Study on Support-Free Printing of Large-Flow Material Extrusion Process

Support-free printing is one of the research hotspots of material extrusion process-based 3D printing. When printing bridge or suspended structures, the sagging of large-flow extruded material probably causes printing failure due to its big mass and fusion state. If the support is added, it is hard to remove because of its large adhesion with the matrix. Therefore, large extrusion flow printing process is more willing to print structures without support; the large and complex structures are often difficult to print. In order to realize support-free printing of bridge structure, this paper defines a concept of quantitative fusing segment and analyzes its dynamic balance characteristics during the pellet extrusion printing process. Then the printing speed reduction and air cooling scheme according to the analysis conclusion are put forward, and the experimental verification is carried out. The results show that the sag deformation of bridge structure can be reduced effectively, and it proves that support-free printing is feasible by the rapid cooling method.