水轮机模型叶片CMT增材制造工艺及轨迹规划研究

发布时间：2019-02-08 20:32

【摘要】：电弧增材制造(Additive manufacturing)技术,通过电弧熔化金属焊丝,并根据事先或者在线生成的轨迹与焊枪姿态完成金属零件的成形工作。目前电弧增材制造的各种文献与相关报道大多针对工艺参数,以及力学性能与组织分析进行研究,对于如何使用合适的轨迹成形特定的工件同时保证工件倾斜时熔池不下塌、保证尺寸精度等方面研究较少。本文以保证成形精度为目的,研究了不同焊接速度、焊接电流下的焊缝尺寸特征,研究了大倾斜角度墙体的轨迹规划问题,同时设计了基于SolidWorks二次开发的轨迹规划算法与基于MATLAB的后处理程序,并以此为软件系统搭建了CMT电弧增材制造系统。使用离线控制,对水轮机模型叶片进行了成形作业,对系统的稳定性、轨迹规划的正确性进行了验证。研究了有、无预热下,焊接电流、焊接速度与余高熔宽的匹配关系,为后续实验提供数据支持。对比已有轨迹规划引擎,找到适合金属增材制造的三轴轨迹规划方法,并结合该方法对扭转墙体、倾斜柱体进行了成形。结果发现三轴轨迹不能满足以上模型的精度要求,通过进一步实验确定平行面切片、平行线扫描与五轴轨迹规划能够满足倾斜工件的精度要求。系统地对使用SolidWorks二次开发的轨迹规划进行了研究,设计了针对电弧尺寸量级的五轴轨迹规划程序,深入研究了复杂形状的平行扫描算法以保证最少的起弧熄弧数,研究了焊枪倾斜算法,以重点解决倾斜工件的下塌问题。使用MATLAB开发了后处理程序,以驱动YASKAWA机器人、调节焊接参数与机器人姿态。搭建了CMT增材制造系统,将其用在实际的水轮机模型叶片成形作业中。针对具体工程问题进行了相关准备工作,使用本文叙述的轨迹规划方法进行成形,根据已焊焊缝高度,以不同焊接电流与焊接速度下熔宽余高为数据支撑,反馈调节下一层焊接速度与焊接电流,以保证成形精度。成形过程稳定,成形结果留有加工余量,尺寸精度高。
[Abstract]:The (Additive manufacturing) technology of arc augmentation is used to melt the metal wire, and the metal parts are formed according to the trajectory generated in advance or online and the position of the welding torch. At present, most of the literatures and related reports on the manufacture of arc material are focused on the process parameters, mechanical properties and microstructure analysis. How to use the appropriate trajectory to shape the specific workpiece while ensuring that the molten pool does not collapse when the workpiece is tilted. The research on ensuring dimensional accuracy is less. In order to ensure the forming accuracy, this paper studies the weld seam size characteristics under different welding speed and welding current, and studies the trajectory planning of the wall with large inclined angle. At the same time, the trajectory planning algorithm based on SolidWorks and the post-processing program based on MATLAB are designed, and the CMT arc material augmentation manufacturing system is built for the software system. Off-line control is used to form the turbine model blade. The stability of the system and the correctness of the trajectory planning are verified. The matching relationship between welding current, welding speed and residual width without preheating is studied, which provides data support for subsequent experiments. Comparing with the existing trajectory planning engine, a three-axis trajectory planning method suitable for metal material augmentation is found, and the torsional wall and inclined cylinder are formed with this method. The results show that the triaxial trajectory can not meet the precision requirements of the above model. Through further experiments, the parallel plane slice, parallel line scanning and five-axis trajectory planning can meet the accuracy requirements of the tilted workpiece. The trajectory planning developed by SolidWorks is studied systematically. A five-axis trajectory planning program for arc size is designed, and the parallel scanning algorithm with complex shapes is deeply studied to ensure the minimum number of arc-extinguishing arcs. The welding torch tilting algorithm is studied in order to solve the problem of sloping workpiece. A post-processing program is developed with MATLAB to drive YASKAWA robot and adjust welding parameters and robot posture. The CMT material increasing manufacturing system is built and used in the actual blade forming of hydraulic turbine model. According to the height of welded seam, the residual height of weld width at different welding current and speed is used as data support. Feedback adjustment of the next layer of welding speed and welding current to ensure the forming accuracy. The forming process is stable, the forming result has the machining allowance, the dimension precision is high.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG44

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