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A PFMEA will focus on process failure modes (such as inserting the wrong drill bit). Failure cause and/or mechanism Defects in requirements, design, process, quality control, handling or part application, which are the underlying cause or sequence of causes that initiate a process (mechanism) that leads to a failure mode over a certain time.
The FRACAS process is a closed loop with the following steps: Failure Reporting (FR). The failures and the faults related to a system, a piece of equipment, a piece of software or a process are formally reported through a standard form (Defect Report, Failure Report). Analysis (A). Perform analysis in order to identify the root cause of failure.
The design or process controls in a FMEA can be used in verifying the root cause and Permanent Corrective Action in an 8D. The FMEA and 8D should reconcile each failure and cause by cross documenting failure modes, problem statements and possible causes. Each FMEA can be used as a database of possible causes of failure as an 8D is developed.
A fault tree diagram. Fault tree analysis (FTA) is a type of failure analysis in which an undesired state of a system is examined. This analysis method is mainly used in safety engineering and reliability engineering to understand how systems can fail, to identify the best ways to reduce risk and to determine (or get a feeling for) event rates of a safety accident or a particular system level ...
Sample Ishikawa diagram shows the causes contributing to problem. The defect, or the problem to be solved, [1] is shown as the fish's head, facing to the right, with the causes extending to the left as fishbones; the ribs branch off the backbone for major causes, with sub-branches for root-causes, to as many levels as required.
The first piece of information added in an FMEDA is the quantitative failure data (failure rates and the distribution of failure modes) for all components being analyzed. The second piece of information added to an FMEDA is the probability of the system or subsystem to detect internal failures via automatic on-line diagnostics.
The software development process is a typical application of Fagan inspection. As the costs to remedy a defect are up to 10 to 100 times less in the early operations compared to fixing a defect in the maintenance phase, [1] it is essential to find defects as close to the point of insertion as possible.
In model-based FDI techniques some model of the system is used to decide about the occurrence of fault. The system model may be mathematical or knowledge based. Some of the model-based FDI techniques include [2] observer-based approach, parity-space approach, and parameter identification based methods. There is another trend of model-based FDI ...