Machine failures occur for a variety of reasons. As shown below, the majority of wear-related failures are often lubricant or contamination-related. However, when lubricant failures occur, the question that frequently arises is, “did the lubricant cause the failure or did another condition cause the lubricant to fail leading to equipment failure.” Root cause analysis is often required to provide the answer.
While a typical procedure will vary depending on the nature and severity of the issue, it will primarily consist of four stages:
1. Gathering Preliminary Data
Perhaps the most important step in the process is to preserve and collect clues about the failure. Unless it compromises safety or the quality of information, begin to collect data immediately after the failure occurs – or while the failure is in progress if possible. Make every effort to preserve all data and physical evidence of the failure. The lubricant and lubrication system offer a tremendous amount of information about the failure.
The client should provide the Noria investigator with a packet of relevant information to review. The investigator will review this information prior to making a site visit.
- List of questions for the consultant to address by the end of the project, including immediate and end-of-project needs.
- Synopsis of events including a timeline of the failure(s) and related events
- Lubricant and filter spec information
- Details on the type of machine and operating conditions
- Past used oil analysis reports, if any
- Relevant past data relating to other technologies, e.g. vibration analysis, thermography, proximity probes, acoustics, motor current, etc.
- All root cause failure analysis studies (in-house or by outside consultants)
- Reports from any studies by other labs or consultants, if any
- Reports from the lubricant supplier, equipment supplier, or other vendors relating to the failure, if any
- Photo images of failed parts
- Diagram of the machine showing location of the failed parts and seals
- Related internal correspondence and theories proposed by those familiar with the case
2. Onsite Visit
In some cases, the investigator will make a site visit and spend one day gathering information on the machine of interest, collecting samples and talking with personnel. All parties should be available that day for discussions and to answer any questions the investigator may have on the discovery material provided. Also, during this time, the investigator will discuss recommendations for those needs identified as immediate to stop or slow down any impending failures.
Upon returning to the office, the investigator will take an additional one to two days to digest all the information and submit a brief report of his or her findings, including the most probable root cause(s), additional information needed, a suggested lubricant test slate, if applicable, and a list of open items to complete.
3. Testing & Analysis
If doubt remains about the root cause of the failure, additional investigative steps including testing may be required to narrow down or expand the list of potential root causes. The investigator will recommend an appropriate independent laboratory based on the testing needs.
4. Report Summary
Upon conclusion of the investigation, a final report will be submitted. This will include the following:
- A discussion of findings,
- Possible root causes and most probable root cause,
- Potential tests to run in the future to use as early indicators and,
- Corrective actions/steps needed to avoid similar circumstances.