Investigating enhanced interfacial adhesion in multi-material filament 3D printing: a comparative study of t and Mickey Mouse geometries

Abstract

In this study, a novel design to enhance interfacial adhesion in multi-material components produced through filament 3D printing techniques is presented. Multi-material additive manufacturing often faces challenges related to poor chemical affinity between polymers and physical discontinuities between component sub-parts. To address these issues, an interface geometry that leverages both diffusion and mechanical adhesion mechanisms to facilitate interlocking is proposed. The performance of the widely used T-shaped geometry, as per existing literature, with a newly introduced Mickey Mouse lobate modified shape is compared. Additionally, the linear butt interface, which relies solely on chemical diffusion is investigated. For the study, Polylactic Acid and Polyethylene Terephthalate as the material pairs was selected. The findings underscore the significant impact of interface geometry on the mechanical properties of multi-material components. Using the ultimate tensile strength of the standard ISO 527-2 specimen as a reference, a butt interface results in a residual strength of 60% for homogeneous materials, but only 10% for heterogeneous materials. The adverse impact of the heterogeneous materials configuration was alleviated by the interfaces, leading to an enhancement of 7% and 58% for the Mickey Mouse and T geometries, respectively. While the Mickey Mouse geometry effectively reduces stress concentrations, it falls short of achieving the desired improvement in multi-material adhesion between parts. This outcome suggests the necessity of further research, particularly towards optimizing the proposed geometry for enhanced performance.