A Feasible Study on the Application of Cyclic Annealing Treatment for Functionality Improvement of 3D Printed PLA Parts

Abstract

In the 3D printing of polymeric parts, the annealing cycle is a post-process method that allows different polymeric materials to enhance their mechanical and thermal properties and also eliminate their residual stresses. However, annealing has some drawbacks, such as producing induced shrinkage to the treated parts. In this study, a new technique named “cyclic annealing” is proposed to reduce shrinkage due to annealing treatment. By subsequent increasing and reduction of the temperature over and below the glass transition temperature instead of suddenly increasing the temperature to the target annealing temperature, a significant reduction of shrinkage was observed for the printed PLA parts. Various cylindrical shape samples with different infill densities (30%, 50%, 70%, and 100%) were examined at 70°C, 90°C, and 110°C annealing temperatures. Considerable reduction of shrinkage by up to 50% and improvement of the material strength were observed, which confirms the applicability of the proposed cyclic annealing method as an alternative to traditional polymer annealing for 3D printed materials.