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Visual Inspection

Discussion in 'Sampling, Standards and Inspection' started by essegn, Apr 23, 2018.

  1. essegn

    essegn Member

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    Dear Users,



    I am currently partially responsible for the inspection of produced goods and have an unusual problem to solve - it will be probably one Six Sigma Project. The inspection department (visual inspection) checks the produced parts and the all parts. Those which fail, are scanned with the problem description (into ERP) and are moved to a certain place in the department.

    All these parts are later being checked by one engineer, who makes the final decision, whether the parts need to be reworked or if a complete new part is needed.

    So far so good, but round about 70% of these parts are passed from the engineer as good ones.

    There are almost zero customer claims (2-3 in a year) so it means that the engineer and the inspection department do a really good job.


    It seems like the stuff in the inspection department needs to be additionally trained. But every part, which they exclude looks to be out of tolerance / norm (visual inspection).

    There exists a ‘’grey zone’’ and it looks like to me like following:

    · Everything within the tolerances / Norms

    · Out of tolerance – but still somehow acceptable (from engineer’s experience)

    · Out of tolerance


    I was wondering to teach the stuff in the inspection department, how to evaluate such a critical parts to be consider, but on the other hand to teach them, to send the parts out of tolerance out. I can understand their feelings, to do not risk any customer claim and do not have such a responsibility as the engineer. The invention to change the situation is obvious - to shorten the throughput time and costs for the engineer.


    I am aware, that In this kind of problems opinion of inspection people is very important, periodic meeting discussing action plans and results help a lot, give confidence to them. I can imagine, to work together with an engineer by evaluation of suspected parts to gain a sense to make a decision. One of the other option could be providing a board with Go-No Go samples, but I am still somehow confused and would like to know any proposal, how to manage this situation.

    Regards,
     
  2. Bev D

    Bev D Moderator Staff Member

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    don't use opinion, use facts.
    first confirm that the engineer is 'passing' out of tolerance parts. if they are, confirm that the accepted parts really do not cause a quality problem in the field. be cautios here as Customers don't always complain...perhaps the good, grey and failing parts can be tested to determine their effect on the Customer... if the parts are OK change the tolerance.
    then retrain the inspectors and perform a visual MSA
     
    RoxaneB and Andy Nichols like this.
  3. Golfman25

    Golfman25 Well-Known Member

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    What are the visual criteria? Is it something broad like "no marks" or more specific?
     
  4. johnnymo77

    johnnymo77 Active Member

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    I don't think Inspectors should be passing nonconforming material. I like the idea of the Engineer signing off in a material review. I think your QE or QM should be signing off also to protect the customer.

    Also, if there are no complaints you may be able to get the customer to change the acceptability requirements. But, I have had most customers say no, make it to the print.

    You also run the risk of your part being acceptable now when the mating parts at the customer are in spec to one side of the tolerance. Your part may not be acceptable if the mating parts are out of spec or shift to the other side of the tolerance band.
     
  5. essegn

    essegn Member

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    Many thanks for your inputs. The visual criteria are defined by one of MIL-Norms. There are certain tolerances for scratches and digs.
    It seems that i need to spend more time there to observe defects - especially the defects that are being refused by the inspectors and passed by engineer.
     

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