The act of measurement is essential on manufacturing sites. Measurements such as length and dimensions, temperature, pressure, weight, and electrical quantities not only determine product quality but are also directly connected to a company's credibility and safety.

What ensures that these measurement results can be considered accurate is instrument calibration.

What is Calibration? The Invisible Foundation Supporting Quality and Trust

Calibration is the process of verifying whether the values indicated by a measuring instrument are truly accurate and determining correction values when necessary. Over time, and under varying usage environments, measuring instruments can gradually deviate from their original accuracy. Calibration plays a critical role in detecting this drift and minimizing errors to ensure the reliability of measurement results.

Why Measurement Errors Occur

No matter how precise a measuring instrument is, errors and variations can still occur due to the following factors:

▲ Differences between theoretical measurement principles and real-world application
▲ Instrument-related errors (e.g., component wear or structural misalignment)
▲ Environmental influences on measurement (temperature, humidity, vibration, electromagnetic interference, etc.)
▲ Human errors in reading or handling the instrument

It is impossible to eliminate these factors entirely. That’s why it is essential to identify the degree of deviation and manage it appropriately.

The Importance of Repeated Measurements

Can a value obtained from a single measurement truly be considered accurate?

For example, when measuring a dimension of 100.0 mm:
Even if the first measurement reads “100.0 mm,” it could be a coincidence.
If the second measurement shows “99.8 mm,” it becomes unclear which value is truly accurate.

By repeating the measurement three, four, or five times, a pattern begins to emerge:
3rd measurement: “100.1 mm”
4th measurement: “100.0 mm”
5th measurement: “100.1 mm”

In this way, you can observe the trend that “this measuring instrument generally reads around 100.0 mm,” enabling you to assess the variation and stability of the measurement values.

In practice, taking into account work efficiency and actual site conditions, repeating measurements approximately 4 to 10 times is considered a practical guideline.

Purpose of Calibration

The main purposes of calibration are as follows:

A Calibration Certificate is issued as proof that calibration has been performed. This certificate includes key details such as the standard instruments used, the calibration methods, measurement results, and the evaluation of measurement uncertainty. It serves as an important record demonstrating that the calibration was carried out properly.

However, a certificate that merely states “calibrated” is not sufficient to fully demonstrate the reliability of the measurement values. This is why operation in accordance with ISO/IEC 17025 is essential.

Importance of ISO/IEC 17025

ISO/IEC 17025 is an international standard that certifies, through third-party assessment, that calibration and testing laboratories have reliable systems in place. These systems include ensuring measurement traceability, properly evaluating uncertainty, managing standard instruments, and maintaining the technical competence of technicians.

In other words, a calibration certificate issued under a management system based on ISO/IEC 17025 can reliably demonstrate that measurement traceability is ensured as its foundational basis.

In this way, calibration certificates are backed by the trusted framework of ISO/IEC 17025, which ensures that measurement values are both traceable and reliable.