Measurement
The importance of measuring instruments in ensuring the quality of machined products is undeniable. Efficient and accurate measurement not only helps ensure product quality but also saves time and resources in production processes. The accuracy and reliability of measuring instruments used for dimensional inspection and quality assurance of machined parts are crucial.
Measuring machined products requires precision and reliable measuring instruments. Calipers, micrometers, dial indicators, and surface-roughness measuring devices are all cornerstones of high-quality, accurate measurement in the cutting-tool manufacturing industry. These measuring instruments support important quality assurance decisions that directly affect the final quality of the products.
Calipers are among the most common and versatile measuring instruments, used to measure external and internal dimensions as well as depths. The use of this “machinist’s all-purpose measuring tool” is governed by the general tolerances specified in the SFS-EN 22768-1 standard, which defines the permitted dimensional deviations. The digital age has also introduced modern technology to calipers, such as digital displays and wireless data transfer, improving the reliability of measurement results and making them easier to process.
Micrometers provide even more accurate measurement results when tolerances in accordance with the ISO tolerance system and the SFS-EN ISO 286 standard are required. Micrometers are specialized measuring tools for taking dimensions from various features, such as external and internal surfaces, as well as specialized features like the flank diameter of threads or the tooth spaces of gears. Modern micrometers often include advanced functions that combine high accuracy with ease of use.
A surface-roughness measuring device is likewise an essential tool for determining the surface quality of a machined part. Surface roughness affects not only the aesthetic properties of a part but also, for example, its sliding characteristics and fatigue resistance. For this reason, measuring surface roughness is an important part of the quality assurance process. It helps ensure that the machined part meets its specified requirements and prevents costly over-quality in production.
To ensure reliable measurements, it is absolutely essential that the measuring instruments in use are properly maintained and calibrated. Measurement uncertainty—the uncertainty regarding how close a measurement result is to the true value—is a factor that affects all measurements. Taking measurement uncertainty into account when reporting measurement results is therefore an essential part of both quality assurance and ensuring the reliability of measurement results.
The selection, maintenance, and calibration of measuring instruments are critical processes that require care and expertise. By choosing high-quality measuring instruments and keeping them well maintained and regularly calibrated, the quality and reliability of measured products can be significantly improved. In addition, identifying measurement uncertainty and taking it into account when reporting measurement results is essential for improving the reliability of measurement data.
Every measuring instrument, regardless of its size or intended purpose, wears over time. This wear may be so slight that it is not visible to the naked eye, but even small deviations can lead to significant errors in measurement results. For this reason, regular calibration of measuring instruments is essential. Calibration is used to check the condition and measuring capability of a device and to compare the results obtained with approved standards. If the results deviate from the accepted values, the measuring device must be recalibrated or removed from service.
As a general practice, a measuring instrument should be calibrated when the final month of use indicated on its calibration label is reached, or whenever there is reason to question the instrument’s condition. It is important to remember that a measuring instrument must not be used if it does not have a valid calibration label or if its calibration period has expired.
ISO 9001 is a quality management system standard published by the International Organization for Standardization (ISO). The standard requires all measuring instruments used for monitoring and measurement to be either calibrated or verified as meeting the specified requirements. The calibration process must be based on comparisons with measurement standards that are traceable to international or national standards. Managing measuring instruments in accordance with ISO 9001 demonstrates an organization’s commitment to accuracy and quality, thereby strengthening the confidence of customers and stakeholders.
Calibration of measuring instruments is generally indicated with a color-coded label. The color of the label indicates the year of the next calibration, while the number on the label indicates the calibration month. For example, a red color-coded label with the number zero means that the measuring instrument must not be used until it has been recalibrated. These labels provide an easy and quick way to ensure that the measuring instruments in use are up to date and reliable.
Proper and regular calibration is critically important for quality assurance. It not only reduces the risk of measurement errors but also lowers manufacturing costs by improving process efficiency. In addition, proper maintenance and storage of measuring instruments help ensure their long service life and accuracy. Operating in accordance with ISO 9001 demonstrates a commitment to high-quality management, which builds trust among both customers and stakeholders. When all these factors are taken into account, it is clear that calibrating measuring instruments is an essential part of the operations of any organization committed to quality.
