Metrology and Inspection Viva Questions and Answers

Metrology and Inspection Viva Questions and Answers

Q: What is metrology?


Metrology is the scientific study of measurement, including the design, development, and calibration of measurement equipment and techniques used in industry, science, and other fields.

Q: What are the basic principles of metrology?


The basic principles of metrology are accuracy, precision, traceability, and repeatability. Accurate measurements are those that are close to the true value, while precise measurements are those that have low variability or uncertainty. Traceability refers to the ability to trace a measurement result back to a known standard, while repeatability refers to the consistency of measurement results over multiple trials.


Q: What is the difference between metrology and inspection?


Metrology is concerned with the measurement and calibration of instruments and equipment used in various industries, while inspection involves the examination of products, components, or materials to ensure that they meet certain quality standards or specifications.

Q: What are the different types of inspection?


There are several types of inspection, including visual inspection, dimensional inspection, non-destructive testing, and functional testing.

Q: What is dimensional inspection?


Dimensional inspection is a process that involves the measurement of physical dimensions of a part or component to ensure that it meets certain design specifications or quality standards.


Q: What is non-destructive testing (NDT)?


Non-destructive testing (NDT) is a technique used to inspect materials, components, or structures without damaging or altering them. Examples of NDT techniques include radiography, ultrasonic testing, and magnetic particle inspection.

Q: What is a calibration certificate?


A calibration certificate is a document that provides details of the calibration performed on a measuring instrument or equipment. The certificate typically includes information such as the instrument’s make and model, the calibration procedure used, the calibration standards applied, and the results of the calibration.

Q: What is the purpose of an inspection report?


The purpose of an inspection report is to provide a detailed account of the inspection results, including any defects or non-conformities found, as well as any corrective actions taken or recommended.


Q: What is the role of metrology in quality control?


Metrology plays a crucial role in quality control by ensuring that measuring instruments and equipment used in production processes are accurate and reliable, and that products or components meet design specifications or quality standards.

Q: How do you ensure that measurement instruments are calibrated properly?

Measurement instruments can be calibrated properly by following a set of standard procedures, including selecting appropriate calibration standards, ensuring proper environmental conditions, conducting multiple measurements, and documenting the calibration results in a calibration certificate.


Q: Why is metrology important?

A: Metrology is important because it provides a foundation for accurate and reliable measurements, which are essential in a wide range of fields, including science, engineering, manufacturing, and commerce.

Q: What are the different types of measurement systems?

A: The different types of measurement systems include the metric system (also known as the International System of Units or SI), the imperial system, and the US customary system.

Q: What is surface metrology?
A: Surface metrology is the study of the measurement of surface topography, including roughness, waviness, and form.

Q: What is calibration?

A: Calibration is the process of comparing a measuring instrument or system to a standard reference instrument or system to ensure accuracy.

Q: What is traceability?

A: Traceability is the ability to trace the measurement results of a measurement system or instrument back to a national or international standard reference.

Q: What is a measurement uncertainty?

A: Measurement uncertainty is the doubt or doubt range associated with a measurement result, arising from the limitations of the measuring instrument, the measurement process, and the environment in which the measurement was made.

Q: What is an inspection?

A: Inspection is the process of examining a product or service against a set of predetermined standards or specifications to determine its acceptability.

Q: What is statistical process control?

A: Statistical process control is a method of monitoring and controlling a process by analyzing and interpreting statistical data to identify and reduce variations in the process.

Q: What is Six Sigma?

A: Six Sigma is a quality management approach that seeks to minimize defects and variations in a process by focusing on continuous improvement and rigorous statistical analysis.

Q: What is a quality control plan?

A: A quality control plan is a document that outlines the quality requirements and procedures for a product or service, including the inspection and testing procedures to ensure that the requirements are met.


Q: What is the purpose of measurement standards?

A: The purpose of measurement standards is to ensure that all measurements made in a particular field are consistent and comparable, regardless of the instrument or laboratory used.

Q: What is the difference between accuracy and precision in measurement?

A: Accuracy refers to how close a measured value is to the true value, while precision refers to how reproducible a measurement is.

Q: What is a measurement system analysis (MSA)?

A: A measurement system analysis (MSA) is a statistical method used to evaluate the accuracy, precision, and stability of a measurement system.

Q: What is a gauge R&R study?

A: A gauge R&R study is a type of MSA used to assess the repeatability and reproducibility of a measurement system, typically using a gauge or measuring instrument.

Q: What is a measurement standard traceability chain?

A: A measurement standard traceability chain is a series of comparisons that trace a measurement result back to a national or international standard reference, providing assurance of the measurement’s accuracy and reliability.

Q: What is the purpose of a calibration interval?

A: The purpose of a calibration interval is to ensure that a measuring instrument or system is calibrated at regular intervals to maintain its accuracy and reliability over time.

Q: What is a measurement uncertainty budget?

A: A measurement uncertainty budget is a document that identifies and quantifies the sources of uncertainty associated with a measurement result, including the instrument, the measurement process, and the environment.

Q: What is a gage block?

A: A gage block is a precision measuring tool used to calibrate and verify the accuracy of measuring instruments, such as micrometers and dial indicators.

Q: What is a micrometer?

A: A micrometer is a measuring instrument used to measure small distances with high precision, typically up to 0.001 mm.

Q: What is a surface roughness symbol?

A: A surface roughness symbol is a set of numbers and symbols used to indicate the roughness, waviness, and lay of a surface, typically in a technical drawing or specification.

Q: What is a visual inspection?

A: A visual inspection is the process of examining a product or component with the naked eye or with the aid of magnification or illumination, to detect visible defects or anomalies.

Q: What is a borescope?

A: A borescope is an optical instrument used to inspect the interior of a narrow or inaccessible space.

Q: What is a digital image correlation (DIC)?

A: Digital image correlation (DIC) is a non-contact method of measuring deformation and strain in materials or components, using images captured by a camera and analyzed using software.

Q: What is a load cell?

A: A load cell is a type of sensor used to measure force or weight, typically by measuring changes in electrical resistance or capacitance.

Q: What is a durometer?

A: A durometer is a measuring instrument used to measure the hardness or stiffness of materials, typically elastomers or plastics.

Q: What is a spectrophotometer?

A: A spectrophotometer is a measuring instrument used to measure the absorption or transmission of light by a material, typically for analysis of chemical or biological samples.

Q: What is a refractometer?

A: A refractometer is a measuring instrument used to measure the refractive index of a material, typically a liquid or a solution, and used to determine the concentration of dissolved solids.

Q: What is a colorimeter?

A: A colorimeter is a measuring instrument used to measure the color of a material or solution, typically by comparing it to a standard color reference.

Q: What is a profilometer?

A: A profilometer is a measuring instrument used to measure the surface roughness and texture of a material or component.

Q: What is a laser tracker?

A: A laser tracker is a type of coordinate measuring machine (CMM) that uses laser technology to precisely measure the position and orientation of a target or component.

Q: What is a coordinate measuring machine (CMM)?

A: A coordinate measuring machine (CMM) is a computer-controlled device used for precise measurement of three-dimensional objects.

Q: What is a contour measuring machine?

A: A contour measuring machine is a type of coordinate measuring machine (CMM) used to measure the shape and profile of a three-dimensional object, typically by scanning the object with a probe or laser.

Q: What is a hardness tester?

A: A hardness tester is a measuring instrument used to measure the hardness or stiffness of a material, typically by indenting or scratching the surface of the material.

Q: What is a destructive testing method?

A: A destructive testing method is a technique used to test the properties or condition of a material or component by intentionally damaging or destroying it, typically using methods such as tensile testing, compression testing, or fracture testing.

Q: What is the difference between resolution and accuracy in metrology?

A: Resolution refers to the smallest measurable increment of a measurement system, while accuracy refers to how close the measured value is to the true value.

Q: What is the difference between repeatability and reproducibility in metrology?

A: Repeatability refers to the variation in measurements taken by the same person or instrument under the same conditions, while reproducibility refers to the variation in measurements taken by different people or instruments.

Q: What is the difference between precision and accuracy in metrology?

A: Precision refers to the degree of variation in a series of measurements, while accuracy refers to how close the measured value is to the true value.

Q: What is the difference between a calibration standard and a reference standard?

A: A calibration standard is a device or material used to calibrate a measuring instrument, while a reference standard is a device or material used to establish a known value or quality for comparison purposes.

Q: What is a gauge block?

A: A gauge block is a precision measuring tool used to calibrate or check the accuracy of other measuring instruments, typically by stacking multiple blocks together to create a precise measurement.

Q: What is a micrometer?

A: A micrometer is a precision measuring tool used to measure small distances or thicknesses, typically with a spindle and anvil that can be adjusted to capture and measure the object being measured.

Q: What is a vernier caliper?

A: A vernier caliper is a precision measuring tool used to measure distances or dimensions, typically with a sliding scale and a vernier scale that provides additional precision.

Q: What is a dial indicator?

A: A dial indicator is a precision measuring tool used to measure small distances or variations in dimensions, typically with a dial or digital display that shows the measurement.

Q: What is a height gauge?

A: A height gauge is a precision measuring tool used to measure the height or distance between two surfaces, typically with a vertical scale and a measuring jaw or probe.

Q: What is a bore gauge?

A: A bore gauge is a precision measuring tool used to measure the diameter or size of a hole or bore, typically with a set of expandable or interchangeable heads.

Q: What is a go/no-go gauge?

A: A go/no-go gauge is a precision measuring tool used to quickly determine if a part or component meets certain dimensional or tolerance requirements, typically with a set of gauging pins or plugs that are either the correct size or not.

Q: What is a surface plate?

A: A surface plate is a precision flat surface used as a reference or workpiece for dimensional measurement or inspection, typically made of granite or other high-quality material.

Q: What is a comparator?

A: A comparator is a precision measuring tool used to compare the dimensions or characteristics of a part or component to a known standard, typically with a set of gauging pins or a magnifying lens.

Q: What is a shadowgraph?

A: A shadowgraph is a type of non-contact inspection system used to measure the contours or surface features of a part or component by projecting a shadow onto a screen or camera.

Q: What is a coordinate measuring system?

A: A coordinate measuring system is a type of measuring system that uses a set of coordinates or reference points to precisely measure the position, shape, and size of a part or component, typically using a computer-controlled measuring machine.

Q: What is a laser interferometer?

A: A laser interferometer is a high-precision measuring tool that uses laser light to measure distances or small changes in position or orientation, typically with a beam splitter and a detector.

Q: What is a CMM?

A: CMM stands for Coordinate Measuring Machine. It is a computer-controlled measuring system used to measure the position, shape, and size of a part or component with high precision.

Q: What is a profile projector?

A: A profile projector is a type of optical inspection system used to measure the dimensions or contours of a part or component by projecting its profile onto a screen and comparing it to a template or standard.

Q: What is an optical comparator?

A: An optical comparator is a type of non-contact inspection system used to measure the dimensions or characteristics of a part or component by projecting an image onto a screen and comparing it to a template or standard.

Q: What is a hardness tester?

A: A hardness tester is a measuring instrument used to determine the hardness of a material by measuring its resistance to indentation or penetration, typically using a diamond or tungsten carbide point.

Q: What is a surface roughness tester?

A: A surface roughness tester is a measuring instrument used to measure the roughness or texture of a surface, typically using a stylus or optical probe.

Q: What is a roundness tester?

A: A roundness tester is a measuring instrument used to measure the roundness or circularity of a part or component, typically using a rotary table and a precision probe.

Q: What is a form tester?

A: A form tester is a measuring instrument used to measure the form or shape of a part or component, typically using a precision probe and a computer-controlled measuring system.

Q: What is a video measurement system?

A: A video measurement system is a type of non-contact inspection system used to measure the dimensions or characteristics of a part or component by analyzing images captured by a camera and software.

Q: What is a microstructure analyzer?

A: A microstructure analyzer is a measuring instrument used to analyze the microstructure or internal structure of a material, typically using microscopy and image analysis software.

Q: What is a torque tester?

A: A torque tester is a measuring instrument used to measure the torque or rotational force of a rotating shaft or other mechanical component, typically using a strain gauge or other sensor.

Q: What is a pressure gauge?

A: A pressure gauge is a measuring instrument used to measure the pressure or force of a fluid or gas, typically using a Bourdon tube or other pressure-sensitive element.

Q: What is a flow meter?

A: A flow meter is a measuring instrument used to measure the flow rate or volume of a fluid or gas, typically using a sensor or other measuring element.

Q: What is a thermometer?

A: A thermometer is a measuring instrument used to measure the temperature of a material or environment, typically using a sensor or other measuring element.

Q: What is a pyrometer?

A: A pyrometer is a measuring instrument used to measure the temperature of a material or environment at high temperatures, typically using infrared radiation or other non-contact methods.

Q: What is a spectrometer?

A: A spectrometer is a measuring instrument used to measure the spectral composition of light or other electromagnetic radiation, typically using a diffraction grating or other optical element.

Q: What is a mass spectrometer?

A: A mass spectrometer is a measuring instrument used to measure the mass and composition of particles or molecules in a sample, typically using ionization and mass-to-charge ratio analysis.

Q: What is a gas chromatograph?

A: A gas chromatograph is a measuring instrument used to separate and analyze the components of a gas or vapor mixture, typically using a column and detector.

Q: What is a spectrophotometer?

A: A spectrophotometer is a measuring instrument used to measure the absorption, transmission, or reflection of light by a sample, typically using a monochromator and detector.

Q: What is a colorimeter?

A: A colorimeter is a measuring instrument used to measure the color or chromaticity of a sample, typically using filters and detectors.

Q: What is a densitometer?

A: A densitometer is a measuring instrument used to measure the density or optical density of a sample, typically using a light source and detector.

Q: What is a profilometer?

A: A profilometer is a measuring instrument used to measure the surface profile or roughness of a sample, typically using a stylus or optical probe.

Q: What is a coordinate measuring system?

A: A coordinate measuring system is a type of inspection system used to measure the position, size, and shape of a part or component in three-dimensional space, typically using a CMM or other coordinate measuring device.

Q: What is a gage block?

A: A gage block is a precision measuring tool used to calibrate other measuring instruments and to verify the accuracy of their measurements.

Q: What is a laser interferometer?

A: A laser interferometer is a measuring instrument used to measure the displacement, position, or motion of a sample or component with high precision, typically using laser light and interference patterns.

Q: What is a strain gauge?

A: A strain gauge is a measuring instrument used to measure the strain or deformation of a material or component, typically using a resistive element.

Q: What is a piezoelectric sensor?

A: A piezoelectric sensor is a measuring instrument used to measure the force, pressure, or acceleration of a sample or component, typically using a piezoelectric crystal.

Q: What is a digital microscope?

A: A digital microscope is a type of microscope that captures digital images of a sample or component for inspection and analysis.

Q: What is a scanning electron microscope?

A: A scanning electron microscope is a type of microscope that uses an electron beam to create high-resolution images of the surface of a sample or component.

Q: What is a transmission electron microscope?

A: A transmission electron microscope is a type of microscope that uses an electron beam to create high-resolution images of the internal structure of a sample or component.

Q: What is a confocal microscope?

A: A confocal microscope is a type of microscope that uses a laser beam and a pinhole aperture to create high-resolution images of the surface or internal structure of a sample or component.

Q: What is a micro CT scanner?

A: A micro CT scanner is a type of scanner that uses X-rays to create high-resolution 3D images of the internal structure of a sample or component.

Q: What is a surface plasmon resonance sensor?

A: A surface plasmon resonance sensor is a measuring instrument used to detect changes in the refractive index or mass of a sample or component, typically using an optical sensing element.

Q: What is a calorimeter?

A: A calorimeter is a measuring instrument used to measure the heat of a sample or component, typically using a thermocouple or other temperature-sensitive element.

Q: What is a viscometer?

A: A viscometer is a measuring instrument used to measure the viscosity or fluidity of a sample or component, typically using a rotating or falling ball or spindle.

Q: What is a rheometer?

A: A rheometer is a measuring instrument used to measure the rheological properties of a sample or component, such as its viscosity, elasticity, and yield stress

Q: What is a surface finish gauge?

A: A surface finish gauge is a measuring instrument used to measure the surface roughness or finish of a sample or component, typically using a stylus or optical probe.

Q: What is a hardness tester?

A: A hardness tester is a measuring instrument used to measure the hardness or resistance to indentation of a material or component, typically using a standardized indenter and load.

Q: What is a tensile testing machine?

A: A tensile testing machine is a measuring instrument used to measure the mechanical properties of a material or component, such as its strength, stiffness, and ductility, by applying a tensile force.

Q: What is a compression testing machine?

A: A compression testing machine is a measuring instrument used to measure the compressive strength or resistance of a material or component, typically by applying a compressive force.

Q: What is a torque wrench?

A: A torque wrench is a measuring instrument used to apply a specific torque or rotational force to a bolt or other fastener, typically using a calibrated scale or indicator.

Q: What is a micrometer?

A: A micrometer is a measuring instrument used to measure the thickness, diameter, or length of a small component or feature with high precision, typically using a screw mechanism and scale.

Q: What is a vernier caliper?

A: A vernier caliper is a measuring instrument used to measure the length, width, or thickness of a component or feature with high precision, typically using a sliding scale and vernier mechanism.

Q: What is a height gauge?

A: A height gauge is a measuring instrument used to measure the height or vertical distance between two surfaces or points on a component or feature, typically using a calibrated scale or indicator.

Q: What is a thread gauge?

A: A thread gauge is a measuring instrument used to measure the pitch, diameter, or angle of a screw or threaded component, typically using a series of calibrated threads.

Q: What is a roundness tester?

A: A roundness tester is a measuring instrument used to measure the roundness or circularity of a component or feature, typically using a rotating spindle and sensor.

Q: What is a surface plate?

A: A surface plate is a precision flat surface used as a reference standard for the measurement of other components or features, typically made of granite or other stable material.

Q: What is a dial indicator?

A: A dial indicator is a measuring instrument used to measure the position, displacement, or deflection of a component or feature, typically using a spring-loaded plunger and dial display.

Q: What is a laser tracker?

A: A laser tracker is a measuring instrument used to measure the position and orientation of a large or complex component or structure, typically using a laser beam and reflective targets.

Q: What is a vision system?

A: A vision system is a type of inspection system used to inspect and measure the features, dimensions, and defects of a component or product using digital cameras and image processing algorithms.

Q: What is a coordinate measuring machine (CMM)?

A: A coordinate measuring machine (CMM) is a measuring instrument used to measure the position, size, and shape of a part or component in three-dimensional space, typically using a touch probe or other sensing element.

Q: What is an optical comparator?

A: An optical comparator is a measuring instrument used to measure the dimensions, angles, and contours of a component or feature by comparing it to a magnified and projected image of a standard or template.

Q: What is a non-contact measurement system?

A: A non-contact measurement system is a type of inspection system that measures the features, dimensions, and defects

Q: What is a surface roughness scale?

A: A surface roughness scale is a set of standardized parameters and values used to describe the surface finish or texture of a component or feature, typically based on measurements taken using a surface finish gauge or profilometer.

Q: What is a tolerance?

A: A tolerance is a specified allowable deviation from a nominal or target value or dimension for a component or feature, typically expressed as a range or limit.

Q: What is a repeatability?

A: Repeatability is the ability of a measuring instrument or system to produce consistent results when measuring the same component or feature multiple times under the same conditions.

Q: What is a reproducibility?

A: Reproducibility is the ability of a measuring instrument or system to produce consistent results when measuring the same component or feature by different operators or under different conditions.

Q: What is the difference between accuracy and precision?

A: Accuracy refers to how close a measurement is to its true value, while precision refers to how consistent or repeatable a measurement is.

Q: What is a gage block?

A: A gage block is a precision block used as a reference standard for the measurement of other components or features, typically made of hardened steel or other stable material.

Q: What is a master gauge?

A: A master gauge is a measuring instrument used to calibrate or verify the accuracy of other measuring instruments or systems, typically made to a high degree of precision.

Q: What is an alignment tool?

A: An alignment tool is a measuring instrument or system used to align or position components or features in a precise and accurate manner, typically using optical or mechanical means.

Q: What is a surface roughness symbol?

A: A surface roughness symbol is a standardized symbol or code used to indicate the surface finish or texture of a component or feature, typically based on measurements taken using a surface finish gauge or profilometer.

Q: What is a quality control plan?

A: A quality control plan is a document or system used to ensure that a product or component meets specified quality requirements, typically including procedures for inspection, testing, and corrective action.

Q: What is a failure mode and effects analysis (FMEA)?

A: A failure mode and effects analysis (FMEA) is a systematic approach to identifying and addressing potential failures or defects in a product or component, typically by analyzing the possible causes, effects, and severity of each failure mode.

Q: What is a control chart?

A: A control chart is a graphical tool used to monitor and control the quality of a process or product over time, typically by plotting sample data and comparing it to control limits or specifications.

Q: What is a capability index?

A: A capability index is a statistical measure of the ability of a process or product to meet specified quality requirements, typically based on the variability of the process or product relative to its specifications.

Q: What is a gauge R&R study?

A: A gauge R&R study is a statistical method used to assess the repeatability and reproducibility of a measuring instrument or system, typically by analyzing the variation in measurements taken by different operators using the same instrument on the same component or feature.

Metrology and Inspection Viva Questions and Answers



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