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Inspection Process Optimization

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  • #48856

    Bill C
    Participant

    Can anyone share insight on how to make an inspection process more effective? I realize you can’t inspect quality into a part, but we have many opportunities for defects at this point, and are focusing on containment. We have an inspection checklist of perhaps 40 items, and we tend to miss defects to some extent.
    I am not looking for gage study recommendations. Any innovative ideas towards making a manual inspection process closer to 100% effective?

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    #165767

    ycm
    Member

    Hi bill C,
    In your case, it would seem that your process depend on operators for the checking of parts. So a way to make your process more capable is to have more training for the inspectors.
    Other than more training for the operators, u can also standardize the way that a part is being inspected.
     
    tcm

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    #165768

    tcm
    Member

    omg….. a typo …………
    >.<
    tcm

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    #165769

    Dr. Scott
    Participant

    Bill C,
    Why on earth would you exclude a gage or MSA study? To me that is where you need to start. The outcomes of that will tell where to go next.
    Regards,
    Dr. Scott

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    #165770

    JD
    Participant

    Adding another layer of inspectors would minimize the chances of escaping defects. If the probability of escaping defects is 0.1 in first place, then it will reduce to 0.01 afterwards.

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    #165771

    Six Sigma Shooter
    Member

    Hmmm . . . . is it just me, or does this sound like the Red Beads Experiment in real life?  If one more layer of inspectors is good, why not add two or three more layers, just ot make sure we catch them all?  In fact, adding layers of inspection only worsens the problem, robs the process worker of ownership for the quality of the products they make, and increases the costs of goods sold for no real benefit.  I agree with Doc – do the MSA and find out where the problem is.  Then solve it – or better yet, remove the reasons for the defects.  Hey, now there’s a unique thought – improve the process!

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    #165776

    Bill C
    Participant

    Regarding the question about the gage study….we know that we miss defects. I am looking for innovative ways for quick containment without piling up layers of inspections. If Dr Scott could give me some hypotheticals…that would be great. If your gage study result is X then do Y.
    Ideas that I am seeking would consist of better visual aids, work stations with less distractions, being more methodical with the inspection, etc. In other words, ideas from all the experts that have had proven results. 
    To reiterate, we are focusing on containment and realize that we can’t inspect quality in. (Hence we are launching a project to “fix the process”).

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    #165777

    Aurum
    Participant

    Bill,
    Do you check after each step of the process or at the end of the process?
    If you check at each step of the process, can you use automation?
    If you check at the end of the process, can you re-design your process as a single-flow line?
    If you can check after each step, can you collect or create some material or components with defects for a non-conforming materials library.
    Once you have your own standards you can test the accuracy and repeatability of each operator as the gentleman suggested.
    Once you detect defects, you should stop your production line and investigate the true cause until the production manager comes down from his office, kicks you butt, and tells you you’re only an engineer. You can then find a better paid job selling Toyota cars.
    Aurum

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    #166070

    Michael Schlueter
    Participant

    Hello Bill,
    Can you please give me an example of what you’re doing? Which defects did occur already? Do they come up again? Which defect was newly discovered? And so on. I’d like to have an idea about your concrete situation.
    What would help you, ideally? Would an exhaustive list of all defects help you? More precisely, not all defects possible, but all effects likely to be produced through your process?
    Assume, you solved your problem of “not overlooking defects”. What would be your the next step?
    Thanks and kind regards, Michael Schlueter

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    #166083

    Perryman
    Participant

    Bill,
    If you know you are missing some defects in the inspection process, do you know which ones are slipping through?  Are there any trends? This may be able to help you focus your improvement efforts.  With this information, you may also look back upstream rather than at the inspection stage, to see if you can mistake proof those errors or at least catch them earlier on.
    Hope this helps,
    Patch

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    #166088

    AlexanderSO
    Participant

    Bill, I think that the problem should be addressed with an statistical approach, and insteed of putting extra effort on inspection you should find and minimize the sources of variation at the source of the defects, in the long term it makes no difference to improve the inspection method allowing you to catch all the defective units, at the end the cost of bad quality still be high, you will no have claims from customers but you´ll have a lot of rejected units waiting for overprocess or to be scraped, and this will not give real benefit to the bussiness.

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    #166091

    porch45
    Participant

    I would pareto which failures you are seeing.  Which characteristics are causing you the most problem.  Once identified, you can start your improvement activities.  Why is it a problem?  Is it operator dependant?  Wrong tooling or gauging?  This is where MSAs can help you out.  Lots of times the Blue print dimensions are not being interpreted correctly.  In our facility we have several very old drawings, as well as new drawings, resulting in different GD&T standards over the years.  Are all the operators in agreement of what the different GD&T standards are and how it affects their measurements and interpretations?
    You could also look at which of the characteristics are critical or key and really focus on them.  A lot of dimensions are lots of times not as critical as others.  
     

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    #166092

    Six Sigma Shooter
    Member

    Aha!  And here we get to the crux of the matter.  You will always have inspection escapes that get to the customer, no matter how good you think your inspection is or how well it is optimized.  This is the problem with a focus on defects reduction rather than a focus on minimizing variation,  Zero defects programs and inspection are not enough and they do not protect the customer from our mistakes.  Optimizing inspection is a dark and deep hole.
    Shooter

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    #166100

    KT
    Participant

    In theory perhaps, in reality when you inspect twice AOQL goes DOWN because human nature ASSUMES the other guy will catch it.  (Actually I have overcome this by CAREFULLY designing incentive payments which reward re-inspection at the cost of inspection!)  More effective is employing two inspectors and dividing the area of accountability in half.

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    #166128

    PB
    Participant

    Bill,I agree with Shooter. However, as the question you have asked is regarding optimization of the inspection (which I take it are attribute type inspections), I would do the following:- Identify areas of inspection on a print and provide training to operators so that they are aware of what to look for in that area of the product. Even having pictures of the defects at the work benches would be good visual tool.- Create a rotation of operators for inspection so that they are focused on specific areas for inspection on the product.- Have operators inspect less parts but more of. So, instead of inspecting 30, they can inspect 10 but three times randomly.- Test your operators’ on their knowledge of defects which you know have gone through and need to be caught. Provide training if necesary.- Work on the process.Hope this helps.PB

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    #166129

    Bill C
    Participant

    I can’t give too much detail, but:
    It is a highly complex unit the size of an extra large toaster and is manually assembled. We use staking compound and sometimes it gets into areas where it shouldn’t. In some cases we are to use locktite on hardware and torque to certain values. The customer has found loose hardware that has escaped. The list goes on.  Our inspection process is around 90% effective at this point.
    Right now I am focusing on visual aids, and methodical verifications. I am considering the FMEA approach on the manufacturing side along with some input/output diagrams to convey the critical information.
     

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    #166130

    Bill C
    Participant

    PB / Shooter,
    Good advice. Thanks!
    This kind of reminds me of the f-test from one of my training classes. Not ANOVA of course, but the test were you are given a short article and are asked to count how many F’s appear. It’s funny how many different counts there are among the class members!

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    #166131

    Adam L Bowden
    Participant

    Make inspection more effective …There are lots of answers as how to improve the inspection process
    but … you should focus also on …
    – eliminating inspection as it’s non-value addedAlternative proactive approaches include product re-design,
    process automation etc etcSix sigma projects are successful if you do not have to keep baby
    sitting them – by “tactically” improving the inspection process you
    are doing just that.My alternative 2c worth.Adam

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    #166132

    Brandon
    Participant

    Bill C. – the answer is 34!!!
    Do I win anything?

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    #166141

    Michael Schlueter
    Participant

    Thank you, Bill.
     
    You may want to consider some of the following ideas.
     
    Is this assembly problem related to care and attention of the operators? Then a photo gallery of defects may be useful. May be even a side-by-side comparison between a good (excellent) and a bad (absolutely worse) product or assembly step. This helps people to understand, to learn and to talk about it.
     
    Did you consider talking to the operators? Many times they have enough observations, summaries of the situation or suggestions for improvement.
     
    Did you consider poka-yoke, i.e. fool-proof assembly? This way you’d allow only one way to do it either by design or tools used at assembly. Operators report they now can think about quality rather than doing the assembly right (it can’t go wrong).
     
    Can operators down the line recognize assembly faults done earlier? If so I still like the Toyota idea, where they encouraged doing a total belt-stop when recognizing a failure. It hardly performs in the beginning, but helps to spot trouble and sources of trouble in real-time. May be you can try this on one assembly line? If so, be sure to provide support for the nasty remarks to come – and to deal with people being envy on achievements.
     
    I like FMEA, but it’s shortcoming is related to our own imagination (what we think can or can’t happen). Even worse, I’ve seen too many FMEA’s mixing freely cause and effect and elaborating minor issues. There’s a better analysis tool available today, which helps you to focus and to reveal all known, all hidden and all available failure modes (seen or unseen) in your assembly process. Engineers think the process does something, while parts simply obey the laws of physics and the specific conditions met.
     
    If you want to know more about this FMEA++ method or would like to have a contact in the US please let me know (by posting your email address in a reply to this post).
     
    To me it sounds like the product design itself might benefit from an update. The way it’s designed and assembled today seems to leave room for trouble: it seems to be too sensitive to, e.g., operators concentration, may be variability of parts and compounds etc., perhaps even to customers usage conditions. This would call for a DoE, and, if you want to achieve extraordinary results, even a Taguchi DoE.
     
    Hope this helps.
     
    If you’d like more, please let me know.
     
    Kind regards, Michael Schlueter

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    #166144

    Naveen Sher
    Participant

    Dear Michael,
    As working in a plastic industry i have my opinino which is edited below.
    I personnaly feel that Analysing the part at design phase itself is to be looked for.Cross functional team comprising people from production, design & quality should be felt at design phase.Things which went wrong & things those went right to be considered also
    Mr. Naveen sher
    QA-Engineer
     
     

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    #166201

    Fordguy
    Participant

    AlexanderSO,
    How do you think Toyota improve their processes after their autonomous inspection find defects and they stop the line?
    What you seem to be advocating is the use of American TQM model, which eliminates checking and attempts to assure quality solely through the statistical approach. This implies the customers have to endure defective parts until you identify the sources of variation and eliminate them!
    This in essence is what is wrong with the American Quality approach and why companies like Ford are now trying to implement the Toyota Production System.
    Regards,
    Ford-guy

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    #166352

    AlexanderSO
    Participant

    Hi, I believe you are taking my comment a little bit to far, I´m not saying that the inspection procedure is unnecesary, it is requiered because is the stage when a lot of the defects are being detected, the way this inspection is performed depends of a lot of things related with the process, check list or pokajoke like in Toyota or many other ways used in industry.  What I´m trying to say is that a quality problem should not be adressed adding muscle to the inspection line, this effort wiil be more usefull aplying it on the source of variations or root causes, what Toyota did was creating a strong problem solving way of work and when the line was stopped they get around and look for the root cause and address it, this approach is not agains the use of smart statistics to monitor and address actions over a process, the feeling about the statistical approach is than in most industrial enviroments the solutions take too long to be implemented and much of this time have been asigned to the requiered time to perform statistical analysis (sometimes unneeded ).  But if you take a look at the industrial history of Japan since the end of the second world war, most of the success in bussiness dynamics and product quiality achieved by Japan industries is due to the intervention of Dr. Edwards Deming and his satistical approach to problem solving, and until today the Deming medal award is one of the most prestigious awards that a Japanese industry can obtain.

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    #166368

    Fordguy
    Participant

    With respect you do not seem to understand the Deming cycle and the principle of single-flow. You should not inspect at the end of the line or at a “problem stage” using extra muscle! Each step should check the work of the previous step, by whatever means.
     
     
     
     
     

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    #166383

    Mikel
    Member

    Fordguy,With all due respect, you seem to understand the theory, but why
    would we look to someone from Ford for guidance?Your Six Sigma program is a joke and you are at least 25 years into
    the best guidance a company could have – you had Deming in the
    80’s. The ideas of TPS and lean were clearly understood in the 80’s.
    Your middle management ranks are still bloated. What did I miss to make me want to look to Ford?PS – I own three Fords and a Harley, so I still want to believe that
    domestic companies and domestic production can be competitive.

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    #166393

    Fordguy
    Participant

    Good point Stan …
    If you still buy domestic products out of loyalty to your community, you ought to understand irony.

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    #166400

    Six Sigma Shooter
    Member

    Stan,
    I was at Ford during the Deming days.  Many of us took it seriously – even in the middle management ranks.  After The Duece stepped down and Phil Caldwell took over, though he was kind of luke warm to it all, he allowed Deming to have his say.  Don Petersen was much more serious about it all.  When he took over, we actually had some hope for the future.  He seemed to “get it” – at least more than most, anyway.  We saw the launch of some pretty good vehicles (T’Bird / Cougar, Escort) and the revival of some that hadn’t done so well.  And then came “my-hair’s-on-fire,” ‘Red’ Poling – another hard core, knock-down, dragout old school auto guy.  More to the liking of the Ford family, for sure.  It was over, and the downhill spiral began and hasn’t stopped.  In my opinion, it will continue until the Ford family gives up its control of the company.  As Dr. D. often admonished, don’t tamper and meddle with the people or the business.  Something the Ford family has never understood nor practiced.
    Shooter

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    #169513

    Hanmanth Patil
    Participant

    R/sir
    This is hanmanth Patil from India . i wish u would like to inform that
    i need some information in like
    SPC, TQM, FMEA,PPAP,CP,CPK, DFMEA,KAIZAN MATHOD,5S& HOUSE KEEPING , 7QC TOOLS , APQP,
    where is using the thease mathod & I need Quality Control Process & systems
     
    Thanking you
    Regards
    hanmanth patil

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