Accuracy Flashcards
What is precision in measurement?
Measurements should be close to their true values.
Define accuracy in the context of measurement.
The values of measurements should be close to each other (low scatter).
What does uncertainty refer to in measurement?
The statistical dispersion of the values of a measured quantity should be small.
What is resolution in measurement?
The ability to detect small changes in the characteristics of the measurement.
What is calibration?
Measurements using a device should be compared with a calibration standard of known accuracy before use.
Define tolerance in measurement.
The maximum permissible variation in a measured dimension.
What is an engineering rule used for?
To measure linear dimensions with an accuracy of approximately 0.5 mm.
What can a Vernier caliper measure?
It can measure outside diameter, inside diameter, and depth of slots or pockets.
What is the accuracy of a Vernier caliper?
High accuracy to 0.02 mm.
What is the accuracy of an outside micrometer?
Highly accurate to within 0.01 mm.
What is the typical range of an outside micrometer?
Typically comes in various sizes with a 25 mm range, e.g., 0–25 mm, 25–50 mm, 50–75 mm.
What does an inside micrometer measure?
It measures inside dimensions such as the inside diameter of a hole or tube.
What types of inside micrometers are there?
- Caliper-type
- Tubular
- Bore
What is the use of a depth micrometer?
To measure the depth of holes, slots, counterbores, and recesses.
What is the accuracy of a depth micrometer?
Highly accurate to 0.01 mm.
What is a dial test indicator (DTI) used for?
To check for runout when holding a billet in a lathe, check for flatness, and calibrate machines.
What is the accuracy of a dial test indicator?
Extremely accurate to within 0.005 mm.
What are slip gauges used for?
As references for the setting of measuring equipment and to measure slots and grooves.
What is the accuracy of slip gauges?
Used to measure with high accuracy (0.005 mm).
What is the proper use of slip gauges?
- Use the minimum number of blocks possible
- Wring the individual blocks together
- Wipe the measuring faces clean
How do angle gauges differ from slip gauges?
Angle gauges have wringing surfaces that are not parallel and can measure angles between 0 degrees and 360 degrees.
What is the accuracy range of angle gauges?
Accuracy of 0.5 to 0.25 second.
What is the go/no-go gauge design principle?
The ‘go’ gauge covers the maximum metal condition and the ‘no-go’ gauge covers the minimum metal condition.
What is a coordinate measuring machine (CMM)?
A device that measures the geometry of physical objects by sensing discrete points on the surface with a probe.
