topic Re: Cpk Analysis for many parameters in Discussions

Cpk Analysis for many parameters

OneNorthJMP — Thu, 21 Mar 2019 03:00:51 GMT

I understand we can get single or multiple parameters Cpk analysis by using the Process Capability. But that feature is useful to dive in to few parameters. But i need to run hundreds of parameters for Cpk and sort them ascendingly. Then i only check those parameters with low Cpk and look into more details like process capacility. Any idea how to achieve that?

Re: Cpk Analysis for many parameters

txnelson — Thu, 21 Mar 2019 05:52:32 GMT

Here is one way to get you started. It will work with any number of columns. It does make the assumption that the Spec Limits are embedded into the data columns, as Spec Limit column properties

names default to here(1);
// Open a sample data table that has the Column Property of "Spec Limits" set
dt=Open("$SAMPLE_DATA/Semiconductor Capability.jmp");

// Create a List that has all of the columns that need to be processed
colNamesList = dt << Get Column Names( String, continuous );

// Start to Build the command string to run all of the outputs
theExpr = "dist = dt << Distribution( invisible,";

// Loop across all of the required columns to generate the Cpks
For( i = 1, i<=Nitems(colNamesList), i++,
theExpr = theExpr || "Continuous Distribution( Column( " || colNamesList[i] || ")),";
);
// Finish up the command string 
theExpr = TheExpr || ");";
eval(Parse(theExpr));

// Create the data table with all of the capability stats
dtCap = report(Dist)["Long Term Sigma"][TableBox(1)]<<Make combined data table;

// Cleanup the used space
report(dist) << close window;

Re: Cpk Analysis for many parameters

ian_jmp — Thu, 21 Mar 2019 09:50:33 GMT

And you should also take a close look at the Process Screening platform. It was built for this kind of situation. Also see this very recent presentation by @Laura_Lancaster.

Re: Cpk Analysis for many parameters

txnelson — Thu, 21 Mar 2019 10:10:31 GMT

Ian's is a better solution

Re: Cpk Analysis for many parameters

OneNorthJMP — Fri, 22 Mar 2019 00:57:38 GMT

Thanks Ian. I am not aware of this awesome JMP feature!

By the way is that possible to change the process performance graph quadrant definition? Seem like by default, the stability ratio set as 1.5 and ppk set as 2.0. How can i change that ? Change the reference line will not change the quadrant.

Re: Cpk Analysis for many parameters

OneNorthJMP — Fri, 22 Mar 2019 01:30:01 GMT

I got it. I can change the boundary by red triangle -> performance graph boundaries.