基于FDM成型技术的3D打印工件机械性能及质量研究分析

发布时间：2018-11-24 08:52

【摘要】：3D打印快速成型技术是制造业领域正在迅速发展壮大的一项新兴的增材制造技术,被喻为具有工业革命意义的制造技术。3D打印凭借其独特的优势,正在逐渐席卷全球。到目前为止,人类已经利用3D打印技术成功制造出了很多产品。然而3D打印成型的工件质量还存在很大的问题及缺陷,例如零件的力学性能不足以满足实际应用等。本课题旨在研究通过改进基于FDM成型技术的3D打印工艺提高工件的机械性能以及成型质量。本课题具体的工作内容及结论如下:(1)分别就打印温度、填充率、轮廓圈数、层厚、填充角度以及填充方式六个工艺参数对PLA和PA B330两种材料的力学性能进行分析,分析每个参数的变化对样条力学性能的影响效果,得出每个参数最佳的打印参数取值。(2)对PLA和PA B330两种材料在打印温度、填充率、轮廓圈数、层厚、填充角度以及填充方式六个工艺参数下进行了详细的比较,对每一个参数都详细对比了两种材料之间的异同,并分析产生这种差异的内在原因。研究表明:打印温度越高,PLA和PA B330的极限强度越大,而PLA的弹性模量越小,PA B330的弹性模量越大。轮廓圈数越多,PLA和PA B330的极限强度和弹性模量均越大,但是断裂伸长率越小。层厚越大,PA B330的极限强度越小而弹性模量越大,对PLA力学性能的影响不明显。填充率对两种材料的性能影响非常大,填充率越高,两种材料的极限强度和弹性模量越大。填充角度从0°到45°时,PA B330极限强度越来越大而弹性模量越来越小。直线填充和蜂窝填充对PLA和PA B330的影响恰恰相反。(3)建立数学模型并计算理论结果。根据一定的假设条件对样条建立抽象的数学模型,将样条分割为一个个的元素,对于每一个元素分成四个部分,分别计算每一部分的力以及相邻丝径之间的粘结力,最终计算出样条的极限强度和弹性模量。(4)试验结果与理论分析对比。以轮廓圈数和填充率这两个工艺参数为例,对不同的轮廓圈数计算其极限强度和弹性模量,分别与实验结果进行比较。对比分析表明该理论模型能够较好地模拟样条弹性变形阶段过程。同时对于不同的填充率计算其样条横截面中材料覆盖面积,得出了填充率越高,相邻丝径之间的粘结力越大的结论。
[Abstract]:3D printing rapid prototyping is a new material increasing manufacturing technology which is developing rapidly in the field of manufacturing, and it is regarded as the manufacturing technology with the significance of industrial revolution. 3D printing is sweeping the whole world with its unique advantages. Up to now, many products have been produced successfully by using 3D printing technology. However, there are still many problems and defects in the quality of 3D printing workpiece, for example, the mechanical properties of the parts are not enough to meet the practical application and so on. The purpose of this paper is to improve the mechanical properties and molding quality of workpieces by improving the 3D printing process based on FDM technology. The specific contents and conclusions of this paper are as follows: (1) the mechanical properties of PLA and PA B330 are analyzed in terms of printing temperature, filling ratio, contour circle number, layer thickness, filling angle and filling mode. The effect of the change of each parameter on the mechanical properties of spline is analyzed, and the optimum print parameter value of each parameter is obtained. (2) for PLA and PA B330, the printing temperature, filling ratio, number of contour circles, thickness of layer are obtained. The filling angle and filling mode are compared in detail under six technological parameters. The similarities and differences between the two materials are compared in detail for each parameter, and the internal reasons for the difference are analyzed. The results show that the higher the printing temperature, the greater the ultimate strength of PLA and PA B330, while the smaller the elastic modulus of PLA is, the greater the elastic modulus of PA B330 is. The higher the number of contour circles, the greater the ultimate strength and elastic modulus of PLA and PA B330, but the smaller the elongation at break. The greater the thickness of the layer, the smaller the ultimate strength and the greater the elastic modulus of PA B330, and the less the effect on the mechanical properties of PLA. The filling ratio has a great influence on the properties of the two materials. The higher the filling ratio is, the greater the ultimate strength and elastic modulus of the two materials are. When the filling angle is from 0 掳to 45 掳, the ultimate strength and elastic modulus of PA B330 become larger and smaller. The effect of linear packing and honeycomb filling on PLA and PA B330 is opposite. (3) the mathematical model is established and the theoretical results are calculated. The abstract mathematical model of spline is established according to certain assumptions, and the spline is divided into one element. For each element, the force of each part and the adhesion between adjacent wire diameters are calculated respectively for each element divided into four parts. Finally, the ultimate strength and elastic modulus of the spline are calculated. (4) the experimental results are compared with the theoretical analysis. The limit strength and elastic modulus of different contour cycles are calculated by taking the two technological parameters of contour cycle number and filling ratio as examples. The results are compared with the experimental results. The comparative analysis shows that the theoretical model can well simulate the elastic deformation process of spline. At the same time, for the different filling ratio, the material covering area in the spline cross-section is calculated, and it is concluded that the higher the filling ratio is, the greater the adhesion between the adjacent wire diameters is.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH164

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