PSI - Issue 13

Ralf Lach et al. / Procedia Structural Integrity 13 (2018) 34–38 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

38

5

zone 2 indicated stable crack growth. The length of zone 2 decreases with increasing deformation in favor of zone 3 to be related to unstable crack growth i.e. brittle fracture. Furthermore, for a given deformation ( E x = 10 mm in this case) there is a linear correlation between the energy density used during the laser sintering process to manufacture the rings and the lifetime N B (Figure 4). Information about the influence of the processing conditions on the lifetime under cyclic loading can be obtained within a few days which is essential for fast quality assurance in practice.

2000 4000 6000 8000 10000 12000 Number of cycles at break N B

100 120 140 160 180 200 0

Energy density (Ws/cm 3 ) Fig. 4. Number of cycles at break ( N B ) as a function of the energy density; rotating bending: 250 min

– 1 ; deformation E

x = 10 mm; the straight line

is according to linear data fit.

Acknowledgements

The authors like to thank the Investitionsbank Sachsen-Anhalt (Germany) for funding the research project “ Prognose des Einsatzverhaltens 3D-gedruckter Bauteile mittels bruchmechanischer Ansätze ” ( FFD-Crack), project No. 1704/00066.

References

Blattmeier, M., Witt, G., Wortberg, J., Eggert, J., Toepker, J., 2012: Influence of surface characteristics on fatigue behaviour of laser sintered plastics. Rapid Prototyping Journal 18, 161–171. Grießbach, S., 2012. „ Korrelation zwischen Materialzusammensetzung, Herstellungsbedingungen und Eigenschaftsprofil von lasergesinterten Polyamid - Werkstoffen“ . Verlag Wissenschaftliche Scripten, Auerbach. Grießbach, S., Lach, R., Grellmann, W., 2010. Structure–property correlations of laser sintered nylon 12 for dynamic dye testing of plastic parts. Polymer Testing 29, 1026–1030. Grießbach, S., Lach, R., Grellmann, W., 2009. Der Rollringtest – Fortschritte bei der Bewertung der mechanischen Eigenschaften von laser gesintertem Polyamid. In: Proceedings (CD - ROM) of 12th Problemseminar Deformation und Bruchverhalten von Kunststoffen (24.– 26.06.2009), Merseburg, p. 309–315. Grießbach, S., Lach, R., Grellmann, W., 2008. Kleinserienfertigung hochfester Kunststoffbauteile. Kunststoffe 98, 29–32. Munguia J., Dalgarno, K., 2015. Fatigue behaviour of laser sintered nylon 12 in rotating and reversed bending tests. Materials Science and Technology 31, 904–911. Munguia, J., Dalgarno, K., 2014. Fatigue behaviour of laser - sintered PA12 specimens under four - point rotating bending. Rapid Prototyping Journal 20, 291–300. Van Hooreweder, B., Kruth J. - P., 2014, High cycle fatigue properties of selective laser sintered parts in polyamide 12. CIRP Annals – Manufacturing Technology 63, 241–244. Van Hooreweder, B., Moens, D., Boonen, R., Kruth, J. - P., Sas, P., 2013. On the difference in material structure and fatigue properties of nylon specimens produced by injection molding and selective laser sintering. Polymer Testing 32, 972–981. Van Hooreweder, B., De Coninck, F., Moens, D., Boonen, R., Sas, P., 2010. Microstructural characterization of SLS - PA12 specimens under dynamic tension/compression excitation. Polymer Testing 29, 319–326.