R
Riverbend
Thus the term verify rather than calibrate
These definitions are rather academic - with no one definition being held as the "final answer". For example AIAG defines calibration as:
A set of operations that establish, under specified conditions, the relationship between a measuring device and traceable standard of known reference value and uncertainty. Calibration may also include steps to detect, correlate, report or eliminate by adjustment any discrepancy in accuracy of the measuring device being measured.
So, adjustment is an option for calibration not a requirement.
The term verification is more typically used when placing a standard in a device in operational conditions, not necessarily controlled conditions, such as mastering a gage on the shop floor.
But, outside of the academic definitions, the bottom line is that it doesn't matter what you call the process, just that you do it correctly to ensure the measurement system is actually correct. The goal is to never have the excuse that you sent non-conforming product “because the gage was off and you didn’t know it.”
R
Riverbend
Agreed, that is the bottom line.
Thanks for the replies. It was getting expensive "calibrating" the tapes, and steel rules that we were "verifying" to so we are having employees buying a brand tape that we have received a manufacuring tolerance on, anf will save us some $$ in the long run. I have been a mmember of this forum for a while & have learned so much in the replies, first time I've posted & I just want to say I appreciate your input on this and other matters myself & Co. had questions on. 
Kyle, I appreciate you jumping in! 
Even on subjects like this that we have had discussion on before, it's always nice to get a fresh perspective on things.
One of these days we will all have bionic eyes, and no verification, tape measures or rulers will be needed!
But until then, I guess we'll struggle with the tape measure/ ruler to be or not to be question.
Even on subjects like this that we have had discussion on before, it's always nice to get a fresh perspective on things. One of these days we will all have bionic eyes, and no verification, tape measures or rulers will be needed!
But until then, I guess we'll struggle with the tape measure/ ruler to be or not to be question.
Wow... This thread was started in January 2007 and has 156 posts (as of the date of this post). This is the post that started the thread:
Admittedly this is a *long* discussion thread. I looked and it has been viewed over 47,242 times.
Pretty much sums it up, but the discussion is good in that so many people have trouble with defining the "...legitimate reason..." part in their specific scenario.
Admittedly this is a *long* discussion thread. I looked and it has been viewed over 47,242 times.
R
Riverbend
The steel rule will probaly the be the only thing you can purchase with Calibration records, therefore it can be used to verify the painted lines on the tape measure are in the right place, wtite in your cal/verification p[rocedure to alwats spot 1" to get around the sloppy sliding end of the tape.
You wouldn't use a tape to measure something with a .030 tolerance anyway, the lines are wider than that, but for +/- 1/8" or so, this system has passed all by 3 Regulatory auditing agencies since 1998, and that is good enough for me if they are all happy, some were actually impressed that someone actually did something to adress tape measures in a business where some larger tolerances allowed its use.
You wouldn't use a tape to measure something with a .030 tolerance anyway, the lines are wider than that, but for +/- 1/8" or so, this system has passed all by 3 Regulatory auditing agencies since 1998, and that is good enough for me if they are all happy, some were actually impressed that someone actually did something to adress tape measures in a business where some larger tolerances allowed its use.
W
WilBryan
ok, so here is our solution to the issue. Im not saying it is correct, just what we have come up with so far. I would appreciate some thoughts or critique as this is currently a hot button issue (post audit).
All of our critical measurements of materials are routed through our QC department and have calibrated devices used to determine accurate dimensions. It is documented in our SOP's that any unmarked device is a "for reference" only tool (saving us any stickers) and that "for reference" devices may only be used for non-critical or approximate measures. Our SOP's also outline that any measurement or cut made in the assembly area is a non-critical measure and should be considered a call for the technician to 'cut to fit'. If there is question about the tolerance of spacing or a cut, there is a provision for taking the part to QC for verification or an engineer for confirmation of the measure and calibrated devices can be checked out of QC if it is needed for a specific purpose on the assembly floor.
In your opinions, does this cover the subject?
Wil Bryan
“It will be difficult to improve until we all start doing it wrong the same way.”
All of our critical measurements of materials are routed through our QC department and have calibrated devices used to determine accurate dimensions. It is documented in our SOP's that any unmarked device is a "for reference" only tool (saving us any stickers) and that "for reference" devices may only be used for non-critical or approximate measures. Our SOP's also outline that any measurement or cut made in the assembly area is a non-critical measure and should be considered a call for the technician to 'cut to fit'. If there is question about the tolerance of spacing or a cut, there is a provision for taking the part to QC for verification or an engineer for confirmation of the measure and calibrated devices can be checked out of QC if it is needed for a specific purpose on the assembly floor.
In your opinions, does this cover the subject?
Wil Bryan
“It will be difficult to improve until we all start doing it wrong the same way.”
Crusader
Trusted Information Resource
:truce:
100% of our final products are accepted/rejected using steel tape measures. We use the entire tape a lot of times to measure. Tape measures are various lengths but most are 25'. We're allowed up to +/- 1/2" tolerance when measuring the final product.
There are hundreds of measuring tapes all over the place that are not verified/calibrated, etc.. :mg:
My task is to verify all of them and put in a "calibration system". Can I simply buy a "master" tape and use that as its sole purpose for verifying all of the others out in use? Would that master need to go out to a certified lab to get "certified"??
Can it be that simple? The master steel tape measure does not have to be traceable to NIST, right?
:truce: Guidance please - much appreciated!!
oh yeah, there is no qc lab, no dept., etc. These steel tapes will be verified in the environment where used. I am the lab. I am the qc/qa dept. LOL!
and all of this must meet ISO 9001:2008 requirements.
Last edited:
