2D In-situ Investigations of Polymer Foams by Means of Radiography and 3D Structural Analysis by means of X-ray Computed Tomography

This work is concerned with creating a setup for ink application onto foam materials of two stamp systems and their sub systems and the investigation of their time dependent ink absorption behaviour. The absorption behaviour is determined by two-dimensional in-situ investigations (2D radiography). For correlation, three-dimensional structural analysis (3D computed tomography) is performed. For both non-destructive investigation methods, a microfocus X-ray computed tomography device was used. The foam and fibre structures of the systems components are manufactured of different kinds of plastics. A fundamental question for printing systems is wetting, edge impregnation and the uniformity of ink distribution within materials and components and the transition between them. An ink application setup was developed, that was placed inside the CT device. Optimal parameters for ink application were determined for different material systems. In-situ investigations, using 2D radiography with different inks and additional proceeding of statistics, made the determination of the best features possible. The 2D in-situ results showed differences in ink penetration behaviour between material systems and between the distinct sides of the specimens. The quantification of the heterogeneities by structural analysis and thereof obtained statistics of pore size and shape factor distributions gave a reference for the results of the in-situ investigations. The correlations of the 2D and 3D results lead to the insight, that the materials surface and structure as well as the used ink, influence each other in a very specific way.