Izi-Direct – Innovative non-destructive method for inline characterization and quality assurance of discontinuous recycled carbon fiber semi-finished products

The figure shows the measuring device from the company Suragus, which is used at Fraunhofer IGCV for eddy-current measurement.

A special sensor from Suragus allows the orientation of the carbon fibers in the nonwoven to be determined. This is a decisive parameter since the orientation of the fibers is decisive for the mechanical properties of the CFRP component produced from the nonwoven.

Eddy current measurements were used to determine the orientation of the carbon fibers in UD material and isotropic carbon fiber nonwoven. The shown polar diagrams show results of example measurements.

In addition to the orientation of the carbon fibers in the nonwoven, the homogeneity, basis weight, and fiber volume content of the nonwoven will also be monitored during production to increase the quality of nonwovens made from recycled carbon fibers. The eddy current sensors are evaluated and assessed through the research partners ITA Augsburg and Fraunhofer IGCV, both located at the Augsburg Technology Center and have strong contacts in the carbon fiber processing industry. The procedure of Fraunhofer IGCV is exemplarily shown in the following figure. On the one hand, the eddy current sensor can be used to evaluate the homogeneity of nonwoven pieces. On the other hand, a calibration curve can be determined from many nonwoven pieces, providing a basis for the inline application.

In addition to the sensor evaluation, the partner CIKONI is developing a simulation method for predicting the mechanical material properties based on the measured parameters and comparing them with the real behavior of carbon fiber plastics made from rCF nonwovens.