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SPC computing using un-natural pattern (WPT/BST/DST)

Kelvinjay

Community Member

Joined:

Feb 3, 2017

Hi,

 

I will be glad if anyone can share how to re-compute the spc data, objective- i want to loosen up the UPL and LCL

 

will appreciate any suggestions. Thanks!

2 REPLIES
txnelson

Super User

Joined:

Jun 22, 2012

I am not totally confident that I understand what you are asking, but I will give it a shot.  My assumption is that you want the SPC charts to use a different algorithm to calculate the upper and lower confidence limits, and then to use those values for the displaying on the SPC chart.  While the Control Chart platforms use a preset algorithm for the calculation, you can calculate whatever limits you want, outside of the Control Chart platforms, and then apply those limits to the process variable, as a column property, and then when the platform is run, it will use the embedded control limits.  Is this what you are looking for?

Jim
markbailey

Staff

Joined:

Jun 23, 2011

What is the basis for your alternative limits?

You can also change the default k=3 sigma mulltiplier when JMP computes the limits for you. Alternatively, you can also change to probabilty limits for any probability level that you want to use. These options are not available in Control Chart Builder but they are available in the legacy Shewhart control chart platforms.

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