The Practical Guide to Oil Analysis

As a predictive maintenance tool, oil analysis is used to uncover, isolate and offer solutions for abnormal lubricant and machine conditions. These abnormalities, if left unchecked, usually result in extensive, sometimes catastrophic damage causing lost production, extensive repair costs, and even operator accidents.

The goal of a world-class oil analysis program is to increase the reliability and availability of your machinery, while minimizing maintenance costs associated with oil changeouts, labor, repairs and downtime. Accomplishing your goal takes time, training and patience. However, the results are dramatic and the documented savings in cost avoidance are significant.

What are Lubricants

Industrial oils are specifically designed fluids composed of a base oil and a compliment of additives. The base oil performs these functions, including forms a fluid film between moving parts in order to reduce friction and wear; carries away contaminants to the filter; and removes heat generated within the machine. Additives are chemical components added to the base oil to significantly enhance the performance characteristics of the lubricating oil. Typical enhanced properties include oxidation stability, wear protection, and corrosion inhibition.

Why Analyze Used Lubricants

There are three aspects of oil analysis, contaminants, lubricant conditions and machine wear. Ingressed contaminants from the surrounding environment in the form of air, dirt, water and process contamination are the leading cause of machine degradation and failure. Increased contamination alerts you to take action in order to save the oil and avoid unnecessary machine wear.

The assessment of the lubricant condition reveals whether the system fluid is healthy and fit for further service, or is ready for a change. Lastly, an unhealthy machine generates wear particles at an exponential rate. The detection and analysis of these particles assist in making critical maintenance decisions. Machine failure due to worn out components can be avoided. Remember, healthy and clean oil lead to the minimization of machine wear.

How Lube Oils Fail

Typically lubricant oils fail as a result of contamination, oil degradation and additive depletion. Contamination is usually caused by external sources like dirt, water, and process related liquids or materials or internal sources like machine wear and degradation by-products. Lubricant oils also fail because of oil degradation, or oxidation. It is where atmospheric oxygen combines with hydrocarbon molecules. The hotter the oil and the greater exposure to air, the faster oxidation proceeds. The initial by-products of oxidation are sludges and varnishes. However, further oxidation converts these by-products into carboxylic acids. These acids then aggressively attack and corrode many machine component surfaces. In addition, lube oils fail because of additive depletion, which are consumed or chemically changed while performing their function. The performance characteristics of the lubricant are altered and the enhanced properties are wiped out.

What Oil Analysis Measures

Oil analysis measures the physical and chemical properties of the oil, contamination and mechanical wear. You can uncover contamination or degradation by trending rates of change in selected lube properties, such as viscosity, acid number, particle counting, fourier transform infrared (FT-IR) and Karl Fischer water. Oil analysis also measures mechanical wear, which uncovers machine related problems using ICP spectroscopy, wear particle concentration, and analytical ferrography.