基于CAD系统的快速成形层片轮廓扫描数据的直接提取

为避免快速成形中采用CAD模型的转换模型造成层片轮廓扫描数据精度损失，研究了在CAD系统内部直接提取层片轮廓扫描数据的方法．分析了层片理论轮廓扫描边界中高次曲线的离散方式，定义了层片轮廓扫描面积偏差的概念，建立了CAD模型直接分层截面轮廓边界离散模型，实现了在CAD系统内部直接提取层片轮廓扫描数据，并在聚苯乙烯泡沫材料成形机上进行了试验．结果表明，CAD系统和快速成形系统之间可以避开三维CAD模型的STL转换等近似处理环节，从而获取高品质的轮廓扫描加工数据．

Direct extraction of contour scanning data of rapid prototyping layer within CAD system

In order to avoid the precision decrement caused by the approximate conversion of CAD model in rapid prototyping(RP),the method for extracting the contour scanning data of RP layer within CAD system was researched.The modes of scattering the complex curves of contour boundaries for RP layer were analysed,and the scattering deviation of that was defined.Based on which,the model of scattering the section boundaries of CAD model was established,and the contour scanning data of layer was directly obtained within CAD system.Finally,tests were conducted on a polystyrene foam cutter with example of layer generation.Tests show that the approximate processing to CAD model can be avoided during data transfer between CAD and RP,and the RP machine can be driven and controlled directly within CAD system.