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matthewrpenny
 
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Default statistical data, stdev, Pp& Ppk


Hi All

I need a bit of help with a (I think) complicated excel problem.

I am using excel to help keep track of process capability studies
(Checking the capability of a manufacturing process for those that
don't know)

What I have is a drawing dimmension (in this case a diameter) that I
have to measure 30 samples of, i then work out the average, range, and
std deviation, for that point. i then use these figures to work out a
Pp value and/or Ppk value. the difference is that if my spec only has a
lower limit I calculate Pp (ie dia must be greater than X) and if I have
a upper and lower limit I calculate Pp and Ppk (ie dia is between X &
Y), and then using conditional formatting and IF statements show the
results (circle for good, triangle for OK and cross for bad) with both
Pp and Ppk having different criteria

Now it gets complicated!! I could do this easily with two sheets but
TS16949 says that I must use the same sheet for both situations so I
need my sheet to do several things

1. to detect when I am using a lower spec only or an upper and lower
spec and then to select the appropriate equation/set of IF statements
to give the correct result
2. if I am using just lower spec to hide the Ppk Value (grey out/hide
etc..)
AND
3. select the correct Good/OK/Bad criteria.

if anyone thinks they can help PM me and I can show you where I'm upto
on my spreadsheet and maybe it will help you understand.

Thanks in advance for your help
TTFN
Matt


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matthewrpenny
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