Research Of Key Technologies On Heterogeneous And Multiple Materials Rapid Prototyping

Additive Manufacturing (for short, AM), which is also called Additive RapidPrototyping, is a layer-by-layer manufacturing technology. Since it was proposed in1970s, many researchers in this field focus on Rapid Prototyping technology of singlematerial part. In recent years, to satisfy increasing complexity requirements ofindustrial product and flexibility, high efficiency requirements required byglobalization of markets, Multiple Material Additive Manufacturing(for short,MMAM) technology is proposed and attracts much more researchers to focus on thisfield quickly. MMAM technology can fabricate objects with complex materialattribution and geometry attribution, as well as more functions, for example,Functionally Graded Material (FGM) objects, Composite Material (CM) objects andtheir combination and so on. MMAM technology can build different material on thesame slice to improve part performance, which cannot be realized by traditionalmanufacturing technology.This dissertation studies some key technologies of Heterogeneous and MultipleMaterial Rapid Prototyping (HMMRP) and proposes some algorithms in this field.The main research works and achievements of this dissertation are listed as follows:(1) Subdivision algorithm has been studied. Firstly, proposes a new topologicalinformation structure for STL(StereoLithography) model, and then Hermite spacecurve interpolation method is applied to realize the subdivision for STL mesh model.The number of triangles of new STL model increases4ntimes (n is the subdivisionnumber). Thus, the subdivision algorithm can improve the surface accuracy of STLmodel quickly.(2) Presents a new efficient slice contour construction algorithm (ESCC-algorithm), which has two main features—efficiency and distinguishing inner andouter contour for material region automatically. Meanwhile, a new slice algorithmbased on ESCC-algorithm is presented. Comparison experiment results and algorithmefficiency analysis demonstrate that the algorithm can improve greatly the slice andits contour construction speed.(3) Proposes a computer representation method for Heterogeneous and Multiple Material Object (HMMO) by mapping object and material based on manufacturingprocess. The representation method can be used to represent the geometry attributionand material attribution efficiently. To realize the above representation method, amaterial region construction algorithm (MRC-algorithm) and an optimizedaccelerated algorithm (OA-algorithm) for MRC-algorithm is proposed. Comparisonresults demonstrate the OA-algorithm can obviously accelerate MRC-algorithm.Meanwhile, a Multiple Material Additive Manufacturing File (MMAMF) format isalso proposed with much more explanations.(4) Presents an irregular discretization method for Multiple Functional GradedMaterials (MFGM) objects and comparison experiment is implemented comparedwith some existing technologies. Material attribution calculation method fordiscretization cells is provided to realize the MFGM object visualization.(5) The Rapid Prototyping method of CMs Object has been studied. To avoidnozzles collision, a nozzles planning method is provided. Meanwhile, studies theRapid Prototyping method of one and two FGMs object, and the correspondingexperiments is implemented. Further, presents the Rapid Prototyping method ofmultiple FGMs object.The innovations of this dissertation are listed as follows:(1) One slice contour construction algorithm with high efficiency is presented.The algorithm can distinguish inner and outer contour for material regionautomatically which is the pre-condition of the optimized accelerated algorithm(OA-algorithm) for MRC-algorithm.(2) A Multiple Material Additive Manufacturing File (MMAMF) format ispresented to represent the geometry attribution and material attribution efficiently forHeterogeneous and Multiple Material Object (HMMO).(3) An irregular discretization method is proposed for Multiple FunctionalGraded Materials (MFGM) objects visualization.