Investigating the reversible performance of shape memory composites in 4D printing using magnetic field stimulation: case study of polylactic acid/SrFe₁₂O₁₉ composite filament

4D printing is an advanced manufacturing technology in which the 3D printed structure evolves over time, and this evolution can be a change in appearance, change in material properties, or change in color. The controllability and reversibility of the 4D printing process have received little research attention. In this research, a combination of polylactic acid and microparticles of strontium ferrite (SrFe₁₂O₁₉) was used to create a composite filament. After printing and bending shape recovery, the reversibility of the printed parts was tested by N42 grade neodymium magnet and the reversibility of the parts was successfully done. The controllability of the shape recovery process was demonstrated through an experimental test using the obtained model. The difference of 3.65% between the experimental sample shape recovery and the amount of shape recovery obtained from the software shows the high accuracy of the presented model.