Fused deposition modelling (FDM) is an additive manufacturing (AM) process which can be used to manufacture transforming structures, known as “4D printing”. Thermoplastic shape memory polymers (SMP) allow printing a structure in a temporary shape, which can later be activated by exposing the structure to heat. By adjusting various printing parameters and structure layup, different geometries and transformation performance can be achieved.

The different materials and printers being used in studies creates a problem in comparability and reproducibility of research results. The step forward is the proposed process model, where influencing parameters along the process are discussed. It provides a guideline for four sections: Material selection, Structure Design, Printing, and Activation. The complex influences are shown in a time temperature stress diagram and compared to the Shape Memory Cycle.