# Cusum chart?

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• #29260

Aguilar
Member

What is a cusum chart and what its used for?
What is statistical inference?

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#74444

QE
Participant

Victor,
A cusum chart is a type of control chart (cumulative sum control chart).  It is used to detect small changes between 0.5-2.5 sigma.  For larger shifts, Shewart-type charts are just as good and easier to use.  Cusum charts plot the cumulative sum of the deviations between each data point (a sample average) and a reference value, T.  Unlike other control charts, one studying a cusum chart will be concerned with the slope of the plotted line, not just the distance between plotted points and the centerline.  Critical limits for a cusum chart are not fixed or parallel.  And a mask in the shape of a V is usually laid over the chart with the origin over the last plotted point.  Previous points covered by the mask indicate the process has shifted.
So, who uses these types of charts?  Typically chemical industries.
Hope this helps!  BTW – a good reference book would be “Statistical Qaulity Design and Control – Contemporary Concepts and Methods”  I received it as part of my BB training, and it is an excellent resource.  Juran’s Quality Handbook is also handy.

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#74463

aa
Participant

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#74522

Aguilar
Member

Thanks for the answer, yes indeed iam still interested in the information about a “cusum chart” my e-mail is [email protected]
Thanks again!

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#74530

aa
Participant

Victor, I have made note for you email, will reply with the attachment. Also note, that isixsigma.com, plans to post the articles too.
watch the space.

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#74535

RR Kunes
Member

I’ve never seen one utilized in manufacturing in over twenty years. I would be interested to know if anyone out there currently uses these charts and in what applications.

0
#74536

iSixSigma Community
Participant

AA,
Just follow the directions found to the right of this post (highlighted “Post/Attach Document”) to post your document, and we’ll take care of the rest!

Best regards,
iSixSigma Community

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#74541

aa
Participant

Yes, RR Kunes – we do use them on daily basis for tread analysis on the production plant. An example: typically on our colour performance.
If you need to know let have your email.
regards
AA

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#74542

aa
Participant

Dear isixsigma.com,
Yes, I have done that, and also reply to your email. Check out our mailbox.
regards
AA

0
#74558

iSixSigma Community
Participant

AA,