Plastics industry

Why is it color measurement so important in production ?

color is a primary quality criterion. If color a product is not the same on different surfaces, everyone immediately sees the difference. We decide within seconds whether a product appeals to us or not, based on the visual impression.

One color measurement in the laboratory is important, but provides the information too late to intervene in the running process in case of colour variations. Inline color measurementhelps the press operator to control his production process so that in the end a consistently good quality is always delivered to the customer.

color measurement of granules

Plastic granulates are the beginning of all further production steps. Whether base material or colored compound: When the colorIf the color, opacity or transparency does not fit, all further processing steps will also fail. That is why it is so important to check already in this phase color and other parameters and to maintain close tolerances.

What advantages does the inline measuring system offer

An occasional check by the laboratory is not enough to monitor and control production. If it changes color slowly, there will be rejects that need to be recycled.

Colour deviations must be detected at an early stage. This is the only way the machine operator can intervene in time and take countermeasures even before the tolerance limit is reached.

A non-contact color measurement with the ERX130 is installed on the sorting chute. There, the granulate already has a crystalline structure and thus corresponds to that ofcolor the end product. The special geometry of the ERX130 ensures that the granules are measured reliably, even if they are suspended on the vibrating chute or if the size of the individual grains changes. There is no need for time-consuming sampling and spraying of sample plates.

Fully automatic forwarding of the measurement results

In connection with a superordinate process control computer, the execution of measurement orders and the forwarding of the measurement results can be fully automated. Test reports are often required to prove the quality of a batch. The test records show diagrams which show the deviations of the parts color to be submitted and the uniformity of the colormeasured values over the course of production. Furthermore, the evaluations can contain information on whether batches can be processed together or how they are to be mixed.

erx130 inlin pellets
color measurement on plastic granules

Typical applications

Advantages at a glance

A system with certain advantages

Advantages of the Inline color measurement

Advantages of the X-Rite Inline System

Plastic Reflection measurement

Covering plastics are measured in reflection. It does not matter whether it is films, sheets, extruded profiles, fibres, multiwall sheets or injection moulded parts. The sample is illuminated and the reflected light is measured. The inline measuring instruments are robust, ambient light, dust and vibrations have no influence on the measuring accuracy. Therefore, even narrow tolerances (as required in the automotive industry, for example) can be maintained.

Turnkey systems

X-Rite supplies turnkey systems that are adapted to our customers' machines and their measuring tasks. Several colorimeters are available to solve the various tasks. Together with our customers we analyze the problem definition and develop an individual concept. Only in this way can a solution be offered:

  • Fits easily into the existing machine
  • provides the measurement results, which contribute to product improvement
  • The possibility of a Closed Loop Color Control offers
  • protocols and measured values to a superordinate system.

Selection of the measuring instruments

Measuring deviceGeometryDistanceMeasuring spotComment
ERX5045°:0°10 mm10 mmSuitable for stationary and traversing measurement, can also detect opticaloptical brightener .
ERX130coaxial300 mm90 mmSuitable for stationary and traversing measurement. Due to the large measuring surface (64 cm³!) especially suitable for structured and patterned samples.

45°:0°60 mm30 mmNo internal calibration, must be mounted ontraversing beam

What is the best solution?

Talk to us! You know your machine, your problems and your expectations, we are the specialists when it comes to inlinecolor measurement . Together we will find a solution that solves your colour problems.

Continuously measured

color measurement on plastic

You want a consistent colour result on your production machine? 

We would be happy to advise you!

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Plastic Transmission measurement

For the measurement of transparent foils or plates, if colorHaze and light transmission are important. These parameters can be influenced by adjustments on the production machine. In order to produce constant, good quality, it is therefore important to monitor these parameters continuously. Even the smallest deviations are recorded. The machine operator can immediately intervene in the process before production runs out of tolerance.

Especially with plastic sheets for architectural applications (e.g. PVC panes), a UV absorber layer is applied to prevent the pane from yellowing. This protective layer is very expensive, but a defined quantity must be applied for the expected service life of the pane. However, if too much is applied, the costs increase. Measuring the effectiveness of this protective layer guarantees a defined quality at minimum cost - the investment for the measurement is thus quickly amortised.

Reliable measurement results

The ERX55 encoder is mounted with the C-frame on a linear guide on the production machine. For regular, automated calibration the measuring instrument is briefly moved out of the track. Calibration is carried out in air, i.e. without material between the C-frame. This ensures reliable, stable measurement results.

If there is no material on the machine, the measuring device is also extended. This makes it easier to feed in the new material web. As soon as the web is running stable again, the measuring device moves into the measuring position and starts measuring automatically.


Measured values