Hi Ron & Team :

if you are still looking for a handy formula , here it goes : (paste the
formula to an excel sheet and play around ; substitute DPMOp with the name
of your DPMOp cell ).

SIGMA =
6.28-0.000001*DPMOp-0.223*LN(DPMOp)+0.00162*(LN(DPMOp))^2-0.000672*(LN(DPMOp
))^3

Note :

* = multiply
LN = natural logarithm
^ = to the power of

DPMOp is Defects Per Million Opportunities .
DPMOp = DPM / OFE
DPM = PPM = DEFECTS PER MILLION
OFE = OPPORTUNTIES FOR ERROR =  the number of ways you can screw up a
process !
For example  a typical passive component soldering has an OFE of 3.

1. You don't place the part
2. Your one lead is unsoldered etc.
3. Your other lead is unsoldered etc...

If your soldering is perfect, you have avoided 3 OFEs !!!!

ps : did i really help here ? :) Maybe I opened the can of OFE worms !!!!

Vishy Narayana.

-----Original Message-----
From: Hollandsworth, Ron [mailto:[log in to unmask]]
Sent: Tuesday, February 08, 2000 9:41 PM
To: [log in to unmask]
Subject: [TN] Subj: Six Sigma


Good Morning TechNetters!
Here is a brain teaser for this early morning.  Thinking six sigma.  Six
sigma is suppose to be 3.4 PPM.  Good!  Now what is five sigma, four, three,
two , one.  There is a chart that shows that relationship of a certain sigma
and the PPM associated with that particular sigma value.

Ok, the first five to get the right answer will be eligible to go on to the
"Who wants to be a Black Belt" show.  Enough levity, can someone help me
out.  Do you know the chart I am referring to?  Can you send me the values
and I'll make a chart.

Grasshopper Ron

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