The Elsmar Cove Business Systems and Standards Discussion Forums Cp vs. Cpk - A Visual Animation and Related Discussion Threads
 Forum User Name Keep Me Logged In Password
 Register Photo Albums Blogs FAQ Registered Visitors Social Groups Calendar Search Today's Posts Mark Forums Read

 Elsmar Cove Forum Visitor Notice(s)

# Cp vs. Cpk - A Visual Animation and Related Discussion Threads - Page 2

 Monitor the Elsmar Forum Courtesy Quick Links Links Elsmar Cove visitors will find useful in the quest for knowledge and support: Howard'sInternational Quality Services International Standards Bodies - World Wide Standards Bodies International Organization for Standardization - ISO Standards and Information Quality Digest

Post Number #9
12th January 2015, 02:01 AM
 reynald Total Posts: 283
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

For analysis yes because it would be very meaningful to compare them.
Case 1: Cp = 1.5, Cpk = 0.98 --> your problem is centering
Case 2: Cp = 0.98, Cpk = 0.98 --> your process is perfectly centered, your problem is variation
 Thank You to reynald for your informative Post and/or Attachment!

Post Number #10
12th January 2015, 02:32 PM
 Bev D Total Posts: 3,614
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

and of course, a simple look at the data will tell you the same thing and a whole lot more. no need to go through the calculations (unless of course your customers are requiring the numbers.)
Post Number #11
12th January 2015, 03:32 PM
 Mikael Total Posts: 214
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

Lol good point, but what if I want to see some kind of trendanalyze over time, then the numbets would be nice?
Post Number #12
12th January 2015, 04:02 PM
 Bev D Total Posts: 3,614
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

yes of course the actual numbers would be useful. trend the data not the Cp/Cpk index. a simple run chart of multi-vari is the best place to start, then you can add statistical control limits.

W. Edwards Deming said it best: "plot the bloody dots". in other words, forget the math, plot the data.
 Thanks to Bev D for your informative Post and/or Attachment!
Post Number #13
12th January 2015, 05:19 PM
 LUV-d-4UM Total Posts: 769
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

Bev,
I like your comment. We do 100% inspection. But the TS auditor wants to see trending chart. So we just comply.
Post Number #14
13th January 2015, 05:08 PM
 Mikael Total Posts: 214
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

Reynald: for case 2 did you mean cpk 0,98???
Post Number #15
15th January 2015, 12:32 PM
 reynald Total Posts: 283
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

What I meant is that if your Cp failed then you sure have variation issues.
If Cp is good and only Cpk failed, then the problem could be easier as you need only to do some centering adjustments (centering a process is not always easy but more often easier than reducing variation).

Note that case 3 where Cp<Cpk dont exist. Cpk can only be as high as Cpk and that occurs when mean is perfectly centered.
 Thanks to reynald for your informative Post and/or Attachment!
Post Number #16
9th April 2018, 04:10 AM
 Zk_Shazly Total Posts: 1
Re: Cp vs. Cpk - A Visual Animation and Related Discussion Threads

CP indicates the consistency of the process whatever if it achieves its target or not
CPk indicates both consistency & achieving target of the process

 The Elsmar Cove Business Systems and Standards Discussion Forums Cp vs. Cpk - A Visual Animation and Related Discussion Threads

 Bookmarks

 Visitors Currently Viewing this Thread: 1 (0 Registered Visitors (Members) and 1 Unregistered Guest Visitors)

 Forum Posting Settings You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Emoticons are On [IMG] code is On HTML code is Off Forum Rules

 Similar Discussion Threads Discussion Thread Title Thread Starter Forum Replies Last Post or Poll Vote Marc Document Control Systems, Procedures, Forms and Templates 14 30th September 2013 02:59 PM fallon Forum Software - How to Do Things in the Elsmar Forum --> Instructions 6 27th August 2009 06:45 PM Marc Document Control Systems, Procedures, Forms and Templates 2 3rd July 2009 08:23 AM harry Forum News and General Information 21 3rd January 2008 01:10 PM Marc Document Control Systems, Procedures, Forms and Templates 0 1st October 2006 03:34 PM

The time now is 09:52 PM. All times are GMT -4.