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April 1998

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Subject:
From:
Don Vischulis <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Sun, 19 Apr 1998 12:39:14 -0500
Content-Type:
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Dave:

I too am not entirely clear on Paul's statement, but part of a GR&R study deals with operator
effects.  In a GR&R study the same instrument is used by different operators.  You can imagine
that a caliper might have slightly different test results depending on whether the measurements
are taken with the tips or the center of the measuring jaws and whether an inside or outside
measurement is taken.  In the same manner, GR&R for an instrument like the wave rider might be
dependent on external (to the instrument) factors.

Perhaps Paul can expand on the limitations experienced in attempting to GR&R for the instrument.

Don Vischulis
------------------------------------------------------------
David D Hillman wrote:

> Hi Paul - I am confused by one of your statements - " GR&R is intended to
> evaluate the
> entire process: the machine, the measurement tool, and the operators." My
> understanding of the use of GR&R (as I have been brainwashed by our local
> statistical terrorist) is to evaluate the measurement tool for its inherent
> accuracy and precision. For example, I would test a wetting balance's GR&R
> by using the test method procedure and a standard sample, preferably
> something such as a NIST standard or I would test a surface mount placement
> machine by placing components on a calibrated, standard grid board, etc.
> The ANSIJ-STD-002/003 committees have been successfully using GR&R to
> assess or setup criteria that the measurement devices must have before you
> would use them in a test -  the theory is can you must be able to
> distinguish the signal you want to measure from the noise surrounding it
> and then apply the measurement to the system you want to understand. If you
> can't separate the signal from the noise then don't bother making the
> measurement. You should be able to obtain a GR&R for the WaveRider if you
> could measure it against a known temperature source and/or a known conveyor
> speed standard.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
> [log in to unmask] on 04/17/98 06:12:04 PM
>
> Please respond to [log in to unmask]; Please respond to
>       [log in to unmask]
>
> To:   [log in to unmask]
> cc:    (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
> Subject:  [TN] Assy:WaveRIDER Gauge R&R
>
> I read a quick question about WaveRIDER as to whether a Gauge R&R Study has
> been done and have the following to offer:
> We (the Manufacture) looked into GR&R as a possible means to "qualify" the
> validity of the measurements made by the WaveRIDER and elected NOT to use
> this method because it seems to apply best to a very limited set of
> condition not necessarily represented by a WaveRIDER. Combine that with
> limited understanding of GR&R (except those who have made it their ambition
> to understand it) and what the results really mean, we found they would
> only serve to confuse general users. Also, GR&R is intended to evaluate the
> entire process: the machine, the measurement tool, and the operators. Thus
> any results we get would only represent our process, and any results you
> get your process, and so on. We have, however, done some Cpk studies on the
> WaveRIDER's various measurement parameters which yielded values 1.5 and up,
> depending on the measurement. These studies served only to prove that our
> specs for the WaveRIDER are valid. In general, the WaveRIDER measures
> temperature within +/-1 degree C and time to 1%+/-0.1 seconds.
> Thanks for the question.
> ^^^^^^^^^^^^^^^^^^^^^^^^^
> Paul Austen
> Project Engineer
> New Product Introduction Team
> ECD Inc
> 4287A SE International Way
> Milwaukie OR 97222
> Phone: 503.659.6100
> Fax: 503.659.4422
> Email: [log in to unmask]
> Web: www.ecd.com
> ^^^^^^^^^^^^^^^^^^^^^^^^^

snip the rest --------------------------------------------------

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