【作者】 朱萍；

【导师】 石世宏；

【作者基本信息】 苏州大学 ， 机械制造及其自动化， 2013， 硕士

【摘要】 激光熔覆技术是先进制造技术的一个重要研究方向，在一些金属部件的制造中也得到了广泛应用，然而激光熔覆快速成形特别是同轴送丝成形的发展较慢。由于激光熔覆快速成形件质量与送丝激光熔覆层的几何冶金特征关系密切。因此建立同轴送丝激光熔覆层几何特征的数学模型非常必要。本文主要针对光内同轴送丝激光熔覆层几何特征进行研究。分析同轴送丝激光熔覆过程中的能量转化和环形激光束的能量分布，在此基础上分析激光与金属丝材的相互作用，根据能量守恒和能量平衡关系建立熔覆层横截面的数学模型。假设熔覆层横截面轮廓为圆弧状，建立熔覆层横截面几何特征与熔覆工艺参数（激光功率、扫描速度、送丝速度）之间的数学模型，同时建立了熔覆层宽度关于熔覆工艺参数的回归数学模型。通过对熔覆层几何特征的数学模型进行仿真，分析各工艺参数对其的影响后发现熔覆层宽度受激光功率的影响最大，并随着激光功率的增大而增大；熔覆层高度起初随扫描速度的增大而增大，当达到一定扫描速度时，又随扫描速度的增大而减小；同样激光功率对熔覆层高度影响较大；熔覆层高度与激光功率和送丝速度大小呈正比，与扫描速度呈反比；送丝速度对熔覆层高度的影响甚微。将试验结果与建模预测值进行了对比分析，发现熔覆层几何特征的模拟值与试验值之间的误差较小，并且实际检测的参数值与理论计算的数据反映了相同的规律性。可以证明该模型的可靠性。基于熔覆层几何特征关于工艺参数的数学模型建立，进行了薄壁墙的堆积。通过对模型的计算，选择了最优的参数进行首层堆积，多层堆积时通过测出每层熔池的温度，运用模型计算出此层所需的激光功率。为保证每层层高的一致，本课题组选用了CCD在线监测系统，保证了壁厚的均匀性和形貌的光滑完整。体现了本模型的可行性。更多还原

【Abstract】 As one of the research direction of the advanced manufacturing technology, laser cladding has been applied in some metal parts manufacturing. However, the development of laser cladding rapid prototyping is slowly. Because of the quality of forming parts which made by laser cladding rapid prototyping technology is close related to the geometrical characteristics of laser cladding layer. So it’s necessary to build a mathematic model of the geometric feature of cladding layer.It’s mainly aimed at study the cladding layer’s geometric feature of coaxial inside-beam laser cladding by wire. By analyzing the energy conversion and energy distribution of laser beam in a circle in the cladding process. Based on the above, analyse the interaction between laser and metal wire, then according to the onservation of energy and balance the relationship set up the mathematic model of the cladding layer cross sectional area. Assume that the cladding layer of cross section contour is arc shape, building the mathematical model which related to geometry characteristics of cladding layer cross section and the cladding process parameters (laser power, scanning velocity and wire feed speed). And width model of the cladding layer about the cladding process parameters was established by regression mathematical model.Through simulating the mathematical model of the geometric feature of the cladding layer and analyzing the influence of various process parameters on the cladding layer Consider that laser power has the biggest influence on cladding layer width and increases with the increase of laser power. Cladding layer height increases with the increase of scanning speed, when reach certain scanning velocity, however, decreases with the increase of scanning speed. Also laser power had a greater influence on the cladding layer height, and cladding layer height is proportional to the laser power and the speed of wire feeding, and is inversely proportional to the scanning speed. Wire feeding speed has little effect on cladding layer height. Contrast the predicted value with experimental results, found that the error is minor, and reflects the same regularity. So it’s enough to prove the reliability of the model.Based on the model about cladding layer geometric feature. Through calculation of the model, select the optimal parameters of the first layer. With the model to calculated the require power of this layer through measured the temperature of the molten pool. In order to ensure the consistent of each layer height, choosing the CCD online monitoring system. Then single beads wall is accumulated, ensure the uniformity of wall thickness and smooth and full of the shape. To further illustrate the feasibility of the model.更多还原