Choosing Parts for Attribute MSA (Measurement System Analysis) in 4th Edition, pg 132

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Stevenli

Folks,

When go through the 4th Edition MSA manual for attribute MSA in terms of part choosing, one question comes out is it just mentioned that select 25% parts at or close to LSL and 25% at or close to USL. How about another 50%? My understanding is can be 25% as good one and last 25% as defective parts.

Does anyone have some good clues?

In 3rd edtion, I just use 33% good, 33% defects and 33% as marginal.

Thanks.
;)
 
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David DeLong

Re: Choosing the Parts for Attribute MSA (Measurement System Analysis) in 4th Edition

I just have been going through the 4th edition myself and sample selection has been contentious item even in this forum. Here is what it says on page 74 "the sample parts must be selected from the process and represent the entire production operation range".

I don't know where you got the information of the 25% selected near both the upper & lower SL. I couldn't find that information.

I would run a 30 piece capability study and then select my 10 samples from that study making sure that the highest and lowest values found in the sample along with other samples were utilized for R & R study. These parts could be inside the spec limits or outside since we are utilizing samples from the process rather than the specification limits.

Hope this helps.
 
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Stevenli

Re: Choosing the Parts for Attribute MSA (Measurement System Analysis) in 4th Edition

David,

Thanks, I am talking the samples for attribute MSA under Risk analysis section in Page 132. Could you review that to understand that more.

Thanks.
 
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