A major challenge in FDM 4D printing is controlling the programming step, i.e., the residual strain introduction. The programming during printing leads to 4D printed structures, which change their shape, when their temperature is raised above glass transition temperature (Tg). The structures consist of thermo-responsive shape memory polymers, which are printed in a temporary shape and strive back to the permanent shape when heated above Tg. The amount of residual strain in the printed object depends on the printing parameters.
We measure the programming force lateral to the nozzle to determine the relationship between programming stress and residual strain. The measurement is a step forward to quantify the FDM 4D printing process. However, we show that the relationship between stress and strain also depends on the printing parameters. In conclusion, further effects must be considered. We suggest to add further sensors to quantify and control the programming step during FDM 4D printing.
F. Cerbe, D. Mahlstedt, M. Sinapius, C. Hühne, M. Böl
Relationship between programming stress and residual strain in FDM 4D printing
Progress in Additive Manufacturing, (2023) [Link]