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Potential Failure Mode

Discussion in 'FMEA - Failure Modes and Effects Analysis' started by ar85dan, Jul 12, 2019.

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  1. ar85dan

    ar85dan New Member

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    Hello all,

    I have a question, something i am not sure i understood correctly about the PFMEA.
    I am talking about a sunshade, which afterwards the customer places it in the back door of a car.
    I have process step 1 (final station assembly) and process step 2 (checking station). In process step 1 I assemble the product and check some characteristics (Eg. Force in the fabric) and in process step 2 i only check the characteristics that i cannot check in process step 1, no other assembly.
    For example, only in process step 2 I can check if the fabric from the product is not wavy on the sides, because i have a jig that simulates the door and can see how the product looks. But this waviness appears because of nok process in process step 1.
    My question is, what do I write for process step 2 as potential failure mode?
    For example do I write this "waviness" at process step 2, because i detect it here, or at process step 1, because i create it here?
    Or do I write only failures that i can make at process step 2? (in my case, as there is no assembly, i would write none!??)
    Hope i was clear enough.

    Thanks for your help
     
  2. Miner

    Miner Moderator Staff Member

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    I would list waviness as a failure mode in the process step that created it. Your detection would be the next process step where you inspect for it. At process step 2 your failure modes would be accepting a wavy part, rejecting a good part or bypassing the inspection..
     
  3. Andy Nichols

    Andy Nichols Moderator Staff Member

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    Are you asking about a Design FMEA or a Process FMEA. It seems to me that you are checking the design, not the assembly process. I'd have to see more details of your FMEA
     
  4. tony s

    tony s Well-Known Member

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    I would prefer to enter "waviness" in the Potential Effect/s of Failure of your PFMEA for process 1. As per the AIAG manual "The effects of the failure should be described in terms of what the customer might notice or experience... The customer in this context could be the next operation..."

    You have already given us a hint of the Potential Failure Mode when you mentioned "this waviness appears because of nok process in process step 1". What is that "nok process"? This could be the failure that you need to address (e.g. inadequate force applied in the fabric). Again in the AIAG manual, potential failure mode is defined as "the manner in which the process could potentially fail to meet the process requirement (including the design intent)". No waviness here could be the design intent.

    Process 2, as you mentioned, is the checking station. Failures that can happen here should be associated with the checking process like jig not set properly.
     
    Last edited: Jul 14, 2019
    John C. Abnet likes this.
  5. ar85dan

    ar85dan New Member

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    I am checking the "design" because i glue a pipe on a fabric. if i do not glue this pipe correctly (eg. one side of the pipe is too up or too low compared to the correct position against the fabric) then i will get a wavy fabric (and other issues).
     
  6. ar85dan

    ar85dan New Member

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    I thought like this, for process step 2 (where i only check the product)
    Failure mode: Waves Effect of failure: bad appearance at customer (or something similar) cause of failure: incorrect gluing of fabric against pipe prevention: stoppers on table to assure same gluing position, detection: 100% visual check on checking station (process step 2)

    OR write it at process step 1 (where i do the assembly)

    Failure mode: incorrect gluing of pipe against fabric effect: waves cause: not properly controlled process of gluing prevention: stoppers to assure same position always, detection: 100% visual check on checking station
     
  7. tony s

    tony s Well-Known Member

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    This is more proper.
     
  8. ar85dan

    ar85dan New Member

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    Then my question would be, what do i write at process step 2, where i do not assemble?
     
  9. tony s

    tony s Well-Known Member

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    I've given you some points already in this post.
    Take it from here.
     
  10. Andy Nichols

    Andy Nichols Moderator Staff Member

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    ar85dan - map your process and post it here. Let's see what you have - that will help!
     

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