QMT News: April 2013
Editor’s comment: More is less?

As measurement technology improves, does the the possibility for error grow? This might seem paradoxical. How can an instrument which has improved its measurement specification, perhaps by orders of magnitude, generate more measurement errors?

Well, take a simple gauge, perhaps a micrometer or calliper, now commonly calibrated down to microns: how often do you come across a user reading out a measurement in microns and never questioning the result? Results which may be acceptable if we are talking in millimetres are problematical when it comes to microns, a fact gauge R&R studies often highlight.  The user may not understand the measurement process, the environmental conditions, the sensitivity of the instrument and form of the material being measured etc. to fully achieve an accurate and repeatable result.
But its not just at the simple gauging level that more precision can mean more errors.  Take a sophisticated non contact laser tracker. As the measurement uncertainty specifications supplied by the manufacturer   improve,  the opportunities for creating errors can proliferate. The user can struggle with understanding the results when it comes to applying the technology if he doesn’t understand the principle of metrology behind the technology.

Brendan Coyne
Editor QMT

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