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Chapter 9: C. Gage Selection, Handling, and Use 85
2. Linearity. The accuracy of the measurements of an instrument
throughout its operating range.
3. Magnification. The amplification of the output reading on an instrument
over the actual input dimension.
4. Repeatability. The ability of the instrument to achieve the same degree of
accuracy on repeated applications (often referred to as precision).
5. Resolution. The smallest increment of measurement that can be read on
an instrument.
6. Sensitivity. The smallest increment of difference in dimension that can
be detected by an instrument.
7. Stability or drift. The ability of an instrument to maintain its calibration
over a period of time.
Other selection criteria may include factors such as the shape and size of the
measured part or workpiece, workpiece material, and the capabilities of the metrology
laboratory.
Consideration of these factors, along with cost and operation convenience,
should help in selecting an appropriate measuring or gaging device for a particular
inspection operation. For operating convenience, most instruments are or can
be equipped with discrete digital readout devices. Most of these can be connected
to microprocessors or computers for data recording and analysis.
Part II.C.2
2. GAGE HANDLING, PRESERVATION, AND STORAGE
Identify and apply various methods of
cleaning, handling, and storing gages.
(Application)
Body of Knowledge II.C.2
The following guidelines for the control of measuring and monitoring devices are
taken from Section 7.6 of ANSI/ISO/ASQ Q9001-2000:
• Determine the monitoring and measurement to be undertaken and
the monitoring and measuring devices needed to provide evidence of
conformity of product to determined requirements (see 7.2.1).
• Establish processes to ensure that monitoring and measurement
can and will be carried out in a manner that is consistent with the
monitoring and measurement requirements.
• Where necessary to ensure valid results, the measuring
equipment shall: