iSixSigma

Karim Mohsen

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Viewing 23 posts - 1 through 23 (of 23 total)
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  • #237173

    Karim Mohsen
    Participant

    @cseider

    but i think that 6 samples are too few to do capability analysis ,or do you mean to combine the all 6 samples of the 30 batch in one capability analysis and one control chart ? if you mean this so , it will be more reasonable than that the customer want , the only disadvantage of this is that it will take very long time to achieve and in this case it is better to use X bar and R chat , right?

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    #237098

    Karim Mohsen
    Participant

    @rbutler

    30 sample from each batch for total 180 samples , he wants to run the capability and control chart for each batch

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    #237095

    Karim Mohsen
    Participant

    @cseider
    it is customer request , to do the capability and the control chart of 30 samples from different 6 batches each

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    #203119

    Karim Mohsen
    Participant

    could you please explain to me when i can use the shifting as a solution , i google it but i can’t understand
    i know that i must find the causes of the variation either they are special or common causes but i also know that i may use the solution of shifting the process mean as one of the solutions

    could you please clarify this

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    #203117

    Karim Mohsen
    Participant

    @rbutler

    but suppose that the results moving toward the upper spec. limit , so if i can move the specs little bit and examine the process again and gives me better CPk, isn’t this may consider a fast solution ?

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    #203104

    Karim Mohsen
    Participant

    @rbutler

    more variables like what that may impact variation than operators and machines ?

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    #203026

    Karim Mohsen
    Participant

    @rbutler Thank you for you great effort, what a genius answer !!!!!!!!!!!

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    #202266

    Karim Mohsen
    Participant

    Hi @rbutler ,

    1-The batch is done in one blender ( a batch consists of the output of a single reactor vessel)
    2- when i said that the process is normal before the modification I mean that i did the analysis of 9 batch ( 30 sample each) to examine the performance of my process before i start the six sigma project
    3- all the batches i examine was normally distributed but the process was not centered to the target most of the outcomes results were at the right side (in the upper range side (from 15.1 to 15.9) noted that the my specs is (13.9 to 15.9) my target is 14.9

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    #202263

    Karim Mohsen
    Participant

    Dear @rbutler

    First, I am sorry if i am bothering you with my questions but as i mentioned before I am new in six sigma and this is my first six sigma project and i need to understand more

    second, let me show you what i am working on
    1- i am working on flavor powder and i am measuring the chloride content of it
    2- my goal is to achieve cpk 1.33 according to the chloride content results
    3- the 9326893 is number of batch its quantity is 900 kg packed in 36 carton box (25kg each)
    4- i withdraw 30 sample from 30 carton and measure the chloride content of each
    5- i have worked or one year now to adjust the cpk and go thorough the six sigma project to find the cause and effect of what is wrong and i did some modification in the process to adjust the cpk
    6- before the modifications the process was normal but the cpk was bad
    7- by trying modification one by one i found that the cpk is becoming better but the process isn’t normal which made me confuse
    8- my measurement Gage is well calibrated before each trail
    9- when i studied the six sigma green belt they didn’t mention to me how to do capability for non normal data and how to interpret it

    Finally, what do you mean by the expression (cherry picked)

    Thank you and I appreciate your effort

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    #202261

    Karim Mohsen
    Participant

    what is the optimal value of the lambda to be considered ?

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    #202258

    Karim Mohsen
    Participant

    @cseider

    why 13.9**5 ……why 5 especially is it constant factor or depends on what ?

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    #202257

    Karim Mohsen
    Participant

    @butler

    will the process be stable by time or i need to make shifting to left or a modification to the process itself?

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    #202251

    Karim Mohsen
    Participant

    I did what you sent me but still the same

    you said that the transformation happened to the spces and data , but i can’t found any relation between the 2 number ( i mean after and before transformation)

    noted that it is the first time i deal with the transformation , so i can’t understand anything

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    #202249

    Karim Mohsen
    Participant

    The data in the my previous reply
    but could you explain the transformation that happened ?

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    #202246

    Karim Mohsen
    Participant

    here is the data
    My specs = 13.9 – 15.9
    Target 14.9

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    #202244

    Karim Mohsen
    Participant

    @cseider

    yes the data failed normality test P = 0.005

    I want to know how to read the capability after transformation what it telling me exactly ?

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    #202242

    Karim Mohsen
    Participant

    Sorry @rbuttler & @cseider,
    i had done a mistake the two pics are the same let me show you the correct ones

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    #202238

    Karim Mohsen
    Participant

    @cseider

    the first pic after transformation and the second pic before transformation

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    #202234

    Karim Mohsen
    Participant

    the second one

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    #202233

    Karim Mohsen
    Participant

    what i can understand from the two pics

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    #202207

    Karim Mohsen
    Participant

    @rbutler
    Hi Robert,
    could you please tell me the different between 1 sample Z & 1 sample t ?

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    #202197

    Karim Mohsen
    Participant

    here it is the plot of the data

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    #202193

    Karim Mohsen
    Participant

    Hello Robert,

    Thanks for your reply and let me share with you some of my data information

    1- my sample size is 30 samples
    2- all my data i have got is within the specification limit 14.9 +/- 1
    3- I put my data in the control chart I-MR chart to check if there is any special causes or not and the result is that there is no any special causes
    4- The P-value I got is 0.04 (left skewed)
    5- The CpK i got is 1.01
    6- As my data is not normal i test 1-sample wilcoxon test and i got the following :
    Confidence
    Estimated Achieved Interval
    N Median Confidence Lower Upper
    s.c 30 14.70 94.9 14.60 14.80

    Test of median = 14.90 versus median ≠ 14.90

    N for Wilcoxon Estimated
    N Test Statistic P Median
    s.c 30 24 22.5 0.000 14.70

    Could you help me to judge on this

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Viewing 23 posts - 1 through 23 (of 23 total)