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Error proofing

Discussion in 'IATF 16949:2016 - Automotive Quality Systems' started by bkirch, Jun 4, 2019.

  1. bkirch

    bkirch Active Member

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    IATF 16949 defines error proofing as "product and manufacturing process design and development to prevent manufacture of nonconforming products." Suppose you have a device in place that doesn't prevent the manufacturing of nonconforming products, but it does prevent the nonconforming product from moving forward in the manufacturing process, would this also be error proofing?
     
  2. Andy Nichols

    Andy Nichols Moderator Staff Member

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    No, because you have caused non-conforming product to be made. What is described is control of nonconforming outputs.
     
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  3. Bev D

    Bev D Moderator Staff Member

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    There is a broad class of “poke yoke” that addresses “error proofing”.
    Level 1 stops the error. (I pick up the wrong screw)
    Level 2 stops the defect resulting form the error. (I install the wrong screw)
    Level 3 detects the defect before it proceeds/ships. (The wrong screw is shipped in the product)

    So it is easy to understand how people can become confused. But the standard is clear in it’s definition of “error proofing” as preventing the manufacture of the defect (level 2)

    *the level order may be reversed, its been a awhile since I cared about the level order, I concentrate on the actions themselves
     
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  4. Golfman25

    Golfman25 Well-Known Member

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    This is correct. And IATF only confuses things with their definition. Typical.
     
  5. Deepak Kumar Dutta

    Deepak Kumar Dutta New Member

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    Kindly share some documented procedures as per IATF 16949:2016.
     
  6. tony s

    tony s Well-Known Member

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    I don't think a documented procedure is needed to determine error-proofing methods. The error-proofing methods as indicated in the FMEA, and subsequently, in the Control Plan, can adequately satisfy clause 10.2.4.
     
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  7. Bob Sutton

    Bob Sutton New Member

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    I feel the need to jump into the world of error proofing. Like many people, I also struggle with being able to quickly determine if something is or is not a error proofing device (especially when trying to use the IATF definition). Having said that, I'm looking for feedback on a different aspect of 10.2.4 Error Proofing requirements, specifically "Error-proofing device failures shall have a reaction plan." We maintain a list of error proofing devices. This list contains information such as PFMEA line item #, method/frequency for testing EP device, location of device, challenge part used etc.. We have tried to determine the contingency plan for each device. Sometimes the contingency plan is to stop production until device is repaired/replaced (we produce and keep at least two days of customer product on hand at all times giving us time to repair/replace). Often we tend to document a contingency plan we think we will implement if and when the EP Device fails to function (such as a manual operation/inspection). We than feel that we must add the contingency plan (to include determining all potential failure modes and control methods) to PFMEA/CP. Right now we do not have these proposed contingency plans in our 100+ PFMEAs/CPs. This years annual review of each PFMEA/CP will include adding the contingency plans. This will require a lot of work that I'm not sure is the right thing to do for two reasons: 1) It is a fairly rare occurrence to have a EP Device fail to function and 2) what we deem as the contingency plan today may not be the actual contingency plan we want to implement when the time to do so arrives.

    Here is what I'm thinking. On our list of EP devices we have a column identified as "contingency plan". Why can't we simply say that the contingency plan will be documented via our alert system (temporary process memo) at the time we need to implement a contingency plan. Prior to releasing the TPM (temporary process memo) the PFMEA and CP will be updated in support of the contingency plan. We can revise our TPM document to have a question asking if the TPM is in support of a by-passing a EP device and if so, does PFMEA/CP speak to by-pass (contingency plan) method.

    Would be interested in people's opinion as to whether I'm living in a dream world (dreaming that what I'm thinking would meet the requirement).
     
  8. Andy Nichols

    Andy Nichols Moderator Staff Member

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    When you mention "contingency plans", is this your organization's terminology for "Reaction plan?" A reaction plan isn't - at least in my mind - even close to a contingency plan. How an ineffective "red rabbit" check is dealt with, would be a reaction plan - for example: Quarantine previous shift's products, inspect/sort for problems caused, check previous first-off samples etc., correct the faulty red rabbit, establish "clean point" which demonstrates error proofing is working again and so on.

    Swapping terminology - specially when IATF has specific references to these plans and are quite different, might cause you problems later on with auditors etc.

    All you need to do, however infrequent the issue is, is document your reaction plan (as mentioned above.
     
  9. Bob Sutton

    Bob Sutton New Member

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    I tell ya, there are days I make life complicated by not using the right words. I totally agree with you. We definitely have reaction plans for all error proofing device failures. It appears that pre-bob (prior to me working here) section “6.1.2.3 Contingency plans” was interpreted to mean that we had to have a known documented contingency plan for each error proofing device to include having said contingency plan already documented in the PFMEA/CP. I do not interpret 6.1.2.3 this way. Your thoughts?

     
  10. Andy Nichols

    Andy Nichols Moderator Staff Member

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    Yeah, you got it right. Contingency is all about supply chain resiliency. Power outages, labor disputes/strikes, magnesium foundries burning to the ground...that type of thing, and how to manage without shutting the customers' assembly plants down.
     
  11. Bob Sutton

    Bob Sutton New Member

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    Within the GM IATF Supplemental requirements section 8.6.1.1 GM has the following requirement "The organization shall keep a list of all error proofing devices and identify which can be bypassed and which cannot (also see clause 8.5.6.1.1). The bypass determination shall consider safety, severity and overall RPN rating." It has been explained to me that this is the specific requirement that is driving us to have to develop, document (in PFMEAs/CPs) the contingency (by-pass) plan for each and every error proofing device.
    I'm thinking that we would me this GM requirement by doing the following: On our list of EP devices we have a column identified as "contingency plan" (we will change it to "By-pass plan". Why can't we simply say that the by-pass plan will be documented via our alert system (temporary process memo) at the time we need to implement a contingency plan. Prior to releasing the TPM (temporary process memo) the PFMEA and CP will be updated in support of the by-pass plan. We can revise our TPM document to have a question asking if the TPM is in support of a by-passing a EP device and if so, does PFMEA/CP speak to by-pass method.
     
  12. tony s

    tony s Well-Known Member

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    There's no requirement for a "plan" in this statement: "The organization shall keep a list of all error proofing devices and identify which can be bypassed and which cannot (also see clause 8.5.6.1.1). The bypass determination shall consider safety, severity and overall RPN rating".

    Bypass is defined as "Proactive approach to address potential error proofing failures with a defined and approved process which addresses the risk as defined in the PFMEA, considering safety, severity and overall RPN rating. Bypass process is established before a device failure. Bypass differs from a deviation process as a deviation process is a reactive process".

    There could be instances that error proofing devices such as sensors will fail to detect errors (e.g. due to production parts orientation). Bypass controls could be mechanisms that correct the orientation of the parts before they pass through the sensors.
     
  13. Bob Sutton

    Bob Sutton New Member

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    Hello Tony, Where can I find the Bypass definition you quoted? Thanks
     
  14. tony s

    tony s Well-Known Member

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    See section 3 of this document.