Additive manufacturing of non-planar layers using isothermal surface slicing

Abstract

Most conventional additive manufacturing (AM) processes fabricate the designed 3D model in a planar-layer-based manner, which significantly limits the printing quality with poor surface roughness, weak strength, and wasting material and time for supporting structures. This study presents a heat-guided algorithm to generate non-planar layers using isothermal surfaces to address these drawbacks of planar layers. The designed model is placed virtually on a heated freeform substrate. The substrate's heat flows through the 3D model, which mimics the material accumulation in 3D printing. The “virtual” isothermal surfaces naturally slice a 3D model into curved layers. Different curved layers with desired functionalities can be created by tailoring the boundary conditions and the thermal conductivity for the “virtual” heat transfer problem. In addition, customized three-axis and five-axis 3D printers were prototyped to evaluate the proposed slicing method. Several test cases demonstrated the benefits, leading to a 63 % decrease in surface roughness, a 14 % increase in tensile strength, and a 50 % printing time reduction in multi-material 3D printing. Further, the presented non-planar slicing algorithm was utilized for conformal printing and to smoothen the printed parts with planar layers.