A Volumetric Difference-based Adaptive Slicing and Deposition Method for Layered Manufacturing

Abstract

Adaptive slicing capable of producing variable thickness is a useful means to improve the fabrication efficiency in layered manufacturing (LM) or Rapid Prototyping (RP) processes. Many approaches have been reported in this field; however, most of them are based on the cusp height criteria, which is not an effective representation of the staircase effect when the surface normal is near vertical. Furthermore, most of the existing methods slice the model without considering the local features in the plane of the sliced layer. This paper introduces a novel difference-based adaptive slicing and deposition method. The advantage of this slicing method is that the slicing error is independent of the surface normal. A new criterion for adaptive slicing is evaluated and compared with that based on cusp-height. An adaptive slicing algorithm, which uses the volumetric difference between two adjacent layers as the criterion for slicing, has been developed in this work. Different deposition strategies for the common area and the difference area are applied to layer fabrication while considering the local features of the sliced layer. The algorithm has been tested with a sample part, and the results indicate that a better surface finish can be achieved for both surfaces whose normals are nearly in the slicing plane and surfaces whose normals are nearly perpendicular to the slicing plane. It is found that the building time can be reduced by 40% compared with the traditional adaptive slicing. The proposed method has minimized the volumetric error between the built LM part and the original CAD model while achieving a higher efficiency. It is suitable for most commercialized LM systems due to its simplicity in implementation.