CMS CMS Metrology & Measurement Systems 2

Question 1

What is the primary advantage of a Coordinate Measuring Machine (CMM) over manual gauging?

Accepted Answer

Ability to measure complex 3D geometries with high accuracy and generate detailed reports

Answer

CMMs use a precision probe to capture 3D point coordinates, enabling measurement of complex geometries, GD&T features, and automated reporting not possible with manual gauges.

Question 2

Which GD&T (Geometric Dimensioning and Tolerancing) symbol controls the flatness of a surface?

Accepted Answer

⏥ (Flatness)

Answer

The flatness symbol (two parallel lines) specifies that all points on a surface must lie within a tolerance zone defined by two parallel planes.

Question 3

What is gauge R&R expressed as a percentage of tolerance considered 'acceptable' per AIAG MSA guidelines?

Accepted Answer

Less than 10%

Answer

Per AIAG MSA guidelines, a Gauge R&R less than 10% of the tolerance (or study variation) is acceptable; 10–30% may be acceptable; above 30% requires corrective action.

Question 4

A surface finish measurement is reported as Ra = 32 µin. What does Ra represent?

Accepted Answer

Arithmetic mean roughness average of the surface profile

Answer

Ra is the arithmetic mean of the absolute deviations of the surface profile from the mean line, and is the most widely used surface roughness parameter in US manufacturing.

Question 5

What is the purpose of a 'gauge block' (slip gauge) in metrology?

Accepted Answer

To provide highly accurate reference length standards for calibration and setup

Answer

Gauge blocks are precision-ground steel or ceramic blocks with certified lengths used as reference standards to calibrate instruments and set comparators.

(CMS) Certified Manufacturing Specialist Practice Test

(CMS) Certified Manufacturing Specialist Practice Test

CMS CMS Metrology & Measurement Systems 2