Improving Equipment Reliability

A failed component is not only expensive when considering repair costs, downtime and lost productivity, but it’s also an inconvenience. Too often repairs only consist of replacing the component without further investigation into what may be the root of the problem.

Debris particle contamination in lubricants has been identified as a major cause of premature equipment and component failure. Not only can contamination in a lubrication system cause these types of issues, but neglecting to run proper checks of the lubrication system can mean the problem goes uncorrected, leading to continued damage, more premature failures and diminished equipment performance.

Controlling and preventing this contamination is not an easy task, and don’t be misled by what you can’t see. Debris can be small enough to measure in microns, and can enter the system at any time, including at the assembly phase or later while performing maintenance. Debris contamination can also be a by-product of the environment, as it’s introduced to the system anywhere lubricant is exposed to surfaces that rub or rotate together.

Contamination can continue to cause damage throughout a variety of areas. By reducing the surface durability and resistance to fatigue, solid contaminants make themselves known through abrasive wear, denting/bruising, grooving and fatigue spalling.

Analysis Tools
Various experimental and predictive methods have been developed to assist in the analysis and development of equipment that is less sensitive to contamination. In regards to contamination characterization, today’s equipment designers have a broad selection of analysis tools to help them assess the detrimental effects of debris particles on machinery durability and performance.

Some of these include wear particle and contamination analysis methods like Ferrographic, Gravimetric Filtration, Atomic Absorption Spectroscopy and SEM (EDAX) Spectroscopy, all of which are aimed at understanding the material make-up and characteristics of the contamination. In addition, particle size distributions and concentration levels are sought by particle sizing and counting techniques. Such techniques employ both manual microscopic approaches as well as automatic direct counting through equipment using light scattering methods.

Another option is a contaminated lubrication analysis. Comprehensive lubrication analysis programs monitor the physical properties of the lubrication, contamination levels and wear debris over time. If samples of oil, or in some cases grease, are taken on a regular basis, physical and chemical testing will help gauge how well the system is running. Properly implemented, such a program can provide early warning of problems before they get too serious.

A more direct method, using surface damage characterization, has been developed for quantifying the effect of debris-contaminated lubrication environments on predicted life. Appropriately labeled as Debris Signature Analysis, this approach establishes a life prediction model based on understanding the relationship between particle material, size, shape, hardness or fracture toughness, and damage on the contacting surface.

Performed during routine maintenance tear downs, Debris Signature Analysis provides a direct and practical approach to determining the severity through characterizing damaged surface topography. The contamination factor is then calculated and used in decreasing the predicted life under contaminated conditions. The key to this is being able to characterize damage on the components’ surfaces and link it directly to performance.

Prevention Improvement
Although analysis tools provide a clearer understanding of system contamination and damage, it is difficult to completely eliminate debris from the system. Instead, efforts should be focused on minimizing and combating contamination. Two areas that provide alternative solutions for debris include non-bearing solutions and debris-resistant products.

First and foremost, proper care of components is vital in order to reduce contamination. Proper storage, cleaning and inspection of equipment are simple examples, but efforts to minimize contamination can also include:
• Simply cleaning the lubrication system.
• Applying a filtration system.
• Enhancing the sealing systems.
• Inspecting any re-used components for debris damage.

Each step taken to prevent and combat debris highlights an improved understanding of the contamination and its effects on the reliability of equipment. Detrimental to productivity and the bottom line, debris demands the attention of machine operators.