max. tool measurement uncertainty vs gauge size

[cervantes]

Hi,

When a manufacturer says in datasheet that measurement uncertainty of 150mm (resolution 0.01) caliper is +.- 0.03 mm - then is it applied to a maximum measured size or also to for e.g. 24 mm?

I want to check myself measurement uncertainty of my 150mm caliper using standard deviation techniques to estimate dependency of measurement uncertainty vs size of measured detail (naturally using precision gauges block of different sizes) but first of all I wanted to know if someone has any experience with this kind of question?

 

[IRstuff]

That depends on the manufacturer. Uncertainties can be specified as relative to the actual measurement or to full scale.

TTFN
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[RolMec]

for a mechanical measurement principle precision caliper the error might be given either
- on a percentage basis: then your assumption about the dependance from the measured size is correct. The manufacturer would thus include a size dependance of the measurements precision.
- or as an absolute value: then the manufacturer states that the measurement error caused but by the mechanical device is (to a certain defined probability)within +/- x units of length

If your device's mechanical drive is a gear or a screw thread, then it is probable that this mechanical appliance has an error which would be adding up when measuring larger sizes.
So, the solution would be that you choose different gauges and set up sufficiently representative series of measurements in order to apply statistics and get the overall picture.


RSVP