This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Universal Measuring Machine”.
1. What is the difference between CMM and UMM?
a) UMM can’t inspect geometrical features while CMM does it
b) CMM is more accurate than UMM but can’t inspect geometrical features
c) UMM is more accurate than CMM and can inspect geometrical features
d) CMM is more accurate than UMM but can’t inspect geometrical features
Explanation: Co-ordinate measuring machine doesn’t inspect the geometric features of the part but universal measuring machine does it. Co-ordinate measuring machine is less accurate than a universal measuring machine.
2. Which type of standard is UMM for calibration of hole location gauges?
a) Primary standard
b) Secondary standard
c) Basic standard
d) Reference standard
Explanation: Universal measuring machine is a primary standard for calibration of hole location gauges. A hole-location gauge is calibrated on universal measuring machine and used to inspect a Co-ordinate measuring machine.
3. Which of the following is used to locate awkward shaped workpieces in UMM?
a) Swinging table
b) Tilt table
c) Rotary table
d) Angular table
Explanation: The workpieces of awkward shape can be located by using a rotary table to align reference holes with the measuring axes. When the dimensions are specified with respect to centre hole in the part, then initial line-up is facilitated by using the reference hole in the rotary table centre.
4. Which of the following is used to measure macro-circuit components in UMM?
c) Probe tip
Explanation: For measuring the location of small holes, a microscope is used and also for parts which are damaged by physical contact. Parts like components of macro-circuit, which doesn’t have reference surfaces against which an indicator probe-tip may register, can be measured by a microscope.
5. Which of the following are the foundations of mechanical accuracy in UMM?
a) Geometry and length
b) Roundness, geometry and length
c) Geometry, division of circle and length
d) Roundness, geometry, division of circle and length
Explanation: “Cubic concept” of accuracy in the UMM requires the individual mastery of 4 mechanical arts-Roundness, geometry, division of circle and length. These are the “Foundations of Mechanical Accuracy” truly.
6. Which of the following option is true for given statements about UMM?
Statement 1: Measurement on CMM is faster than UMM.
Statement 2: UMM can resolve the exact nature of error of features of all parts.
a) T, T
b) F, T
c) T, F
d) F, F
Explanation: Universal measuring machine is capable of resolving the exact nature of the error of features of all parts. This machine discloses information about measurement which in turn permits the machine or methods improvement.
7. Which of the following principle is used to derive authority for angles of angle gauges or angular relationships in mechanical parts and assemblies?
a) Self-assessment principle of dividing the circle
b) Self proving principle of dividing the circle
c) Self verification principle of dividing the circle
d) Self explaining principle of dividing the circle
Explanation: Accurate circle division is a requirement of all machine shops and laboratories. The self-proving principle of dividing the circle is used to derive the authority for “angles” of angle gauges, rotary tables, or the angular relationships in mechanical parts and assemblies.
8. Which of the following is the authority for roundness?
a) Precision spindle
c) Dividing circle
d) Rotary tables
Explanation: It is important to achieve roundness for precision machine tools of many mechanical parts and with their spindles especially. A precision spindle is an authority for roundness.
9. Which of the following is not true for UMM?
a) Less skilled operator is needed
b) It is a slow machine
c) Used as a special purpose machine in metrology laboratories
d) A valuable machine for comparing master gauges and length standards
Explanation: UMM is a slow machine. It requires a highly skilled operator to use. The accuracy created in these machines has overcome the needs of most industries. As a result, today UMM is only found as a special-purpose machine in metrology labs.
10. Which of the following is a foundation of all geometrical accuracy?
a) Vertical plane
b) Flat plane
c) Rough plane
d) Oblique plane
Explanation: The foundation of all geometric accuracy is the flat plane. Meehanite cast iron is a prime material component for the elements of geometry because it is available readily, easily cast to shape and relatively uninfluenced by relative-humidity.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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