Rhenowave®: Representative inline quality control for the production of rubber compounds!

About Rhenowave®

Controlling the quality of rubber compounds!

The compounds are analyzed during extrusion (for example during straining or shaping) in a pulse transmission process with the help of ultrasound waves. Fillers such as carbon black and silica have characteristic attenuation properties for sound wavesparticularly in the range of 1 MHz to 20 MHz, so that the filler content can be determined with a precision of up to 1 phr. Unlike with many other analytical methods that use electromagnetic waves, carbon black does not disturb this process. As a result, even black compounds can be volumetrically analyzed. Owing to the sound scattering, large inhomogeneities (> 10 µm) can also be determined. Using a marker with a high density, e.g. zinc oxide, the distribution of Rhenogran® AP additionally can be monitored. Rhenogran® AP products are customer-specific additive packages made from crosslinking chemicals, and are polymer-bound, dust-free and easily dispersible. Rhenowave® is fast, both used alone or in combination with Rhenogran® AP. Following the exit of the compound from the extruder, an assessment of the compound quality is performed within a few seconds (inline control). Where array technology is used, up to 100 percent of the compound can be analyzed. Small areas where compound quality is insufficient are recognized immediately rather than later in the product. The method is representative. With the aid of special ultrasound transducers, transduscer distances of between 5 mm and max. 30 mm can be realized, depending on the compound and the compounding temperature T > 100 °C. This means that Rhenowave® can be used in a production scale of 1,000 kg/h. Rhenowave® is absolutely non-destructive.

On account of rising competitive pressure in the rubber processing industry, production processes are increasingly being accelerated to achieve higher productivity. “At the same time, the demands on the quality of rubber compounds also are on the rise,” says Dr. Andreas Schroeder, resposnible for the development of Rhenowave®. “To ensure low reject rates even under these conditions, the content, dispersion and distribution of the fillersand the crosslinking chemicals must be evaluated rapidly and in representative fashion,” he adds.

Today, rubber compounds usually are characterized by their Mooney viscosities, their crosslinking behavior and stress strain curves. These tests are destructive, meaning that only a very small percentage of the rubber compound < 0.1 % is tested. This kind of sampling therefore is not representative, but rather random. Areas displaying inadequate compound quality frequently are not detected. In addition, quality control is carried out offline, minutes, hours or even days after the compound is manufactured. As a result, errors in the compounding process are not identified until a late stage, let alone eliminated, so that in the worst case scenario rejects continue to be produced.



Controlling the quality of rubber compounds!

Rhenowave® is a new quality control concept for rubber compounds presented by Rhein Chemie. The compounds are analyzed during extrusion with the help of ultrasound waves in a pulse transmission process. The reason: quality and cost-effectiveness are factors of equal importance in the manufacture of rubber goods.


Find out what LANXESS offer and what are the main benefits for you in our FAQ.

What is the technique behind Rhenowave®?

Rhenowave® uses pulses of ultrasound. To perform ultrasound measurements, electrical signals are converted into mechanical oscillations in an ultrasonic transducer (emitter) with frequencies in the MHz range. The mechanical oscillation generate pressure waves p(x,t) which are transmitted through the rubber compound. The transmitted waves are detected at a second ultrasonic transducer (receiver), where the pressure waves are reconverted into electrical signals. The attenuation of the ultrasonic pulse is characteristic for the given rubber compound.

What are the interface and the output of Rhenowave®?

After calibration of Rhenowave® related to the customers recipe the response of the signal is without any delay. The signal of Rhenowave® is demonstrated on a separated screen, which means the operator is able to act immediately if the quality of the compound does not fulfill the requirements.

What is included in the delivery package of Rhenowave®?

Our customer gets all relevant technical goods (sensors, pc, interface connection, screen…) as well as software for signal detection and interpretation that Rhenowave® can be used with all its facets. Beside that Rhein Chemie Additives offers the service to install Rhenowave® and to train our customer for using it.

What is making the application of Rhenowave® for rubber compounds so challenging?

Elastomers filled with Fillers (e.g. carbon black, precipitated silica) have high attenuation properties. Another challenge is due to rubber processing, where variation of measurement conditions, especially pressure and temperature, during extrusion occur and has a small but significant influence of the ultrasound signal.

Does the customer have to buy new equipment for using Rhenowave®?

In general this analytical device has a broad range of application, from extrusion of finished goods up to stand alone machine. The needed equipment for the use of Rhenowave® does not vary and is reduced to the attachement of the delivered transducer to the already existing process.

Who will install Rhenowave®?

The service we provide to our customers includes the installation of Rhenowave® and train the operator to produce first results with their implemented process equipement.

Is it possible to use Rhenowave® as a laboratory device?

The principle behind Rhenowave® needs to squeeze the compound between the ultrasonic transducers. In other words the rubber needs to be in motion to obtain volumetric measurement results.

What can LANXESS do and for whom?

Rhenowave® is useful for every kind of quality improvement, e.g. compounder to reduce scrap rates by process optimization or profile extrusion to realize zero defect policies, or simply as laboratory equipment to get a better understanding of the mixing process.

Further benefits for your customers?

Due to the new analytical approach the customer will get a deeper understanding of their rubber compounds and will therefore be able to increase the quality. Additionally the values of the signal are recorded on a hard disc which means that the customer is able to track the quality of the compound even after long time.

What distance between the ultrasound transducers can be realized in an extrusion process?

The distance between the ultrasound transducers (emitter and receiver) depend on the rubber compound and processing parameters like pressure and temperature. However, in general the possible distance should be between 5 and 30 mm.

Benefits at a glance

Inline analytics for rubber compounds

Technical characteristics

  • homogeneity
  • Wide range of application
  • Impurity detection
  • External data storage
  • Network connection


  • Free Software Update
  • Help for installing & integration

Quality & Cost Control

  • Cost savings through lower scrap rate
  • Non-destructive testing
  • No delay of response
  • Representative results


Here you can find a list of relevant publications.

  • Inline-Qualitätskontrolle von schwarzen Kautschukmischungen
    L. Gräff, A. Schröder, L. Wawrzinski, Teil 1: Füllstofftyp und –anteil“ GAK 10 (2013) 695
  • Volumetric inline quality control for production of rubber compounds
    L. Gräff, A. Schröder, L. Wawrzinski, Rubber World 251 (2015) 28
  • Better to hear than to see
    L. Gräff, A. Schröder, L. Wawrzinski, KGK 68 (2015) p. 10.
  • Vernetzerbatches, enthaltend markierende Substanzen, neue vernetzbare Kautschukmischungen und ein Verfahren zu deren Herstellung und deren Verwendung
    A. Schröder, V. Meenega, M. Säwe, EP-B 2314442
  • Verfahren zur Bestimmung der Qualität von unvernetzten Kautschukmischungen sowie eine entsprechende Vorrichtung
    A. Schröder, L. Wawrzinski , L. Gräff, EP-A 2736698

Meet the Team

Questions about our services? Contact us now!


Dr. Benjamin Bechem

Marketing Manager, New Technologies

Phone: +49 (0)621-8907-550 +49 (0)621-8907-550
Mobile: +49 (0) 175-31-40550 +49 (0) 175-31-40550
Email: Benjamin.Bechem@lanxess.com


Dr. Andreas Schröder

Specialist Application Technology, Lead Developer Rhenowave

Phone: +49 (0)621-8907-704 +49 (0)621-8907-704
Mobile: +49 (0)175-31-40704 +49 (0)175-31-40704
Email: Andreas.Schroeder1@lanxess.com


Lars Wawrzinski

Specialist Application Technology, Software Engineering Rhenowave

Telefon: +49 (0)621-8907-549 +49 (0)621-8907-549
Mobile: +49 (0) 175-31- 40549 +49 (0) 175-31- 40549
Email: Lars.Wawrzinski@lanxess.com

Dr. Bechem

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