Causes (Failure Modes)

In an FMEA or RCM, the causes (typically called failure modes in RCM analysis) state the specific reason for the failure, preferably found by asking "why" until the root cause is determined.

To access the commands to add or edit cause records, right-click inside the FMEA hierarchy or worksheet, or use the Causes commands on the FMEA tab of the ribbon. (See FMEA Tab for a complete list.)

As discussed in Choosing the FMEA Structure, the FMEA Structure field on the General page of the Project Properties determines how the effect and cause records will be displayed in the FMEA hierarchy.

  • Causes Before Effects or Grouped Effects and Causes - each cause will be associated with a failure record.
  • Effects Before Causes - the cause will be associated with an effect record.

The properties enabled (and their display names) will depend on the interface style for the current project. To view or change these settings, choose Project > Management > Configurable Settings > Interface Style.

Note the following:

  • The Description is required.

  • The Name will be used in locations where the full description would be too long to display (e.g., diagrams). If the field contains an asterisk (*) or is blank when you save the record, the software automatically uses the first 50 characters of the full description.

  • The #, ID, Source Record, Associated Records, History and ribbon commands are similar for any FMEA record type. (See FMEA Records.)

  • Use Classification to identify design characteristics that require special manufacturing control (e.g., Critical, Significant, Key Leading, etc.).
  • The options in the following drop-down lists are based on the rating scales that have been assigned in the configurable settings for the current project. The RPN will be calculated automatically if you have defined a Severity rating for the effect, and Occurrence and Detection ratings for the cause. (The drop-down lists work just like the Find panel found elsewhere in the software.)
    • The Initial Occurrence and Revised Occurrence ratings estimate the probability of occurrence for the potential failure cause.
    • The Initial Detection and Revised Detection ratings estimate the probability that the problem will be detected before it reaches the customer or end user.
  • The Failure Scenario, Existing Diagnostic Monitoring and System Response fields and the Initial/Revised Frequency and Initial/Revised Monitoring ratings are for FMEA-MSR analysis.

Note: The Filter Code field is intended to allow users to follow the AIAG & VDA FMEA Handbook released in 2019.

Tip: If you need to define the reliability/maintainability characteristics for this record, use the FMRA tab. These characteristics will be applicable if you wish to perform criticality analysis, use the FMEA occurrence ratings to calculate a preliminary baseline estimate of the system reliability, share system configuration/reliability data between the software and BlockSim or perform RCM cost/availability calculations in RCM++.

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