1. Metrology and Computer Aided Inspection (MEng 6223)
Lecture on
Introduction
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2. MEng 6223 Metrology and Computer Aided Inspection
Syllabus/course content:
Introduction to Metrology
Fundamentals of dimensional Measurement
Length Standards
Fits and tolerances
Application of light Interference for precision measurements
Concepts and practice of gauging
Comparators and their applications
Linear and angular measurements
Thread and gear inspection
Form, flatness, straightness and alignment measurements
Surface metrology
Co-ordinate metrology
Laser applications in metrology;
Vision inspection/ Aid Computer Inspection
Micro and nano metrology.

3. MEng 6223 Metrology and Computer Aided Inspection
Text Books:
Reference Books
Shotbolt, C.S. and Galyer. J., Metrology for Engineers,
5th ed., Cassell Publ. (1990).
Anand K Bevoor, Vinay A Kulkarni, Metrology and Measurement, Tata Mc Graw-Hill.
Jain R.K., Engineering metrology, Khanna Publications
Busch., Fundamentals of Dimensional Metrology, Delmar Publishers (1998)

4. Learning Objectives of Metrology
To understand the role of metrology in manufacturing and its value addition
To learn about measurement concepts and sources of error in measurement
To learn methods of measurement and evaluation for dimensions, form and finish of manufactured components
To learn and appreciate the usefulness of Manufacturing metrology

5. Introduction What is Metrology? Why Precision Length Measurements?
Need for reliable Standards.
Standard of Length.
Shop floor standards.
Traceability.

6. What is Metrology ? Metro - logy
from Greek 'metron' [measure], and –logy 
Meaning Measurement Science
Thus, deals with atmosphere and weather condition,
deal with science of weight and measure
In English, the term Metrology is often used for Measurements 
Engineering Metrology
Industrial Metrology
Dimensional Metrology
  Manufacturing Metrology

7. What is Metrology? Metrology is the science of measurement
The Science Behind Quality Control IN A Manufacturing Shop Floor
Metrology is the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology.
And also ”International Bureau of Weights and measurements (BIPM)”

8. Why do you need Metrology ?
The purpose of engineering design is to convey information in a way that makes it as easy as possible for the manufacturing team to create the desired parts and assemblies.
The design intent,
the people and processes involved in manufacturing,
The inspection and verification process
Benefits
Quality - Good engineering drawings result in parts that match the design intent. Budget - Getting a drawing right the first time saves money.
Time - When dimensions and tolerances are stated clearly and thoroughly, manufacturers do not need to take the time to ask questions or get clarification.
Customer satisfaction - Producing the correct results in a timely manner keeps customers happy.

9. Why you need Metrology ?
It is the technology behind the quality assurance processes in manufacturing
Verifying and validating the design specifications
National and international trade increasingly require demonstrated conformity to written standards and specifications with mutual recognition of measurements and tests, i.e. worldwide traceability of measurement results to the SI
Assessing the capability of machine tool and controlling the manufacturing process
Economic success of most manufacturing industries is critically dependent on how well products are made, a requirement in which measurement plays a key role.

10. An individuals life journey begins with measurement and end with measurement

11. Areas of Application of Metrology

12. Measurement
Measurement encompasses different fields such as communications, energy, medical sciences, food sciences, environment, trade, transportation, and military applications
Measurement is an act of assigning an accurate and precise value to a physical variable
The physical variable then gets transformed into a measured variable
Meaningful measurements require common measurement standards and must be performed using them
Measurements provide a basis for judgements about process information, quality assurance, and process control

13. Manufacturing Industry
Dimensional inspection
Quality control

14. Space Stations, Satellites
Metrology laboratories test standards for many companies that provide parts of the space shuttle
These parts include the metal, heat shield, electronics, fabrics, o-rings, optics, and tires

15. Defence Industry
Metrology laboratories test standards for many military and defense companies
These companies make the guidance systems for the Patriot missiles and other things that are top secret

16. Pharmaceutical Industry
Metrology laboratories test weights and volume standards for pharmaceutical companies
Products include medicines like aspirin, antibiotics, vaccines, insulin, & vitamins

17. Types of Metrology Scientific Metrology Industrial Metrology
Legal Metrology

18. Scientific Metrology
Organization and development of measurement standards and their maintenance (highest level)
NIST Atomic Clock
Accurate to 1 s in 20 million years

19. STANDARDS of MEASUREMENTS
The yardstick (Henry I, thumb to nose)
In A.D the king of England decreed that the standard of length in his country would be named the yard and would be precisely equal to the distance from the tip of his nose to the end of his outstretched arm.
Similarly, the original standard for the foot adopted by the French was the length of the royal foot of King Louis XIV.
This standard prevailed until 1799, when the legal standard of length in France became the meter, defined as one ten-millionth the distance from the equator to the North Pole along one particular longitudinal line that passes through Paris.

20. Industrial Metrology
Adequate functioning of measurement instruments used in industry as well as production and testing processes

21. Legal Metrology
Legal Metrology applies to any application of metrology that is subjected to national laws or regulations.
There will be mandatory and legal bindings on the units and methods of measurements and measuring instruments.
The scope of legal metrology may vary considerably from one country to another. The main objective is to maintain uniformity of measurement in a particular country.
Legal metrology ensures the conservation of national standards and guarantees their accuracy in comparison with the international standards, thereby imparting proper accuracy to the secondary standards of the country.

22. Applications of Legal Metrology
Applications of legal metrology are industrial measurement, commercial transactions and public health and human safety aspects.

23. Role of Metrology in Manufacturing

24. Important Terms in Measurement

25. Precision
It is the degree of agreement of the repeated measurements of a quantity made by using the same method, under similar conditions.
Precision is the repeatability of the measuring process.
The ability of the measuring instrument to repeat the same results during the act of measurements for the same quantity is known as repeatability.
Repeatability is random in nature and, by itself, does not assure accuracy, though it is a desirable characteristic.

26. Accuracy
Accuracy is the degree of agreement of the measured dimension with its true magnitude
Accuracy can also be defined as the maximum amount by which the result differs from true value or as the nearness of the measured values to its true value often expressed as a percentage
True value may be defined as the mean of the infinite number of measured values when the average deviation due to the various contributing factors tends to zero

27. Accuracy and Precision

28. Inspection
Inspection is defined as a procedure in which a part or product characteristic, such as a dimension, is examined to determine whether it conforms to the design specification.
In inspection, the part either passes or fails. Thus, industrial inspection has become a very important aspect of quality control.

29. Resolution
It is the minimum value that can be measured when the instrument is gradually increased from non-zero value

30. Factors Effecting Part Accuracy
Workpiece
Machine & Control system design
Environmental Effects
Tool
Machine work zone Accuracy
Operating methods
Part Accuracy

31. Measuring Instrument Types
Angle measuring Instruments: e.g. Angle gauges; Divided scales; Sine bar with slip gauges; Autocollimator; and Tool Maker Microscope.
Length measuring Instruments: ex: Steel rule; Caliper; Micrometer; and comparators.
Instruments for surface finish: surface roughness measurements.
Instruments for deviations: Coordinate Measuring Machine (CMM).

32. Assignment one, 5%
What is Abbe principle from instrumentation concept?
What is role of Abbe principle in recent technology?
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