Case Study: Root Cause on Seal Failure in Refinery

To understand why a part or equipment failed, how it failed must be first diagnosed. Different failure modes such as fatigue, brittle, and corrosion all have very different causes and very different solutions. If an investigation were to guess at the failure mode and guess wrongly, the planned remediation may not address the true cause of failure and additional failures may occur. This article considers three failed chain links and demonstrates the importance of identifying how something failed.

Semiconductor devices are almost always part of a larger, more complex piece of electronic equipment. These devices operate in concert with other circuit elements and are subject to system, subsystem and environmental influences. When equipment fails in the field or on the shop floor, technicians usually begin their evaluations with the unit's smallest, most easily replaceable module or subsystem. The subsystem is then sent to a lab, where technicians troubleshoot the problem to an individual component, which is then removed--often with less-than-controlled thermal, mechanical and electrical stresses--and submitted to a laboratory for analysis. Although this isn't the optimal failure analysis path, it is generally what actually happens.

With RCFA being a buzzword of the 90’s, companies are faced with a slew of new vendors with numerous RCFA methods and practices to help you attain quantum results. How do you decide who is going to make you money versus who is going to take your money?

This paper presents an overview of an integrated process for system maintenance, fault diagnosis and support. The solution is based on Qualtech System, Inc.’s (QSI’s) TEAMS toolset for integrated diagnostics and involves several key innovations. As a showcase of the integrated solution, QSI, along with Antech Systems and Carnegie Mellon University (CMU), have recently completed a research project for the Information Technology Branch at the Naval Air Warfare Center–Aircraft Division (NAWC-AD) in St. Inigoes, MD. The entire system, termed ADAPTS (Adaptive Diagnostic And Personalized Technical Support), provides a comprehensive solution to integrated maintenance and training.

I was asked recently to give a second opinion on the cause of failure of an axial piston pump. The hydraulic pump had failed after a short period in service and my client had pursued a warranty claim with the manufacturer. The manufacturer rejected the warranty claim on the basis that the failure had been caused by contamination of the hydraulic fluid. The foundation for this assessment was scoring damage to the valve plate.

Root Cause Analysis (RCA) is a valuable tool for reliability improvement in manufacturing and production operations. Yet, most efforts to implement an RCA program fail to achieve meaningful results despite significant investments in employee training. What needs to be done to assure that RCA becomes a functional work process in organizations?

Fatigue is a failure mode that every manufacturing plant will experience at some point and can become chronic if not solved. While understanding fatigue has advanced since its inception in the early 1800s, there are still some misunderstandings in manufacturing in solving these failures. A characteristic of fatigue failures is stress, which is typically below the yield strength of the material. This is what makes fatigue a silent killer.