Research On Digital Processing Of Multi - Material Parts Based On 3D Printing Technology

Due to the daily increase in complexity of industrial manufacturing, international competition and market globalization, the single-phase or homogeneous parts are difficult to meet the needs of the functionality or performance of the products. The limitations of traditional single-material homogeneous processing technology have already been transcended by multiple material additive manufacturing. Different materials on the same or different slice can be built to improve the parts’ performance, which attracts much more researchers to focus on this field.A designing and manufacturing data processing method is proposed for multiple material objects which based on the droplet injection technology and rapid prototyping technology. Parts with multiple composite materials, functionally graded materials, or colorful and color surface texture mapping can be manufactured directly. Some key technologies of multiple material additive manufacturing data processing are studied by this paper, the main studies in this paper are listed as follows:(1) The isolation between multiple material modeling theory and parts manufacturing is a serious issue that must be investigated, an appropriate output data format of a multiple material object for a corresponding three dimensional printing generated by this paper. By comparing several existing standard format files, a high-precision color PLY file 3D model is selected as a format that can obtain a rapid and precise geometric reconstruction process of multiple material objects and ensure the orderly storage of data.What is more, the compatibility with three-dimensional printing is the prominent advantages of the PLY file format.(2) An approach is presented by this paper to represents a multiple material object by material control functions and slice contours. The modeling method is divided into two steps. Firstly, material control functions are associated with the point clouds defined by 3D model grid nodes along Z plane. Secondly, the modeling method uses the concept of the material slice across X-Y plane. Through the mapping between material control function and the two-dimensional slice contour, the slice contours are divided into sub-regions of constant material composition, the material composition at any location can be calculated from the control functions.(3) One slicing algorithm based on the topological hierarchy of the color and texture model is presented. The algorithm not only can obtain the intersection point of the geometric coordinates and color values, but also can effectively identify and reconstruct internal and external contours for material region automatically, which lays a foundation for its further data processing.(4) The test based on the development of molding system for multiple material objects shows that the modeling method can be effectively solve the material definitions for multiple material objects which contains a variety of materials. This provides an effective method for the integration of designing and manufacturing for multiple material objects.Finally, the main work and innovation are summarized, and the further research work is proposed as well.