Research And Development Of CAD Model Direct Slicing Software Facing To Rapid Prototyping And Manufacturing

Rapid Prototyping (RP) technology has been widely used because it can shorten product development cycle and decrease development risk, which enhance the market competitiveness of the product. RP is a kind of material processing technology which makes the product by adding material. The CAD (Computer Aided Design) model of the product should be sliced into layers in order to get the layer contour which would be used to generate the tool path. Computer Aided Manufacturing (CAM) software can be used to process the data of CAD model generated by the CAD modeling software such as Pro/Engineer, Unigraphics and so on. Model slicing method based on STL exchange data with CAD modeling software by using STL format file. The STL format file is widely used because of its advantages such as simple data structure and cross-platform compatibility. However it also has some disadvantages such as data redundancy, low accuracy, data errors and so on, which cause some inconvenience.Dealing with the problems of STL format file, model direct slicing method, which does not uses STL format file anymore, is used in RP software. Model direct slicing method slices the 3D model by calculating the intersection between the slicing plane and the parametric CAD model rather than triangulate the parametric CAD model into triangular meshes. The existing model direct slicing methods can be divided into two categories. One method is secondary development in CAD software. This method uses the Application Programming Interfaces (API) to calculate the intersection. The advantage of this method is the developer does not need to develop the intersection algorithm. It has high efficiency and good stability. The disadvantage of this method is it relies on specific CAD software and can not run without the CAD software. The independence and flexibility are limited. The other method is to develop the model direct slicing software out of any CAD software. The method has good independence and flexibility but it is difficult to develop the intersection algorithm. Model direct slicing method is used in this paper to avoid the disadvantages of the STL format file. In order to make certain of the independence and flexibility of this method, IGES format file and STEP203 format file, which can be generated by any existing CAD modeling software, are used to exchange data between CAD modeling software and the model slicing software. Open CASCADE modeling kernel is used to make the development easier and the more efficient. The model direct slicing software based on this method imports IGES format and STEP203 format file and implement the model slicing and path planning. The data file which can be accepted by the RP machine is generated by the software to control the manufacturing process.