Gage R&R Procedures: Selecting parts (sample) to measure

G

grs2828

Hello,

I am fairly new to Gage R&R studies, and I need to perform one on an analytical balance used mainly to weigh tablets. There are about 5 different kinds of tablets that are normally weighed in this balance (different sizes and weights). I understand that for the study I should select tablets that are representative of the usual variation, which i interpret means that if a tablet's target weight is 0.1g but varies from 0.096 to 0.15, i should pick tablets that cover that range. My confusion is, should i pick one type of tablet and select 25 (or however many is necessary) samples of the same tablet, ensuring that they cover that range, or should i pick tablets from the five different kinds?

Thank you for your help!

~Gabriela
 

Miner

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Admin
For what purpose is the balance used?

If you use it to inspect only, the selection of samples for R&R is not critical. It is only when you use it for process control (e.g., SPC) that the parts must represent the process variation.

If the balance is used for process control, representative process variation is that variation for one specific nominal weight.

The different nominal weights may be checked using a linearity study.
 

bobdoering

Stop X-bar/R Madness!!
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Many better balances have stabilization software features, which can effect the repeatability. Be sure to check out your scale to see if this is handy feature is available.
 
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