基于激光再制造的三维同轴送粉工作头研究

【作者】 刘运武；

【导师】 杨洗陈； 王云山；

【作者基本信息】 天津工业大学 ， 机械设计及理论， 2004， 硕士

【摘要】 激光再制造是一种以激光熔覆技术为核心的新兴绿色修复技术。它可以实现对重大零件的快速修复，降低成本，为企业参与市场竞争赢得时间。同轴送粉工作头是激光再制造系统的关键部件，涉及激光与材料相互作用许多基本问题，深入开展三维同轴送粉工作头的研究具有重要的理论意义和应用价值。 本文介绍了激光再制造技术的原理，综述了国内外研究发展现状。建立了粒子受热状态、光能分配模型和粉末流场浓度模型，对光粉相互作用进行了较深入的理论分析。综合机械设计的相关理论，设计出具有三维空间工作功能、粉末流束焦点可调的新型送粉工作头。首次结合数字粒子图像测速技术(DPIV)设计了对粉末流束的速度场和浓度场的试验方案，并实际检测了在不同工作状态下的粉末流束的速度场和浓度场。开展了送粉工作头的实际应用试验研究，利用研制的三维送粉工作头对导套零件和不锈钢板进行了大面积激光再制造的初步试验研究，取得了良好的效果。分析了工艺参数对粉末利用率、熔覆层质量等方面的影响。 试验表明同轴送粉工作头具有全方向性和和其粉末流束的焦点可调节特性。其主要技术参数如下： 聚焦方式： 透镜／反射聚焦 送粉方式： 载气式／非载气式 Φ轴转角： 0°—360° Ψ轴转角： -60°—+60° 粉末利用率： 载气式≥30％，非载气式≥60％更多还原

【Abstract】 Laser refabrication is a kind of new green reconstruction technology that based on laser cladding. It can be used to repair important weared parts rapidly, so it may bring the reducing production cost and saving working time. 3D coaxial feeding head is the most important and key part in laser refabrication. Many problems of interactions between laser and materials were involved in. It is significant and valuable to carry through the research of 3D coaxial feeding head deeply.In this paper, technical principles of laser refabrication were introduced. Current states of development were summarized in China and other countries. Model of the heated particles, model of division of the laser energy and concentration of powder stream were presented. Interaction between powder particles and laser was analyzed deeply. New 3D coaxial feeding head with adjustable of the powder stream focus was designed. DPIV(Digital Particle Image Velocimetry) technology was used to observe velocity fields and concentration fields of powder streams. A series of processing tests using 3D coaxial feeding head were carried out. Using 3D coaxial feeding head, large area laser refabrication was carried out in metallic sheath and stainless steel plates. The influence of the technological parameters to powder utilization ratio and quality of cladding were analyzed.It is shown that the 3D coaxial feeding head has the characteristic of full-direction and adjustable focus of powder stream.Major technical parameters of 3D coaxial feeding head: Focus model: lens focus/reflection focusFeeding model: carrying gas/without gasRotational angle of Φ axis: 0° -360°Rotational angle of ψ axis: -60 °--+60°Powder utilization ratio: feeding with carry gas >30%feeding without gas >60%更多还原