If I had about 30 samples obtained from one batch produced in certain time and under same condition, which is better to use I-MR chart of X bar & R chart?
And which chart should i use if i had 30 results from 30 different batches produced in several days ?
what is meant by Cpk is for short term, Ppk is for long term.? And
Is Cpk tells you what the process is capable of doing in future,while Ppk tells you how the process has performed in the past?
please help to understand this
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
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 ?
is one of the improvement methods in six sigma is to make shifting to the mean of the process as a first step before starting six sigma project (DMAIC)?
and if it is possible how to make this shifting?
what is the difference between if the special cause appears in sample range and sample mean in control charts?
I know that it they appears in sample mean that is mean that there is problem in equipment or the operator
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…[Read more]
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…[Read more]
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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