A Short Introduction to Metrology

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Measurements are something that we use every single day in a variety of industries, and yet we do not often think about them as something that requires scientific methodology.Taken from the Greek words “metron” (measure) and “logos” (reason), metrology is the term used for thestudy of measurement. Metrology tackles both experimental and theoretical sides of the field, and is a basic requirement for anybody interested in going into a career in science and technology.

Basic Ideas in Metrology

A basic tenet of this field is the idea that there is no single measurement that is truly exact or certain. In fact, all that any scientist can do is to create estimations. While measuring can give us a much more accurate estimate, it is still, in the end, just an estimate, and thus it may still be an uncertain result. Due to this, scientists must incorporate the concept of confidence. This means assigning some limitations to this uncertainty. Assigning a higher range of uncertainty usually means there is higher confidence in encompassing the true values.

Standards of Measurement

It is of utmost importance for different laboratories and manufacturers to use the same standards of measurement throughout the world. This ensures that any parts that are created in one country are compatible with any parts from another country. Most measuring instruments thus undergo calibration, wherein one measurement is compared with another. For example, rulers may be compared against a reference ruler in order to determine whether the markings are positioned correctly or not.

Instruments Used in Metrology

There are many different kinds of instruments used in metrology, including dial indicators, calipers, and force gauges, to name a few. As they deal with the science of measurement, they are built so that they can detect even the smallest of units for ultra-precise results.Many optical metrology systems, in particular, utilize precision linear stages, an important component that allows for high precision optical imaging. Advances in technology have also allowed for 3D metrology using much more compact and stable machines.

Measurement System Analysis

MSA aims to quantify just how accurate certain measurements are by summing up trueness and precision. Trueness or bias refers to how close the mean of a set of measurements is to the true value. Precision refers to how repeated measurements will show the same results, and is based on:

  • Repeatability: repeating a measurement with the exact same conditions in a short period of time and observing whether the results are consistent or not
  • Reproducibility: repeating a measurement in different sets of conditions over a long period of time, and checking how the results of each measurement may vary

Measurements are something so ingrained in our everyday lives that we take it for granted. However, as this article shows, much goes into the study of measuring our observable world, all with the goal of progressing science and technology. The next time you need to measure something for your business, think of the great minds and high quality equipment behind it all.