Metrology

Syllabus

1. Introduction (1 hour)
   1. Definition, concept, need and importance of metrology
   2. Types of metrology (industrial, legal, dynamic and deterministic)
   3. Classifications of measuring methods
   4. General metrological terms: accuracy, precision, repeatability, reproducibility, sensitivity, resolution and stability
2. Measurement Errors and Uncertainty (2 hours)
   1. Sources of measurement errors
   2. Classification of errors: systematic, random, and gross errors
   3. Uncertainties: types, related calculations on uncertainties
   4. Line of best fit
   5. The effects of averaging results
3. Standards of Measurements (3 hours)
   1. Introduction
   2. Material standards
   3. Wavelength standard
   4. Sub-division of standard
   5. Line and end measurements
   6. Calibration of instruments and traceability
   7. Nepal bureau of standards and metrology (formation, duties and responsibilities)
4. Linear, Angular and Taper Measurement (6 hours)
   1. Instruments for linear measurements: vernier calipers, micrometers, vernier height gauge, vernier depth gauge, slip gauges, dial indicators, combination set
   2. Instruments for angular measurements: bevel protractors, sine bar, sine table, sine centre, angle gauges, spirit level, clinometers, auto-collimator, angle dekkor
   3. Gauges for taper shafts
   4. Measurement for taper shafts and holes
5. Comparators (3 hours)
   1. Basic principle of measurement
   2. Classification of comparators
   3. Advantages and disadvantages of various types of comparators
6. Interferometry (2 hours)
   1. Introduction
   2. Principle of interference
   3. Light source for interferometer
   4. Optical flat
   5. Types of interferometers: configurations, applications and working methods
7. Limits, Fits and Tolerances (5 hours)
   1. Basic terminology related to limits, fits and tolerances
   2. Types of fits: interference, transition and clearance fits
   3. ISO system of limits and fits
   4. Selection and calculation of fits and tolerances
   5. Principle of interchangeability
   6. Selective assembly
   7. Fundamentals of geometric tolerances: tolerances on shape or form, tolerance on orientation and tolerances on position
8. Gauges (4 hours)
   1. Classification of plain gauges
   2. Taylor's theory for gauge design
   3. Gauge design of workshop gauge, inspection gauge and general gauge (first, second and third system)
   4. Gauges for tapers
   5. Related problems on limits, fits and tolerances, selective assembly and gauge design
9. Measurement of Surface Finish (3 hours)
   1. Factor affecting surface roughness
   2. Reasons for controlling surface texture
   3. Orders of geometrical irregularities
   4. Elements of surface texture
   5. Evaluation of surface texture
   6. Surface roughness measurement techniques
   7. Related problems on surface roughness measurement
10. Gear Measurement (3 hours)
    1. Gear tooth terminology
    2. Measurement and testing of spur gears
    3. Tooth thickness measurement
    4. Measurement of pitch, concentricity, run out and involute profile
    5. Tooth bearing contact testing
    6. Composite method of gear testing
11. Measurement of Screw Threads (3 hours)
    1. Terminology of screw thread
    2. Errors in threads
    3. Effects of pitch errors
    4. Measurement of major diameter, minor diameter, pitch, angle and effective diameter of screw threads by 2-wire and 3-wire methods
    5. Calculation of best wire size
    6. Screw thread gauges
12. Acceptance Tests for Machine Tools (2 hours)
    1. Introduction to acceptance tests
    2. Equipment required for geometrical tests
    3. Alignment or geometrical tests of machine tools
    4. Performance test
13. Measuring Machines (2 hours)
    1. End bar measuring machine
    2. Universal measuring machine
    3. Coordinate measuring machine (CMM)
    4. Computer controlled coordinate measuring machine
14. Quality Control Management (6 hours)
    1. Quality, quality control, quality assurance, total quality control, quality circle, total quality management, ISO 9000 series of quality system
    2. Statistical quality control in engineering production: process variability, process capability, control charts, sampling inspection
    3. Sampling plan
    4. Related problems on statistical quality control (standard deviation, normal distribution, probability, control charts)

Practicals

1. Mechanical component measurement using vernier caliper, micrometer and vernier height gauge
2. Determination of unknown angle using spirit level, bevel protractor and sine bar
3. Spur gear measurement using vernier tooth caliper
4. Calibration of micrometer using slip gauge
5. Study and use gauges: filler, radius, thread, wire, Go and No-Go gauges
6. Performance on measurement of screw thread
7. Performance on surface finish measurement
8. Study on the effect of cutting variables on surface roughness
9. Measurement of straightness, flatness and roundness
10. Alignment test on lathe, drilling and milling machine
11. Experiment to measure process capability using statistical process control