MESACON’s measuring systems open up a wide range of applications in the field of non-contact thickness measurement, and can provide the competitive advantage for manufacturing processes. In times of Industry 4.0, the requirements for the digitalisation of production data are increasing. Higher data densities lead to ever better process understanding, more efficient production and detailed documented quality.

MESACON’s more than 60 years of experience in the field of non-contact thickness measurement has also been incorporated into the product line of laser-optical measuring systems. The primary approach is always the simplicity of the system in the aspects of integration, handling and operation. The focus is always on system precision and performance to reliably achieve the measuring capability important in quality management, even with demanding measurement specifications.

Laser triple-spot system for automotive industry

Laser triple-spot system for automotive industry

» Low maintenance and compact design

The F5500 measuring systems are extremely low-maintenance devices, and can be used as a plug & play solution for non-contact and alloy-independent thickness measurement of flat products, such as metal strips or sheets, foils or plastic and textile webs. The compact design enables straightforward line integration even in confined installation spaces.

Based on the principle of laser distance or difference measurement, the laser triangulation method or the confocal chromatic measurement method is used, depending on the application. A pair of sensors integrated in a mechanical system are placed opposite each other on either side of the material, and measures without contact from above and below against the material surface.

Detailed view of confocal chromatic laser gauge

Detailed view of confocal chromatic laser gauge

For special applications, where laser distance measurement is not suitable, the thickness measurement is carried out against a deflection roller with an optical high-speed LED micrometer.

» Accurate measurement in dynamic processes

In all laser-optical measuring systems, the measuring principle of differential measurement is based on constant distances between the individual sensors. Thermal and dynamic deformations of the mechanics, such as with temperature changes or high scanning speeds, have a direct influence on the sensor geometry, as well as vibrations and oscillations. This influence is often in the range of a few micrometres, but without compensation, it can influence the system performance by a multiple of the single sensor accuracy.

Detailed view of LED micrometer system

Detailed view of LED micrometer system

» Thickness of a human hair – or “what is a micrometre?”

To get a feeling for these deviations and influences, here is a practical example. If you take the average human hair, it is about 0.05 to 0.08 mm thick, i.e. 50 to 80 µm. In the case of fine hair, one speaks of about 20 to 40 µm.
The accuracy requirements for thickness measurement are often in the thousandths range, i.e. 10 µm or less. The challenge is not the repeatability or the sampling rate, but rather the consistency of the sensor geometry with regards to the material to be measured.

For example, temperature changes in the measuring position can cause thermal deformations in the mechanics due to material-dependent expansion coefficients. These quickly lead to a few micrometres of deviation in the sensor geometry and thus to an additional measurement error. Most of the system-inherent influencing variables cannot be seen or observed, but they all have a direct effect on the measurement result or the system performance.

In general, deviations or changes in the sensor geometry lead to an additional measurement error. These influencing variables can be differentiated according to system-related and application-related influences.

Influencing variables inherent into measuring system:

» Dynamic deformation due to traversing of the mechanics
» Thermal deformation due to temperature change
» Inhomogeneity in the properties of the reference sample
(surface roughness, thickness, …)

Application-specific influencing variables:

» Strip position and strip guidance
» Roughness and reflective properties of the surface
» Coatings and fluids

» Distinction between sensor accuracy and system performance

Terms such as measurement and sensor accuracy, system performance and repeatability are often mixed together – used promotionally effective for the “ideal case” – without reference to the actual and real system accuracy for the customer’s measurement task. MESACON always state the system performance as the result of all individual accuracies and influencing factors of the respective application.

Thus, many factors flow into the consideration of the measurement system accuracy. In addition to the linearity of the individual sensors, which define the sensor accuracy for the respective measuring range, the repeatability and the additional thermal error of the sensors, all of the above-mentioned system-related influences must also be evaluated in the system performance.

The additional “mechanical influence” depends upon, amongst other things, the length of the mechanics and the adjustment interval of the measuring system.

» Experience and solution concepts

In general, MESACON can minimise and avoid additional measuring errors based on many years of experience in the field of non-contact thickness measurement, and with the special mechanical solution concepts for dynamic and thermal deformations. Thus, compared to other market competitors, even large material widths can be measured with high scanning speeds in traversing applications. In addition to multi-track measurements, individual scan patterns can also be realised across the material width or in defined sectors. Different standard interfaces allow flexible integration into the system environment adapted to customer requirements.

The powerful and globally proven MESACON software offers numerous options for data filtering and evaluation of the measurement data. For example, the selection of signal peaks or signal averaging can be freely configured on the system side to optimise the measurement task.

The intuitive operating concept offers user-specific settings for the respective measuring task, such as the measuring material management, in which the settings for the respective product are individually adapted, optimised and selected by the operator via dropdown menus. Customer-specific extensions are also optionally available for flexible growth with new requirements in the context of Industry 4.0.

» Flexibility and precise measurement up to the edge area

Many measuring challenges can be solved with the flexibility of the F5500 laser systems. High scanning speeds of up to several metres per second, measurements with material widths of over 4m, measurement of materials with complexly structured or translucent surfaces and measurements with high sampling and output rates.

Laser system with Triangulation Sensors for extra wide web-shaped materials

Laser system with Triangulation Sensors for extra wide web-shaped materials

The fields of application in the automotive and industrial sectors are as diverse as they are different. MESACON laser systems are ideally suited for online measurement of the material thickness of flat products and web-shaped materials. The systems providing non-contact and precise measurement up to the material edge, independent of material type, colour and coating, even when difficult surfaces are involved.

For other applications, MESACON offers a comprehensive product range of radiation based measuring systems, in addition to the laser-optical measuring systems product line.

We will be happy to advise you on the best possible solution for your measuring task.

Author: Martin Kuss

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