Dismiss Notice
You must be a registered member in order to post messages and view/download attached files in this forum.
Click here to register.

what exactly does "Class" mean in FMEA?

Discussion in 'FMEA - Failure Modes and Effects Analysis' started by John Michael Kane, Mar 6, 2019.

  1. John Michael Kane

    John Michael Kane Member

    Joined:
    Feb 26, 2019
    Messages:
    12
    Likes Received:
    1
    Trophy Points:
    2
    what exactly does "Class" mean in FMEA?
     
  2. Andy Nichols

    Andy Nichols Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    2,701
    Likes Received:
    1,370
    Trophy Points:
    112
    Location:
    In the "Rust Belt"
    Page 91 of the current AIAG manual defines "classification" as (paraphrased) highlight high priority failure modes or identifying important characteristics...
     
  3. tony s

    tony s Well-Known Member

    Joined:
    Sep 10, 2015
    Messages:
    885
    Likes Received:
    662
    Trophy Points:
    92
    Location:
    Laguna Philippines
    Just to add. The Classification column can also be used to classify any special product or process characteristics (e.g. safety, special, critical, key, major, significant). The Special Characteristic Classification column of the Control Plan should be taken into account when accomplishing the Classification column of the FMEA. Customer symbols (e.g. Chrysler's Shield, Ford's Inverted Delta, GM's Diamond) to identify special characteristics can be used as entries in the Classification column.

    Organizations can also develop their own classification. See the Classification Matrix below:

    upload_2019-3-16_17-31-7.png

    Those who use FMEAs need to learn that the classification value is more important than the RPN. Study the table below:

    upload_2019-3-16_17-34-13.png

    In this example, the RPN of 96 has less priority. However, the Classification Matrix (above) indicates that Failure Mode 1 falls within the Significant Zone, indicating a problem that will lead to significant vehicle/operation problem and cost the company money. Failure Mode 2 in this example shows an RPN of 160 that would raise flags for an auditor but doesn't fall into either the Critical Zone or Significant Zone.

    If the organization prioritize Failure Mode 2 due to its higher RPN, then actions would be developed to either prevent a cause that rarely results in a defect or inspect for a defect that rarely happens. All this will be done while the process is rejecting at 1/500 of its products (based on criteria for evaluating Occurrence) without any signs that action is needed.
     
    Atul Khandekar and Miner like this.

Share This Page