Is Minitab technical support answer 2255 wrong?

[Brian Dowsett]

Hello cove people
I am looking into Type 1 gauge studies and found my way onto the minitab technical support site.
Could someone take a look at anser 2255 for me and tell me if i'm going nuts?

Page 2, talking about a study of a gauge used on a process with top limit only
gives a formula to calculate the control limit which I can't make sense of (shouldn't the factor used be 'L' which is the number of Std Dev's to be used in the gauge study) ??

Then it says that the measurements should be ABOVE that limit. Shouldn't the limit (which I think is normally 4 gauge std devs) sit below the process top limit and measurements should be below that?

Also does anyone have an opinion on calculation of Cg and Cgk when a gauge is used on a single sided process?

Thanks

Brian

[Scott Catron]

Bumping to see if anyone can offer some help.

[Yanling]

Hi Brian,

There are three typos in the last paragraph of page 2. which have been corrected.

1. K should be replaced by L.
2. For lower spec limit only, replace words “less than” by “greater than”.
3. For upper spec limit only, replace words “greater than” by “less than”.

Sorry about this. Thanks for raising the question.

Yanling

[Miner]

Originally Posted by Yanling

Hi Brian,

There are three typos in the last paragraph of page 2. which have been corrected.

1. K should be replaced by L.
2. For lower spec limit only, replace words “less than” by “greater than”.
3. For upper spec limit only, replace words “greater than” by “less than”.

Sorry about this. Thanks for raising the question.

Yanling

Welcome to the cove, and thank you for responding. I presume that you are associated in some manner with Minitab, since Answer ID 2255 was indeed modified yesterday. If you are, we get a fair number of questions regarding Minitab, and your support would be welcome.

[Brian Dowsett]

Thanks to all for taking time to help.

The other part of the answer on minitab technical support (my question number 885596) said there is no methodology to calculate Cg or Cgk when a single sided tolerance is used.
I'd instictively think that Cgk could be calculated and used in the normal way but i'm not sure about Cg.
Does anyone have experience or an opinion on this?

Cheers

Brian

[Miner]

Bumping post.