Online process monitoring allows immediate feedback and closed-loop manufacturing of carbon fiber materials. The EddyCus® inline ISO provides isotropy data for the continuous roll-to-roll process of recycled carbon fiber, UD-tapes or similar configurations. The solution offers real-time data across the entire width of the web at a competitive price.

The EddyCus® inline ISO is an inline solution for recording the fiber orientation and fiber areal weight of each fiber layer of an entire stack. This allows you to react immediately and realign the layers as soon as deviations from the target are detected. The monitoring system can monitor the fiber layer at various angles e.g. 0°, 90°, -45° or 45° at one or more lanes at a single point. It compares the polar plot of a reference with the polar plot of a currently produced ply, checking the difference in the angles of the inflection points and also the length of the plots. This gives you the information you need to determine the quality of the product and monitor the production process – the orientation of the layers and the fiber area weight of each layer. The picture on the right shows an example of a possible visualization of a two-layer stack. The black line shows the expected values determined by a reference and the red line corresponds to the values of the measured stain.

How can the polar diagram shown on the right be interpreted?

• The orientation of the fibers corresponds quite closely to the expected value. This can be seen from the fact that the inflection points of the reference and the examined material have the same angle.
• The fiber area weight deviates significantly from the desired result. This can be seen from the distances of the inflection points from each other.

The example is constructed, but it shows how easy it is to interpret the data using the SURAGUS solution.

Carbon Fiber Layer Separation

By using SURAGUS sensors, the individual, real bonded plies can be virtually separated from each other and analyzed. The sensor signal penetrates deep into the carbon fiber ply and can distinguish up to 10 plies. The separation works primarily by fiber orientation. If there are several plies with the same fiber orientation, the separation of a single ply is no longer possible. Instead, the layers with the same fiber orientation are combined. This procedure comes closest to the real requirements of the material.

SURAGUS sensors only take into account the carbon fibers. The resin or any other adhesive is not detected by our sensors.

Fiber Orientation

Fiber orientation is one of the most important properties of a carbon fiber component loaded in tension. The fiber orientation directly determines the load limit. This is why the correct angle of the bonded plies is so important.

SURAGUS sensors are adjusted and optimized for the angle to be detected. Each angle to be examined receives its own sensor. The distances between the individual sensors are calculated out to obtain a result that is accurate to the point.

Fiber Areal Weight

The SURAGUS sensors detect two main measured variables. The angle and the strength of the signal. The strength of the signal allows conclusions to be drawn about the amount of material in the direction under consideration. As shown in the picture, a higher amplitude means a higher surface weight and a lower amplitude means less surface weight. Through our sensors, they will not be able to determine the exact basis weight. Our sensors are calibrated to a target value and relate the measured material to the target value.

How well this works depends very much on the composition. If several layers point in the same direction this is challenging for the analysis. The concept works very well in this case, but due to the missing possibility to separate the layers, only the total weight per unit area can be displayed. This leads to the fact that no recommendations for action can be derived to bring the process to the target values. Contact us to evaluate the applicability in your application.

Defects Within a Layer

By separating the different layers, individual defects within a layer can be detected. These include gaps or, as shown in the image on the right, waves.

Easy to Use Software

The software is easy to use and clearly displays the recorded values. A report can be created for each roll and can be handed over to the customer as proof of quality.

Demo Measurement To Show Feasibility

To give you an idea of the performance of eddy current technology, we offer you a free demo measurement.

The process goes something like this:

1. You contact our sales team and describe your application case
2. We evaluate whether the eddy current technology is suitable for your application
3. For highly innovative materials a non-disclosure agreement can be made in advance
4. You send us your samples
5. We measure your samples
6. We contact you and discuss the measurement results together

Typical Use Cases of the EddyCus® CF inline ISO

• Online fiber distribution and fiber areal weight (FAW) measurement of non-woven mats
• Material flow analysis of carbon fiber SMC (vector – fiber orientation, level of alignment, isotropy)
• Online & offline process control of fiber orientation in non-wovens and discontinuous carbon fiber
• GDL (gas diffusion layers) are continuous non-wovens with high quality specifications regarding uniform fiber distribution (FAW)
• Characterising recycled carbon fiber from production scrap
• Development engineers for material flow of discontinuous carbon fibers (e.g. chopped or cut CF and press process)

For more information please watch our data sheet or contact us by email.

Data Sheet for EddyCus® CF inline ISO