The Method Of Filling Path Of Consistent Thickness Section Based On FDM Of Rapid Prototyping

Rapid Prototyping, short for RP, is obtained from the principle with integral method of 3D entity manufacturing, which is based on build-up and discrete idea. RP break through the traditional techniques"subtracting material", on the basis of 3D design model, slice at its height direction to obtain each layer interface profile; and then, fill up layer by layer, overlying along the height, finally shape up the 3D model.The Rapid Prototyping of FDM can only read STL at present, while STL is formed by many triangle plane slices to show CAD model data file, it leads to geometric distortion. Two-dimensional sheetlike layers are polygons formed by linear together, which also make geometric distortion. Because of these reasons, the surface accuracy of RP is kind of inaccurate. What's more, the cross section, especially the thin-wall section, filled up by parallel lines, trajectory is not continuity and uniformity. Physical properties and accuracy of the final model suffers from many limitations.It is obvious that STL format suffers from many limitations, this project is to explore a direct way to slice CAD model, and direct slicing in the software through the second developing tool of AutoCAD, 2D profiles of the layers is smooth curve which can guarantee the accuracy of prototype. According to consistant thickness of thin-wall kind parts, suggest to use two fill paths to mixed filling of Z direction, filling with parallel lines in odd-layer, and contour trajectory offset lines in even-layer. ObjectARX2002 is the second developing tool of AutoCAD2002 which can work out software on VC++6.0. The final software can simulate two fills, and calculating the length of filling path. Through analysis of the results, it not only avoids the limitations, but also improves the efficiency of RP. On the base that does not raise cost, this project raises model efficiency, accuracy and good performance, and provides the feasiblity of RP.