Characterizing Novel Honeycomb Infill Pattern for Additive Manufacturing

Abstract

Prismatic closed cells, i.e., honeycomb structures, are often used as infill in additive manufacturing (AM) for providing physical stability to the skin and mechanical integrity to the object. These cells are periodic in nature and uniform in density. In this research, a new fabrication pattern for honeycomb infill is proposed for material deposition-based additive manufacturing applications. The proposed pattern uniformly distributes the material within the cell and can accommodate a controllable variational honeycomb infill while maintaining continuity with relative ease. First, the honeycomb unit cell geometry is defined for uniform and non-uniform voxel sizes. A continuous toolpath scheme is then designed to achieve the honeycomb structure with uniform wall thickness. Unlike traditional honeycomb cells, the aspect ratio of the proposed cell type is not restricted, which helps to introduce variational honeycomb architecture in the infill. Additionally, the proposed cell type is four-time smaller than the traditional cell, which increases the unit cell packing density for the same R3 space. The proposed infill structures are fabricated with both uniform and variational patterns, which are then compared with the traditional honeycomb pattern with compression testing. In comparison to the traditional samples, the proposed uniform and variational infill patterns have achieved higher elastic modulus, collapse strength, and absorbed more specific energy along the X-direction. However, the values measured for both proposed patterns are lower along the Y-direction. Similar results are achieved for two different materials (PLA and TPU), which indicates the consistency of our findings.