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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 ...
The emphasis of the PDPC is to identify the consequential impact of failure on activity plans, and create appropriate contingency plans to limit risks. Process diagrams and planning tree diagrams are extended by a couple of levels when the PDPC is applied to the bottom level tasks on those diagrams.
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 defect concentration diagram (also problem concentration diagram [1]) is a graphical tool that is useful in analyzing the causes of the product or part defects. [2] It is a drawing of the product (or other item of interest), with all relevant views displayed, onto which the locations and frequencies of various defects are shown.
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.
Control charts are graphical plots used in production control to determine whether quality and manufacturing processes are being controlled under stable conditions. (ISO 7870-1) [1] The hourly status is arranged on the graph, and the occurrence of abnormalities is judged based on the presence of data that differs from the conventional trend or deviates from the control limit line.
DRBFM is implemented based on novelty of change at any level of the product (design, process, supplier, etc.). The intent of the DRBFM is to make these changes visible by discussing them at length, as well as every possible concern for failure that may potentially occur - anything that impacts quality, cost, or delivery.
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.