基于FDM工艺快速成型技术中均匀壁厚截面填充方法研究

发布时间：2018-02-26 03:20

本文关键词： 快速成型直接分层混合填充均匀壁厚填充路径　出处：《内蒙古科技大学》2011年硕士论文　论文类型：学位论文

【摘要】：快速成型技术(Rapid Prototyping，简称RP)，又称快速原型制造技术，是基于离散/堆积的成型思想，用积分法原理来制造三维实体的。RP技术突破了传统加工中“减材料”的工艺方法；将计算机上建模的零件三维CAD模型沿高度方向按一定厚度分层切片，得到每层的截面信息；然后输出到快速成型设备上逐层填充，再沿高度方向上粘结叠加，逐步成型三维实体。目前市场上FDM工艺的快速成型系统只能读取STL格式文件，，而STL格式文件是CAD模型的近似表达，即用一系列三角形平面片近似的表示CAD模型的数据文件，本身存在零件的几何失真现象。基于此格式进行分层得到的二维层片是由直线段相连而成的多边形轮廓，使得模型层片信息也存在几何失真，从而导致快速成型件表面精度比较差；再有目前截面内部填充均采用平行的直线段，对于薄壁类截面的填充，生成的填充路径呈锯齿形，还存在不连续和不均匀现象，使得成型件存在壁厚不均匀、物理性能差等问题。针对基于STL模型分层所产生几何失真的问题，本课题提出直接对CAD模型进行分层，并通过AutoCAD二次开发工具实现了在软件中的直接分层，所得层片的二维轮廓为光滑曲线，从而保证成型件精度。针对均匀壁厚薄壁类零件截面内部填充轨迹的问题，本课题提出在Z方向采用两种轨迹混合填充的方法，即奇数层采用平行的直线段填充，偶数层采用轮廓轨迹偏置线填充；并通过AutoCAD2002二次开发工具ObjectARX2002在Visual C++6.0开发平台上实现软件的开发；运行编制好的软件可在AutoCAD2002中实现这两种轨迹的模拟，并分别计算填充路径的长度；通过显示结果分析，这种方法不仅缓解了平行线填充带来的一系列弊端，同时在很大程度上提高了快速成型效率。通过本课的研究，实现了在不增加成本条件下，提高成型效率、制件精度和完善成型件性能，从而为下一步扩展到快速成型设备提供可行性。
[Abstract]:Rapid Prototyping, also called Rapid Prototyping, is based on the idea of discrete / stacking. The 3D CAD model of the parts modeled on the computer is sliced along the height direction according to a certain thickness, and the section information of each layer is obtained, and then output to the rapid prototyping equipment to fill layer by layer, and then it is bonded and superimposed along the height direction. Step by step forming three-dimensional entity. At present, the rapid prototyping system of FDM process can only read the STL format file in the market, and the STL format file is the approximate expression of the CAD model, that is, a series of triangular plane slices are used to approximate represent the CAD model data file. There is geometric distortion of the part itself. The two-dimensional laminates based on this scheme are polygonal contours connected by straight lines, which make the information of the model layers also have geometric distortion. As a result, the surface accuracy of rapid prototyping parts is poor. At present, parallel straight lines are used in the filling of sections. For thin-walled cross-sections, the filling path is serrated, and there is discontinuity and non-uniformity. The forming parts have the problems of uneven wall thickness and poor physical properties. In order to solve the problem of geometric distortion caused by stratification based on STL model, this paper proposes a direct delamination of CAD model, and realizes the direct delamination in software by AutoCAD secondary development tool. The two-dimensional contour of the resulting layer is a smooth curve. In order to ensure the precision of the forming parts, aiming at the problem of filling trajectory in the section of thin-walled parts with uniform wall thickness, this paper puts forward two methods of mixed filling in Z direction, that is, the odd layer is filled with parallel straight lines. The even layer is filled with contour trajectory bias line, and the software is developed on Visual C 6.0 platform through AutoCAD2002 secondary development tool ObjectARX2002. The software can be used to simulate the two trajectories in AutoCAD2002. This method not only alleviates a series of disadvantages brought by parallel line filling, but also improves the efficiency of rapid prototyping to a great extent. Under the condition of no increasing the cost, the forming efficiency, the precision and the performance of the molded parts are improved, which provides the feasibility for the next step to extend to the rapid prototyping equipment.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH164

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