**2.1. Unit of measurement**

measurement systems, verification, measurement accuracy, measurement precision, measurement error, data acquisition, evaluation of measurement results, the formation of statistical

The recognition that a measurement made by an industrial device is recognized worldwide and is the same as any other measurement made possible by achieving the highest precision basic measurement standard with a measurement reference chain. By fulfilling this, it is ensured that all the measurements carried out are accepted nationally and/or internationally. As a result, the calibration and verification processes have gained a great deal of importance. Calibration is a process of establishing a link between the values indicated by a measuring instrument or measuring system under certain conditions and the values obtained by a measuring instrument and corresponding values of corresponding measured values. With calibration, the measurement of a less precise measuring instrument or standard is carried out using an accepted standard of accuracy [2]. National metrology institutes are operating at the highest level, linked to the system by reference chain. These institutions are also linked to the Bureau International des Poids et Measure (BIPM) in central Paris in order to ensure that the measurements are internationally recognizable in a hierarchical structure. In the process of industrialization which started with serial production, it has become very important to establish a whole by combining the parts produced in different places, initiate specialization forms in the subsidiary industry

The reliability of measuring instruments has increased at the same rate as the widespread use of microelectronics. Nowadays, measurement techniques are required to meet demands for faster, more accurate, and more flexible measurements. The documentation of measurement results is equally important. The development of precise manufacturing technology brings the need for more precise measuring technology. The developments in technology, especially in the field of measuring technology, have been the main reason for the increasing demands on the accuracy of the measurement. As micro and nanotechnologies have been used, it has become inevitable to develop devices and instruments that enable the measurement opera-

New dimensions and research opportunities have been born in many scientific fields such as being in the electronics or molecular biology with nanotechnology. All of these disciplines are doing nanoscience studies on their own terms, and the opportunity to share all these different windows and share tools and techniques that develop independently is attractive to all sciences today. The placement of the atoms in the prescribed positions with the aid of nanotechnology is realized in this technology. Today the word "Nano" indicates a technique related to length measurements of very small objects in metrology, microtechnology, semiconductors, and nanotechnology fields. In nanometrology, the measurement size is typically specified as a nanometer. All applied methods are based on microscope technique with nano-position systems and position measurements at high accuracy. For instance, in mechanical engineering, nanotechnology and nanometrology are the necessary technologies to make a crystal perfect. The ability to precisely control the alignment of imprints and errors with respect to each other and the ability to integrate perfectly inorganic and organic nanostructures will lead to the emergence of a whole new generation of advanced composites. The improvements in technology intended to use the term *picotechnology* is a combination of picometer

evaluations, and quality determinations are the main subjects of metrology.

and production, and make the measurements internationally recognizable.

tions to be carried out at these accuracies.

4 Metrology

The most important condition of each measuring process and the manufacturing technique is the presence of units which are exactly defined according to the required quantities, and these units must be determined in accordance with internationally established rules. M*easurement* is a process that uses numbers to describe a physical quantity done to be able to compare them to each other. The results can be explained by a "*unit* of *measurement*,*"* which is a definite magnitude of a quantity. The *SI,* The International System of *Units,* is the modern form of the metric system, and the most widely used system of measurement is made up of 7 base *units* that define the 22 derived *units* with special names and symbols. Base units provide the reference used to define all the measurement units of the system, while the derived units are products of base units and are used as measures of derived quantities. Derived units are the units obtained by algebraic operations from basic and auxiliary units. Certain derived units have special names and symbols like acceleration, meter per second squared, m s−2.

#### **2.2. Uncertainty of measurement**

The uncertainty of a measurement is a predicament that characterizes the range of values, including the true value of the measure. *Measurement uncertainty* is an important topic for all measurement fields. All measurements have error. The error of a measurement is unknowable because one cannot know the error without knowing the true value of the quantity being measured. The *Evaluation of Measurement Data: Guide to the Expression of Uncertainty in Measurement* (GUM) provides general rules for evaluating and expressing uncertainty in measurement. The uncertainty of measurement generally includes many components. Some of these components can be estimated on the basis of the statistical distribution of series measurement results and can be characterized by empirical standard deviations. The estimates of the other components are based solely on the main information or experiences. The uncertainty of measurements should be evaluated and reported according to the related international standards.

## **2.3. Calibration**

The purpose of calibration is to determine and document how much of the equipment is in error with the actual value. The correct value is obtained by considering the amount of error in the result. Calibration is the process of determining the relationship between the value read in a gauge and the gauge size. Calibration and control of measuring, inspection, and control equipments ensure the appropriateness of measurements made during manufacturing. The continuity of this safety is ensured by the regular and identifiable calibration of the equipment in question. Calibration is performed by comparison with a measurement of normality known to the measurement magnitude. To sum up, calibration is explained in the related standard: under specified conditions, the series of operations in which the relationship between the values indicated by a measuring instrument or device and the values indicated by a material measurement or reference material is established [3]. In order to supply traceability in measurements, calibration hierarchy in **Figure 1** should be followed up carefully.

cal tools and methods to acquisite and to analyze data in order to monitor process capabilities, it is widely used in data evaluation. Quality control charts and the other statistical tools are used to analyze processes enabling appropriate actions to achieve improved or stabilized processes. They help to ensure that the process operates efficiently and allow organizations to understand variation in their processes, differentiating common causes from special or assignable causes of variation.

Introductory Chapter: Metrology

7

http://dx.doi.org/10.5772/intechopen.75541

Metrology is a crucial science including its standards, systems of units, instruments, calibration procedures, uncertainties, inspection, and quality control topics in many industries such as automotive, aerospace, mechanical engineering, surface engineering, etc. and in many sciences like natural and applied sciences in different sizes like micro and nanometrology serving for sustainable improvements. Like being in today, there will always be valuable researches in the field of metrology, with the help of technological developments to support the scientific researches in the future. Care taken in the reliability of measurements and their traceability will always be crucial. Metrology is such useful for humanity if it is conducted

I would like to thank the authors for their contributions and the publisher that provided this

Mechanical Engineering Department, Yildiz Technical University, İstanbul, Turkey

[1] International Vocabulary of Metrology: Basic and General Concepts and Associated

[2] Uncertainty of measurement: Part 3: Guide to the expression of uncertainty in measure-

[3] Measurement management systems: Requirements for measurement processes and

**4. Conclusions**

**Acknowledgements**

opportunity.

**Author details**

Anil Akdogan

**References**

according to its rules and international standards.

Address all correspondence to: nomak@yildiz.edu.tr

Terms. 3rd ed. VIM; 2012. JCGM 200:2012

ment. GUM; 1995. ISO/IEC Guide 98-3:2008

measuring equipment. 2003. ISO 10012:2003
