PFMEA : Operator Control Effectiveness evaluation.

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    Recent we were reviewing the Process FMEA related to a failure mode which were leading to frequent customer complaints. During the review, we found that many key controls are humans (operators). The RPN number of such a failure cause is quite high (150-175). The ratings are performed as per AIAG FMEA 3rd edition.
    The question is, when you have process control as “operator control”, which is not a preferred control because it is not effective “mistake proofing”, what approach would help us in reducing the risk associated with the occurance of cause leading to customer complinas?
    I hope any of you would have encountered such situations in Six Sigma projects & PFMEA reviews.
    Ideas welcome.


    adam shen

    Actually ,human factor is complicated.
    Based on my experience, training + OS(operation standard)+ process design+ IE + QA audit + Auto-test is useful to reduce workmanship loss.



    Do you refer to operator control visual or measurement ? As general answer there are some very basicaly ‘mistake proof techniques’ that can be used to avoid, human errors, but to go in more detailed discussion, please give me other details.
    Rgs, Peppe. 



    Hi PGK,
    Human control cannot be referred to as ‘ mistake-proffing’. Mistake proofing is something, which will help you to prevent the defect to happen.
    In this case, depending on the severity of the failure mode, the process may have to be re-desgined, so that the process is ‘mistake -prooffed’. Eg. : We use swip card, which makes the system mistake prooffed, as no stranger can enter your office without using swip cards.
    In processes, wherein technology cannot be used, you should have a good mechanism by which atleast defect can be detected before it’s impact is seen at the customer end. For that you may have to do brainstorming, check with industry best practices, promote innovation etc.



    Hi PGK,
    A problem, in your case customer claims, brought about by human factor is something that is not very easy to handle and indeed, promotion of mistake- proofing or poka-yoke devices is a very good way to tackle this. Of course, not all operation systems could be made automatic, installing devices, sensors, etc. as these are costly but there is Visual Control and 5S. Going down to the human aspect , one must check too the motivation factor of the person involve. Sometimes, when all the “why’s” are all used up, it boils down to the aspect of behavioral training. Even though how good a procedure is, it is still at up to the operator if he would do it or not.



    Dear Sir,
    When the processes are operator dominant, pl. introduce Poka Yokes to the maximum possible extent.They should be preventive as well as detecting type.
    Pl refer to book on poka Yoke by Shingeo Shingo.



    Whenever the operator is involved with missed or incorrectly applied steps, many methods could help to improve this.  Certainly better auto controls, costly, but effective.  Operator Work Instructions, followed and Auditted and maybe even Check Sheets to see after the fact that the operator indeed followed the Work Instructions.  These can be effective in both identifying and resolving  problem operators as well as rewarding those who follow through. Without knowing more, I hesitate to suggest other, but committed operators is the ONLY way to go.



    Dear Mr. PGK,
    In such a situation, you have to look at your SOP and training for the process. In the SOP, give thrust on “why”, (why the step is important ?) along with how. Another important thing is to introduce audit system for SOP.
    You may also stratify the complaints operator wise to know if it is related to skill of some operator. In such case, introduce introduce self learning system ( more skilled one educating the less educating one).
    Exposing the operating team to the problems faced by customers is another improvement ideas.
    Try and identify, which aspect ( activity, process/machine  part) of the operator is responsible for the cause to happen. Corrective action may flow from there also.



    If this is the only control you have, you must resort to training. Train, Train, Train, until they know this process cold! You can also look at the actual process and see if there are any steps that can be eliminated, any time you make a process less complex, the easier it will be for humans to control it.



    Keys to helping operators not make mistakes are:
    Standardized work with very simple, visual instructions.
    Use TWI training methods (Training Within Industry – the origins of lean and great training methodology)
    Poke-a-yoke fixturing design
    Designing the process so that operator tasks are within their skill set. You may have to add some automation.
    A. Levine

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