MULTI-MATERIAL FDM 3D PRINTING PROCESS PARAMETER DEVELOPMENT BASED ON BENDING TEST CHARACTERIZATION

The purpose of this investigation is to study the effects of perimeter inflation on the dynamic behavior of a flexible / rigid multi-material interface. The results of this study can be applied to applications where there is a need for low cost, multi-material 3D printed parts which have both flexibility and strength at the material interfaces designed to undergo simultaneous axial strain and flexural strain. A non-homogeneous 3D printed structure with the desired static and dynamic mechanical behavior was designed using a flexible thermoplastic polyurethane substrate (NinjaFlex) and stiff ABS segment. The multi-material part was printed using a consumer grade dual extruder desktop FDM 3D printer. This project focused on the evaluation of the mechanical behavior of the 3D multi-material due to delamination at the interfaces between the materials undergoing simultaneous flexural and axial loading. In order to reduce the occurrences of delamination, overlap at the interfaces was imposed by using perimeter inflation of both the two different materials. The purpose of the project was to develop a test methodology for the evaluation of the use of perimeter inflation in order to improve the behavior of the multi-material fused deposition printed parts. A modified 3 point bending test was developed to measure the equivalent stiffness and internal damping of the material interface. As a result of this testing, increasing the perimeter inflation was found to cause a modest increase in the stiffness of the interface, with little effect on the internal damping of the interface.