Metrology

Geometry of Form or Shape (Metrology)

1.21. The measurement of geometrical values in modern engineering has become a factor of vital importance in the process of production due to higher and higher requirements for the accuracy of machined surfaces. Any machine is assembly of parts arranged in a definite relationship of each other. The surfaces of the various parts joining each […]

Quality Improvement Programmes (Metrology)

1.23. Implementation of quality improvement programmes results into: — dramatic reduction of defects — improvement in overall product reliability — dramatic decrease in the cost of quality — increased customer satisfaction — increased overall market share. The philosophy behind quality improvement program is depicted by following: — Quality is free since it pays for itself […]

Optical Principles (Metrology)

1.22. More and more precision measuring instruments employ optical principles and as such brief study of optical principles is considered essential. The purpose of the optical system is to enable an image of the object being examined to be formed, generally to permit particular measurements to be made. The classes of measurements to which optics […]

Managing Measuring Equipment (Metrology)

1.24. Measurement is the process of assigning a value to a given physical quantity. Quality is the capability of a product (or a service) to meet stated and implied needs. Measurements have significant role in product quality through the testing of products against a relevant specification, after completion of manufacture. In many cases tests are […]

Quality, Standardisation, Testing and Metrology (QSTM) (Metrology)

1.26. Global trade depends on quality and metrology to establish confidence between customers and supplier. Global trade is open to all and in order to take part effectively in today’s global economy, QSTM activities are essential to improve productivity and ensure social and economic development. The basic concerns for QSTM programme are to ensure competitiveness, […]

Measurements and Traceability (Metrology)

1.25. Measurement is necessarily a science of comparison. For a measurement result to be meaningful, it has to be traceable to national standards. The SI system of units consisting of 28 units (7 base, 2 supplementary and 19 derived units) are the basis of all modern measurements. The SI is a set of definitions. National […]

Linear Measurements (Metrology)

2.1. Introduction The aim of the inspection of a component is to see whether it lies within the prescribed limits or not and as to whether it meets the workmanship demanded by service specifications. The critical examination of any component can be made by means of measuring instruments capable of dimensional control. Measuring instruments are […]

Line Graduated Measuring Instruments (Metrology)

2.2. Line graduated measuring instruments incorporate graduation spacings representing known distances. These are used for direct measurements of specific distances within their capacity range. The sensitivity of the measurement is dependent primarily on the instrument’s basic design (the least distance between the individual graduations). The measuring accuracy is affected by the original accuracy of the […]

Steel Rule (Metrology)

2.3. It is also known as scale. It is a line measuring device. It is the simplest and most common measuring instrument used in inspection. It works on the basic measuring technique of comparing an unknown length to the one previously calibrated. It consists of a strip of hardened steel having line graduations etched or […]

Calipers (Metrology)

2.4. For the parts which can’t be measured directly with the scale, assistance of calipers can be taken. Calipers thus act as accessories to scales. The caliper consists of two legs hinged at top, and the ends of legs span the part to be inspected. This span is maintained and transferred to the scale. It […]