面曝光快速成形技术的变形研究

发布时间：2018-05-08 03:36

本文选题：快速成形 + 仿真模拟　；参考：《西安工程大学》2012年硕士论文

【摘要】：随着现代工业技术的发展和计算机应用水平的提高，微型机械的发展取得了很大的突破，，它是一个集合了机械技术和计算机技术的综合性学科。微型机械具有效率高、体积小、耗能少、性能高等突出的优点，并因此广泛应用于各个工业领域中，具有广阔的发展前景。目前，面向微小结构制作的光固化快速成形技术在世界范围内已成了研究和开发的热点。面曝光快速成形技术作为光固化快速成形技术中的一种，是微型机械制造领域中应用较为广泛的新型光固化技术。变形问题是光固化快速成形技术（SL）中必然存在的问题，也是一个急需解决的难题。变形问题严重制约了光固化快速成形技术（SL）的发展，不仅影响了零件的精度、外观质量、装配以及使用性能，而且使成形过程难以控制，甚至使零件制作失败，所以要尽量避免变形的发生。为了更好的满足客户的需求，减小变形，提高成形零件的制作精度，本文对于面曝光快速成形技术中的变形问题做了系统的研究。首先，文中论述了面曝光快速成形技术中层层累积的成形原理，从理论上对面曝光快速成形技术的变形机理进行了研究，并详细分析了收缩中心理论和收缩应力。在对面曝光快速成形技术中的变形机理进行理论分析的基础上，建立了用于理论分析的数学模型，构建了小挠度温度应力弯曲微分方程，得出变形（挠度g）与层数n、温差T和位置尺寸x和y等参数间的定量关系式。另外，使用MATLAB软件拟合了挠度方程g（x，y）的数学模型。其次，结合面曝光快速成形系统的制作条件，使用ANSYS仿真软件中“生死单元”的方法模拟了零件曝光固化后的收缩变形情况。在模拟过程中，通过软件的前处理（PREP7）、求解（Solution）和后处理（POST1、POST26）阶段对变形进行仿真模拟，获得了一系列模拟数据。利用Excel处理模拟数据，拟合出各个变形影响因素与变形量之间的关系曲线。使用控制变量法对变形与主要影响因素之间的关系进行了分析研究，发现层数越多，产生的变形越少，变形主要发生在最初的若干层。另外，温差越小，离收缩中心越近，产生的变形越小。然后，对面曝光快速成形零件的变形进行了大量的实验研究，得出不同条件下制作零件的变形数据。利用实验数据研究了面曝光快速成形零件的变形与主要影响因素之间的关系，验证了理论分析和软件模拟的正确性，阐述了产生变形的原因。根据以上研究结论，提出了减小零件变形的一系列措施如设置支撑、选择合适的工艺参数等，为减小零件的变形，提高成形零件的制作精度提供了依据。最后，为了更有效的减小零件的变形，论文还研究了分区域曝光和交错曝光两种新型曝光模式。这两种曝光模式是指同一固化层首先被分割成多个区域，从而曝光面积有所减小，然后在不同的时间段内，分别对这些区域进行曝光固化。每个单独的固化区域可以进行自由的收缩变形，内部应力有足够的时间释放，最后形成整个树脂固化层，且其变形减小。理论分析及实验结果表明这两种曝光模式能减小成形零件的变形。以上研究，对减小面曝光快速成形零件的变形，提高制作精度具有十分重要的意义。
[Abstract]:With the development of modern industrial technology and the improvement of computer application level , the development of micro machinery has made great breakthrough . It is a comprehensive subject of mechanical technology and computer technology . It has the advantages of high efficiency , small volume , low energy consumption , high performance and so on .

The deformation problem is the inevitable problem in the rapid prototyping technology ( SL ) , and it is an urgent problem . The deformation problem seriously restricts the development of light curing rapid prototyping technology ( SL ) , which not only affects the precision , the appearance quality , the assembly and the use performance of the parts , but also makes the forming process difficult to control and even makes the part manufacture fail . In order to better meet the needs of the customer , reduce the deformation and improve the manufacturing precision of the forming part , the paper studies the deformation problem in the surface exposure rapid prototyping technology .

Firstly , the forming principle of layer - by - layer accumulation in the surface exposure rapid prototyping technology is discussed , the deformation mechanism of the rapid prototyping technology is studied theoretically , and the shrinkage center theory and the shrinkage stress are analyzed in detail . Based on the theoretical analysis of the deformation mechanism in the opposite exposure rapid prototyping technology , a mathematical model for the theoretical analysis is established , and a quantitative relation between the deformation ( deflection g ) and the parameters such as the number n , the temperature difference T and the position dimension x and y is obtained . In addition , the mathematical model of the deflection equation g ( x , y ) is fitted by MATLAB software .

In the simulation process , the relationship between the deformation and the deformation is simulated by means of pre - processing ( PREP7 ) , solution and post - processing ( POST1 , POST 26 ) . The relationship between the deformation and the deformation is simulated by using the control variable method .

Then , a large number of experiments are carried out on the deformation of the fast forming part opposite to the exposure , and the deformation data of the parts are produced under different conditions . The experimental data is used to study the relationship between the deformation and the main influencing factors of the surface exposure fast forming part . The reason of the deformation is verified . According to the above research conclusion , a series of measures for reducing the deformation of the part are put forward , such as setting up support , selecting suitable process parameters , etc . , and providing a basis for reducing the deformation of the part and improving the manufacturing accuracy of the forming part .

In the end , in order to reduce the deformation of the parts more effectively , the paper also studies the two types of exposure modes of sub - region exposure and staggered exposure . The two exposure modes refer to the fact that the same curing layer is first divided into a plurality of regions , so that the exposure area is reduced , and then the regions are exposed and cured respectively in different time periods .

In the above research , it is very important to reduce the deformation of the surface - exposed quick - forming part and improve the precision of manufacturing .

【学位授予单位】：西安工程大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH16;TG665

【参考文献】