James A


  • Does it matter to you if deliveries are earlier than planned?  If not, just use + days after due date, and then use standard notation of (mean delivery time minus 0) divided by 3 standard deviations – as for a unilateral tolerance to give you a CpK figure for smaller-is-better.
    Not thought through fully – just typed and posted – but it might be…[Read more]

  • I agree with Gabriel – especially the part about LSL=0 and USL=10 being confusing if you don’t really mean it.  If you get run over by a bus or visiting alien spacecraft then your successor needs to be able to see your logic easily in any of your calculations.
    If you have unilateral tolerancing, stick with (USL-Mean)/3sd or (Mean-LSL)/3sd…[Read more]

  • Reinaldo,
    If you post a message with “To iSixSigma Community” in the subject line, and the question in the body of the message, then someone with site responsibility might pick up your request and give you the details how to email the paper to them for posting to the site.
    I don’t know for sure, but it might work.  Just a suggestion.
    James A

  • Hans,
    There have been a couple of good threads on this in the past – I think if you were to use the ‘Search’ facility you will be able to track them down fairly easily – I think the titles were something like “Six Sigma Average”, or “Company Six Sigma Value”.
    From memory I think opinions were divided on whether a company average was really that…[Read more]

  • Ovidiu,
    No disagreements with you there – I can blame the Babel fish for this one, I think.  My misunderstanding.
    James A

  • Ovidiu,
    I know how you are thinking – I’ve been there.  What if your demand suddenly changes?  Where will your bottleneck be?  The key is in the understanding that there is always a (Pareto) of bottlenecks for every process – depending on demand you may not directly feel the effects as process pain, but they will be there.  Consequently if you…[Read more]

  • James A replied to the topic Inventory in the forum General 19 years, 10 months ago

    Sorry to butt in on this thread, but to support what Ron has said – we do the same thing.  In effect your stores area beomes like a bonded warehouse – you only pay for the parts as they are withdrawn from the consignment stock. 
    Ron is right, it’s a great idea, and it works really well – you just need to get your suppliers to agree to it – and t…[Read more]

  • James A replied to the topic Calibration Frequency in the forum General 19 years, 10 months ago

    Hello Mel,
    I don’t think there is a stated rule or standard for how often any gauge or measuring device is calibrated.  Generally, gauging of any sort is calibrated according to how much use it gets, and how much it wears between calibrations. 
    E.G.  if a gauge’s history shows it wears appreciably between calibrations, then it should be ca…[Read more]

  • OK Billybob, let me suggest the following:-
    1) Long term, you need to simplify the system – so that the data gets entered once into a data ‘pool’ and can be accessed by all interested parties direct from there – so reducing errors.  Your systems/IT people should be able to come up with a few good(?) ways of doing this – a relational/SQL…[Read more]

  • Norrin,
    I think Gabriel and Lee have both answered this during their daylight hours.  I think Gabriel is correct in that a copy of the AIAG manual would be very useful – it will help to give you confidence that you are heading in the right direction.
    Good luck.
    James A

  • Norrin,
    I had to look this one up – it’s been a while.
    1. For each set of results, calculate the proportion defective, for your data e.g. (21/462), (11/309) etc.
    2. Add all the above numbers together, and then divide by the total number of parts inspected – this will give you p-bar.
    The UCLp = (p-bar + 3*sqrt of p-bar*(1-p-bar))  / sqrt…[Read more]

  • Abhinav,
    What is in the section headed “Six Sigma Basics” ?
    (left and below in the blue column – it might help)
    James A

  • YourDictionary(dot)com supplies the following definitions:
    Main Entry: “i-n&-‘vA-sh&nFunction: nounDate: 15th century1 : the introduction of something new2 : a new idea, method, or device : NOVELTY- /-shn&l, -sh&-n[^&]l/ adjective

    And for variation (not all listed):-
    Main Entry:…[Read more]

  • Annonymous,
    Do please use the example if it helps – I thought about this overnight (sad, isn’t it) because when I was typing the story I was unsure if the score was seven or eight – so seeing your response this morning confirms in my own mind that I was probably wrong in saying 8, and that it should have been 7.
    Either way, it’s a…[Read more]

  • James A replied to the topic DOE Sample Size in the forum General 19 years, 10 months ago

    I remember my DOE trainer saying that averaging data loses you good information, and the more you average, the more you lose.  I think it was good advice.
    I’d stick to your guns.
    Just my tuppence worth.
    James A.

  • Gabriel (and Mike),
    Maybe I’m being pedantic here, and I don’t wish to start WW III, but to take Gabriel’s points in order:-
    1) If incoming parts are no good, then that is the fault of the previous FMEA team – they didn’t do the job properly (used a ‘template’ FMEA, or carry-over FMEA, one man wrote it, or they just didn’t think).
    After the…[Read more]

  • Let me guess, the hesitant nay-saying stakeholders are also the ones who feel they will be blamed, right?
    I haven’t worked on an identical project, but the problem you have here is the really tough one of changing attitudes – this is the one you don’t get a bunch of tools for, and for which dear old Minitab just won’t help.
    May I suggest that…[Read more]

  • Amit,
    Yes you restrict yourself to the process only.  At each stage of the process you have to assume that (1) Incoming product from either the previous process, or (2) the raw material is AOK.
    So to answer your second papragraph, characteristics related to the input for that process can not be taken as a cause (as it should have been…[Read more]

  • Good question Mary,
    A few thoughts if I may . . . .
    For the first part, I have worked in companies where there is a centralised ‘Corporate’ function.  The advantages of this are that the ‘consultants’ called in can operate outside the petty vested interest bickering often found internally – and can just get on with the job.  They are not c…[Read more]

  • James A replied to the topic Chii Square test in the forum General 19 years, 11 months ago

    I have just given myself a quick refresher on Chi sqrd tests – I was wrong in my views about expected not being greater than observed. But I’ve (re-) learned something, so that must be good.
    Having cleared my conscience, I can now go home.
    James A

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