CMS Metrology & Measurement Systems Flashcards
6 cards from real CMS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CMS Metrology & Measurement Systems flashcards as text
What is the purpose of a 'calibration interval' in a manufacturing measurement program?
Answer: To define how frequently a measuring instrument must be re-calibrated to ensure continued accuracy
Calibration intervals specify the maximum time or use between calibrations, ensuring instruments remain within acceptable accuracy limits throughout their service life.
Which measurement technique uses air pressure drop to determine the size of bores and other internal features?
Answer: Air gauging (pneumatic gauging)
Air gauging measures the back-pressure or flow rate of air escaping through the gap between the gauge and the part surface to determine dimensions with high sensitivity.
In GD&T, what does MMC (Maximum Material Condition) mean for an external feature like a shaft?
Answer: The shaft is at its largest allowable diameter, where maximum material is present
MMC for an external feature (shaft) is the condition where it contains the most material, i.e., at its largest permissible diameter.
What is the 10:1 gauging ratio rule in metrology?
Answer: The measuring instrument's resolution should be at least 10 times finer than the tolerance being measured
The 10:1 rule states that a gauge's discrimination (resolution) should be at least 1/10 of the part tolerance to ensure measurement uncertainty is small relative to the tolerance.
Which optical instrument projects a magnified silhouette of a part onto a screen to compare it against a master overlay template?
Answer: Optical comparator (profile projector)
An optical comparator magnifies a part's shadow profile and projects it onto a screen where it is compared to a precise overlay chart to check contours and dimensions.
What does 'linearity' describe in a measurement gauge's performance characteristics?
Answer: The consistency of bias (systematic error) across the full operating range of the gauge
Linearity evaluates whether the gauge's bias (difference between measured and reference value) remains consistent or changes systematically across its measurement range.