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Machinery & Equipment MRO
Q U I Z December 2021
THE ESTABLISHMENT OF AN EFFECTIVE FAILURE ANALYSIS PROGRAM
Failure analysis programs are in place at production and manufacturing plants in many industries, but they tend to stop at a certain stage. BY L. (TEX) LEUGNER What are the most common types of failures in your particular facility? LOGIC: There are several very common types of failures, they include overload or over-speed (a common result of a latent cause); fatigue, of bearings for example, which can be considered normal if the bearing has reached the end of its life cycle; corrosion, causing material loss in a component; elevated temperatures, resulting in lubrication failure or changes in the metallurgical condition of the component. What methodology of failure analysis is used in your facility? LOGIC: There are six typical steps recommended in the failure analysis process. First is “diagnosis”: inspect the component carefully, using high magnification photos to determine if the failure is one of those frequently occurring, such as corrosion, temperature, lubrication related or fatigue. Next, “collect background data”: frequently failures are a direct result of an inadequate repair just completed and review the machines complete maintenance history in detail. Then “inspect the component (or pieces of it)” with a good quality microscope, develop a logic tree and list every symptom of the failure. Now “complete a detailed chemical, scanning electron microscopy or metallurgical analysis” to determine the related condition of the component or its pieces. Then “determine
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hese programs are in place to determine and understand the root causes of component and machine failure, avoid recurrence, reduce costs, and improve equipment reliability. Unfortunately, and frequently, the root cause failure analysis process stops at the identification of the physical causes of a component or machine failure. Root causes can be categorized into physical, human, and latent (organizational and managerial) causes. When the failure analysis team stops at uncovering the physical causes, a complete picture of why the failure occurred in the first place has not been fully investigated and determined. Delving into greater depths to identify human or latent causes of failure allows one to recognize incorrect or inadequate human actions, or inappropriate corporate policies that unknowingly or unintentionally permit the wrong or inappropriate human actions to occur. A common example of human causes is lack of training in many maintenance or operational functions. A latent and very common cause of failure is a philosophy among some plant executives and managers that maintenance is a cost rather than an investment, which creates mistakes because the deference of scheduled PM tasks, in favour of production results in unexpected stoppages or failure.
