is not adequate, particles from new grease can lead to lubrication failure modes. Further, lubricationrelated failures can arise if lube filtration is improperly handled, or the grease can become contaminated simply out of long-term machine wear and tear.

The ISO code for cleanliness outlines a method for measuring the amount of foreign particles in lube, and the effects that these materials can have on a machine. The code has three numbers separated by a ‘/’ with each number representing the amount and size of particles. The first number in the code is the amount of 4-micron particles, the next number is 6-micron particles and the third is for 14-micron particles.

Take a 21/19/15 on the ISO code. A 21 means that there are between 10,000 and 20,000 particles at 4 microns in size, the 19 means there are between 2,500 and 5,000 particles at 6 microns and between 160 and 320 microns at 14 microns, all within a one millilitre sample. By reducing these figures with cleaner oil, the life of a gearbox can be extended. For instance, by reducing a 21/18/16 to a 19/12/9 the life span of a gearbox can increase by 2.5 times. Depending on the level of reduction, these life extensions can increase by up to seven or eight times.

In order to achieve these strong ISO codes, it is vital to eliminate particles from lubricants, filter new oils, keep lubes clean before and during the use of equipment and purchase grease products that have been produced with filtered oil or make the switch to synthetics.

Viscosity Is Important

Viscosity failure modes can occur for a variety of reasons. Fluctuations in temperature can lead to changes in viscosity, while oxidation, contamination, moisture and chemicals can each contribute to changes as well. Further, not enough or no additives will contribute to changes in viscosity along with other lube procedures.

Viscosity is what determines how the lube will flow through a machine. Different machines call for different viscosity levels. It is important to understand the operating temperature of the machines, as it can change between standby and when the machine is running. Failure to achieve the right viscosity as it relates to machine operation can lead to leaks and other forms of failure. It is important to understand that greases can fluctuate in viscosity as well.

As previously mentioned contamination that leads to changes in viscosity can arise due to ambient conditions such as temperature, humidity and free floating particles in the plant in which it is used. Other contributions to contamination can be: improper practices in lube storage, application, transportation, equipment, procedures and leaking coils. In addition, contamination from the vendor must also be considered. To address these issues it is important to have a well-constructed lube storage facility that can control temperature and other factors for proper receiving, storage and distribution of lubricants. Also, make sure to always check for contaminants, filter new oils, use oil safe containers, install labyrinth seals on critical equipment, and obtain the proper training on eliminating contaminants.

Keep in mind that synthetic lubes outperform mineral oil-based lubricants in almost every situation. This is because they are much more stable when it comes to temperature, oxidation and volatility, while having longer life spans. They also have less foaming characteristics and changes of hydrolysis.

Operational Failures

Operational failures are largely a result of bad maintenance. Improper oil levels and incorrect oil addition along with sudden volume loss can lead to operational failures. Using the wrong oil or additives, foaming, particles, moisture along with under or over greasing and improper wash down practices also contribute to operational failures.

These failure modes arise largely from improper maintenance and operations, meaning that a strong knowledge of how machines work and how to apply lube is the best defence against them.

Programme Failures

Lubrication excellence programmes are essential to preventing lubrication failures and extending the life of machines. Many of these failures covered here can be the product of a lack of knowledge, best practice and maintenance, all of which can be prevented with a strong programme.

Programme failure modes can arise from an incomplete or non-existent programme or a lack of documentation. Ordering, receiving and storing also need to be an integral part of any programme, along with an RCM decision process. Also, filtration systems that are both on and offline are essential, as is proper equipment for draining oil. Be sure to maintain proper additive packages and better analysis programmes.

Ultrasonic lubrication equipment can also play an important role in monitoring lube levels and possible failures. These are not all the programme failures, but generally speaking, a sound training programme and documented procedures provide workers with the knowledge they need to make sure that machines will be able to last. Lubrication Excellence training can teach workers about the correct methods to eliminate failure modes, which, if properly addressed, can extended equipment life by 3 to 8 times.

At the end of the day, proper lubrication maintenance and failure prevention is about taking a proactive approach, so by equipping workers with the proper tools and knowledge plants can significantly extend the life of their machines.

Terry Harris CMRP,

President, Reliable Process Solutions, on behalf of UE Systems, Inc,

tkharris10@hotmail.com