Sloping control chart to take care of tool wear - Details needed

B

bkarthikeyan

I need to know the methodology for plotting the Sloping control chart ( to take care of tool wear )preferably with an example

thanks in advance
 

Bev D

Heretical Statistician
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"Can I Have Sloping Limits" Dr. Donald Wheeler, Quality Magazine, May 1999

“Process Control and Evaluation in the Presence of Systematic Assignable Cause”, Ashok Sarkar and Surajit,Pal, Quality Engineering, Volume 10(2), 1997-1998

Also look for Bob Doering's blogs on the uniform distribution here at the cove.
 

bobdoering

Stop X-bar/R Madness!!
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This tread is good,check for the attachment I posted there, Its Dr Wheeler article.

The attached Selden article was a particularly good use for the sloping control chart, as it expects the slope to continue. This process is not as applicable to tool wear, as adjustments are expected (or the dimension would increase infinitely). The issue is not events that are relevant to the slope, but the slope itself, as the main variation for a process affected by tool wear, and adjustment based on it. It would also miss controlling the effect measurement error, giving false process variation. That is why for tool wear I recommend the X hi/lo-R methodology, as it deals with all of these effects, as well as deals with the correct uniform distribution - which the sloping chart also misses altogether. :cool:
 
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