Reduction of the residual warpage of fused deposition modeling by negative thermal expansion filler

Abstract

We investigated the suppression of residual warpage using a negative thermal expansion (NTE) material filler, Zn_1.6Mg_0.4P₂O₇. To focus on the effect of thermal expansion on residual warpage, we used acrylonitrile-butadiene-styrene, which is an amorphous polymer with a small volume change around the liquid–solid phase transition, as the matrix. Composite pellets were prepared using a kneader, and filaments were produced for fused deposition modeling (FDM) using an extruder. We fabricated a bar-like test piece using a standard FDM machine and measured the warpage deformation using 3D scanning. The experimental results were supported by the finite element method. We also compared similarly sized SiO₂ powders to discuss the advantages of NTE over conventional fillers. The warpage of a 100 mm x 5 mm x 2 mm bar-like test piece was reduced by approximately 75% by introducing Zn_1.6Mg_0.4P₂O₇ at 40 vol%. The effect of Zn_1.6Mg_0.4P₂O₇ at 30 vol% is similar to that of a conventional SiO₂ filler at 40 vol%. Reducing the residual deformation through fillers would reduce energy consumption and simplify the device by avoiding build stage and chamber heating.