Research On Theories And Application Of Free Curved Surface Design And Rapid Prototyping

With the increasingly rigorous market competition, production cycle and price of products have become the crucial factors for enterprises. Therefore, the technology and method to enhance the productivity and reduce the production cost have been highly considered by enterprises. As a result, Rapid Prototyping(RP) has been recognized by most of modern enterprises due to its advantages of rapidly fabricating complicated prototypes and reducing the production cycle. Based on the consideration mentioned above, this paper analyzed the principle and characteristics of FDM as well as the key factors to affect the molding result, and pointed out the influences of surface reconstruction and slicing direction in FDM on the production efficiency and the cost saving. An outline to establish the software system was presented for FDM RP. Two aspects were researched. On the one hand, the edit points instead of vertexes to be used in the surface reconstruction in order to reduce the calculations and improve construction efficiency. On the other hand, the slicing direction was researched to decrease the amount of support material for lower cost.Based on the NURBS theory, the different functions as well as their inner links between edit points and vertexes were analyzed. The existing methods for surface reconstruction were compared. Then a new method for reconstruction was presented by using edit points directly instead of vertexes and the related characteristic parameters of the surface were extracted. The software module was developed for surface reconstruction.In order to reduce cost, RP methods and support technique were studied theoretically and a method was presented to determine the optimal slicing direction. By abstracting the maximal boundary contour of the object in CAD software and comparing the volumes of the support material in different directions, the optimal slicing direction was determined. A software was written by using VB and Solidworks. As a result, the optimal slicing direction could be obtained automatically for free form surface objects.Finally an example was given to prove the validity of the methods proposed in this paper. The result shows that the developed modules for surface reconstruction and slicing direction optimization are feasible. They have the practical value to enhance efficiency and reduce cost in production. In addition, the combination of developed modules with the existing 3D software will provide a helpful tool for the designers to control the modeling and production process.