Check out this case study. This is just one example of what computed tomography can do for you.
The German Plastics Centre SKZ in Würzburg takes a leading role for the industry in the development of new fiber-reinforced materials. SKZ not only uses state-of-the-art manufacturing methods, but also new technologies in the field of metrology and testing. For different problems and quality analysis two exaCT computed tomography systems from WENZEL Volumetrik are in use.
The Plastic Center´s fields of activities are varied. Next to a wide range of seminars and training courses for experts and managers and analyses and testing of plastics and products, SKZ’s department of research and development develops and tests new fiber composite materials . An example for these developments is the so called Wood Plastic Composites (WPC).
Wood-Plastic-Composites are novel thermoplastic processible reinforced materials. They can consist of different portions of wood, plastic and additives. They are often used in the construction sector, but also in the automotive and furniture industries. These materials distinguish themselves by their excellent three-dimensional plasticity.
Compared to derived timber products WPCs have high resistance to humidity and ultraviolet light and have a signifi cant greater stiffness compared to unreinforced plastics. To produce saleable products like window frames, housings, end plates, connecting components for kitchens or coverings in the automotive joining methods have to be used. Currently welding and adhesive bonding as joining methods are tested. Errors in the joining area can turn the welded joint into a weak spot of the WPC-part. This would affect the durability dramatically. Consequently there is a great interest in the plastics industry in testing thermal and adhesive joined components.
The exaCT® computed tomography systems at SKZ are used for the analysis of welded joints of wood fiber composite materials. With CT data the quality of welded joints can be evaluated. Critical criteria are the spatial orientation of the wood particles, voids, inclusions and the substance-to-substance bound of the seam.
The exaCT® computed tomography systems at SKZ
are used for the analysis of welded joints of wood fi -
ber composite materials. With CT data the quality of
welded joints can be evaluated. Critical criteria are
the spatial orientation of the wood particles, voids,
inclusions and the substance-to-substance bound of
Figure 3 shows a sectional view of a test object made
of wood fiber composite material (figure 2). This object is joined by ultra-sonic welding. The material mix and the wood fiber have different densities.
Therefore, the wood particles are clearly visible in the plastic component of the WPC (figure 3). A visual analysis of these sectional views allows an evaluation of the quality of the welding joint.
If the wood particles are perpendicular to the welding seam it is most likely that it results in greater stiffness. Whereas where they are parallel to the welding seam, oriented wood particles suggest a less stiff bonding.
Defects in welding seam are analyzed in the following
stage of the analysis. The evaluation software can recognize inclusions automatically and assign them to
different categories of size by color coding (figure 4).
The method makes a complete and non-destructive
analysis of defects through the evaluation of the number, distribution and size of inclusions occurring .
The results of the analysis are used for the evaluation
of quality and applicability of the combination of
wood fiber composite material used and the joining