부산대학교 도서관

Complex field warranty or other product problems often go unresolved or take too long to be resolved. Examples of such problems include those with insufficient evidence available to physically identify the root cause(s) such as burned or electrically overstressed components. Additionally, complex problems can include those problems that have many potential root causes where for various reasons the actual root cause(s) are not easily identifiable. Such problems can benefit from the synergic application of reliability engineering methods such as Life Data Analysis (LDA), Design Review Based on Failure Modes (DRBFM), and Fault Tree Analysis (FTA) to analyze, describe and visualize the problem and its potential root causes in a systematic and logical manner that effectively orchestrates cross-functional parallel execution of an action plan to more quickly solve the problem.Conducting a LDA with warranty failure data helps to analyze and describe the problem in a quantified manner so that the extent of the problem is well understood in terms of failure symptoms or issues, age, failure rate, and other relevant parameters. A DRBFM study helps analyze specific issues identified through a LDA in a systematic manner to identify the potential root causes and associated risks. This systematic manner of focusing on specific functions, failure modes and concerns associated with the failed component, also assists in the determination of design, testing, manufacturing, and supplier related actions that need to be taken to verify and address the actual root causes. An FTA helps in ensuring that the action plan developed through the DRBFM study is executed in an optimized manner through effective visualization of the potential root causes and their logical inter-relationships that leads to the field failure symptoms of concern. Furthermore, the synergic application of FTA and DRBFM assists in identifying opportunities for parallel execution of action plans within and between disciplines such as related to manufacturing and product design.Considerations should be given to putting fixes in place for all remaining root causes after DRBFM actions plan has been executed and residual risk reassessments have been made. Total cost of implementing solutions to fix a problem versus the total cost of not solving the problem needs to be considered. The effectiveness of a potential solution to fix a problem can be assessed through Reliability Demonstration Testing (RDT). The effectiveness of actual improvements made on a product can be evaluated by analyzing new field data using analytic methods such as unreliability projection curves.