CPK / PPK

[#1]

Dear Community,

I have a "simple" question... but it put me in trouble in this moment.

For my analsys I use JMP 14.

 A lot of times I need to calculate CPK and PPK.

When I ask to JMP to calculare the CPK, the software generate this analsys and give me the number.

I checked it and in this CPK number the sigma used for the calculation is "sum of square method" and not R/D2.

So... this rappresent the PPK and not the CPK...

Is it correct?

This create me some confusion in the interpretaion of the process capability.

Do you have some comment or suggestions?

Thanks in advance?

Best Reagrds,

Simone

[#2 · Accepted solution]

Hello,

I just wanted to mention that you can get the same report that Mark is showing in his post in JMP 14 by using the Process Capability platform instead of the Distribution platform.  (The Distribution capability report was updated in JMP 15.)

open("$SAMPLE_DATA\Big Class.jmp");
Process Capability(
	Process Variables( :height ),
	Spec Limits( :height( LSL( 50 ), Target( 60 ), USL( 70 ) ) ),
	Individual Detail Reports( 1 ),
	Capability Box Plots( 0 ),
	Goal Plot( 0 ),
	Capability Index Plot( 0 ),
	Process Performance Plot( 0 )
);

[#3]

Thanks Laural,

also for the details linked to the Version 15 vs Version 14.

Best Regards,

Simone