Tne Research On The New Automatic Support Generation Techniques For Stereolithography

Stereolithography technology which has the earliest history in the Rapid Prototyping (RP) is the highest accurate and most extensive application in the RP field. Stereolithography supports techniques as some of the core techniques have a good sense in confirming the success of the process. However, the current major domestic techniques of auto-support generation algorithms are inefficient, especially in generating supports for complex models and tremendous number of facets in STL models which waste lots of calculating time and result in the delay of promotion and application of stereolithography system. In addition, as for the models with overhang features, the traditional models can't afford supports for them which lead to the failure of processing the parts. Therefore, the author has done some research from these following two aspects.Through researching traditional auto-support generation algorithms, the bottleneck factors which influence the efficiency of support generation algorithms have been found. The author puts forward a new auto-support generation algorithm based on discrete-marking method. This paper specifically demonstrates the discrete-marking principle, factors and the identified rule of self-adaptability discrete step criteria, and it also analyses the asymptotic time complexity and space complexity in auto-support generation algorithm based on discrete-marking method. On the base of testing as well as comparison in support generation efficiency of the famous rapid prototyping software abroad, this paper comprehensively evaluates the superiority of discrete-marking method for the auto-support generation algorithm.As the overhang features facets, the traditional auto-support generation algorithm fail to generate supports for them, so this paper tries to supply the support generation techniques based on researching the overhang points and overhang lines of STL models. In studying the Topology relation in STL models, the geometrical features of support needed facets with overhang points and overhang lines have been summarized. The algorithms are designed in order to draw the facets with overhang features according to the geometrical features. Two new support structures and their generation algorithms which give basis to the overhang points and overhang lines have been contrived. Furthermore, through lots of tests the accuracy of drawing the support needed facets with the overhang points and overhang lines and reasonableness of the support structures have been verified, which provide the new guarantee for the successful completion of parts.