Type 1 Gage r study

mahenkj2

Registered
Hi,

I am trying to conduct a study on a wire geometry. Once sample is prepared and fixed at machine, machine can measure the part automatically.

May be very basic questions relating to Type 1 study:

1. Once a part is measured for the first time (after first set up), now for second measurement, would we remove the part and again prepare it for measurement? I believe, Type 1 study is a repeatability study, conducted to be just before detailed Gage R&R, and I assume, we just need to repeatedly use equipment to trigger measurement again and again. We do not disturb the sample piece during the study. By this way, the variation shall be all equipment related and operator caused variations are not in built in the measurements done.

2. AIAG manual describes Gage R & R, but what is the reference for Type 1 study?

Kindly guide on the above matter.
 

Miner

Forum Moderator
Leader
Admin
In the absence of a standard, we have to look at the intent of a Type 1 Repeatability Study for guidance. The intent of the Type 1 study is to remove as many extraneous sources of variation and to focus on the best the gage itself can accomplish. This includes:
  1. Same method,
  2. Same operator,
  3. Same equipment,
  4. Same environmental conditions,
  5. Same location, and
  6. Same item or unit under test.
Given this, I would say that you do not disturb the piece during study. I did find a good explanatory source that does make reference to international standards.
 

mahenkj2

Registered
Thanks a lot. Your text and reference do helps to clear many things.
I have conducted a study based on the above understanding and can interpret the results. I have another questions though after this study:


1. There are specification of some organization of Cg & Cgk >1.33 and %Var(Repeatability) and %Var(Repeatability and bias) <15%, where is that defined, is there any reference manual for such guidelines?
2. there are no Cg and Cgk for one sided tolerance, so how do I interpret the result in that case?

Thanks again.
 

Miner

Forum Moderator
Leader
Admin
  1. I am not aware of any standards, references or guidelines for Cg/Cgk.
  2. The only guidance that I was able to find was for a maximum specification, to use zero as the lower spec. However, I have not had a need to use Cg/Cgk, so my actual experience with it is nil.
 

mtmt70a

Starting to get Involved
Two Standards you might want to review for a Type 1 MSA Gauge Study: VDA-5 and ISO-22514-7. We are completing our 1st for testing a Drive Component. Make sure you understand what the Customer is needing, and review any possible Modification they might have with the Cg and Cgk calculations esp. around how "k" is defined around the number of Std. Deviations used to represent the normal Dist. spread.
 
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