金属激光直接沉积增材制造工艺研究

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题名	金属激光直接沉积增材制造工艺研究
作者	来佑彬
学位类别	博士
答辩日期	2015-05-27
授予单位	中国科学院沈阳自动化研究所
授予地点	中国科学院沈阳自动化研究所
导师	刘伟军 ; 赵吉宾
关键词	激光直接沉积增材制造田口方法工艺参数优化残余应力
其他题名	Research on Processing Characteristics during Laser Metal Direct Desposition Additive Manufacturing
学位专业	机械电子工程
中文摘要	金属激光直接沉积增材制造是在上世纪八十年代末期兴起的激光熔覆技术的基础上开发出来的一种先进制造技术，该技术利用高能量的激光束将同步送入的金属粉末熔化并直接沉积在基板上形成熔覆点，基板与激光束在运动执行机构的作用下能够产生相对运动，从而使熔覆点成为熔覆线，线与线之间搭接就形成熔覆面，最终面与面之间的堆积得到三维立体零件。该技术创造性地将激光技术、材料科学、数控加工以及CAD/CAM技术等相关领域关键技术结合在了一起。金属激光直接沉积增材制造技术虽然已经被提出多年，却没能像其他传统制造技术那样被广泛应用，这其中一方面的原因是其工艺水平上不去，限制了该技术的发展；另一方面，金属激光直接沉积增材制造中的变形开裂问题始终是制约该技术广泛应用的瓶颈，而残余应力又是导致增材制造零件变形开裂的罪魁祸首。因此，本文的主要工作就是对金属激光直接沉积增材制造技术的工艺进行深入而系统的研究，并对增材制造中的残余应力影响因素以及调控措施进行深入分析，以期为该技术的长远发展和普及应用添砖加瓦，具体的研究内容如下： 1. 介绍本文的研究背景与意义并对金属激光直接沉积增材制造技术的原理、优点与不足进行分析。综合阐述国内外金属激光直接沉积增材制造技术的研究进展，给出本文的主要研究内容和技术路线。 2. 针对金属激光直接沉积增材制造系统的特点，借助模糊评价方法自主设计、开发出用于金属激光直接沉积增材制造的系统。该系统结构完整、功能完善、可靠性高，能够满足多种材料复杂结构金属零件的增材制造，并且最大化的节约了成本。 3. 将金属激光直接沉积增材制造基础工艺系统性地分为单道单层成形工艺、多道单层搭接成形工艺、单道多层堆积成形工艺、单道多层偏移堆积成形工艺、单道多层扭转堆积成形工艺、多道多层搭接堆积成形工艺等六大门类，主要研究了激光功率、送粉速度等基础工艺参数对增材制造精度和质量的影响情况。 4. 对基于田口方法的单目标工艺参数优化方法和基于灰系田口方法的多目标工艺参数优化方法进行了详细地研究，并对多道单层增材制造中的表面平整度和宽度误差两个目标问题进行了工艺参数优化分析，并得到同时满足二者最优的参数组合。 5. 对金属激光直接沉积增材制造残余应力形成机理进行了研究，结合金属激光直接沉积增材制造残余应力的实际测试需求和工艺特点，提出了一种新的可测量三维残余应力的方法。 6. 金属激光直接沉积增材制造中残余应力调整与控制的研究具有十分重要的意义。本文将金属激光直接沉积增材制造残余应力的调控措施分为增材制造之前调控措施、增材制造之中调控措施和增材制造之后调控措施。 7. 通过简单有效地测量方法对金属激光直接沉积增材制造零件及基板残余应力的影响因素进行了研究，为金属激光直接沉积增材制造残余应力的控制提供了理论基础。
索取号	TG665/L12/2015
英文摘要	Laser metal direct deposition additive manufacturing is an advanced manufacturing technology developed on the basis of laser cladding technology emerged in the late 1980s. It uses high-energy laser beam to melt the synchronized metal powder, and the melted metal powder deposits directly on the substrate to form cladding point. The substrate generates relative movement with the laser beam under the effect of the actuator movement, so that the cladding points become cladding wire. The cladding wires overlap to form cladding surface. The cladding surfaces heap up to obtain three-dimensional parts finally. The technology combines the key technologies of laser technology, materials science, CNC machining, CAD / CAM technology and other related areas. Laser metal direct deposition additive manufacturing has been proposed for many years, but it is not as widely used as other traditional manufacturing techniques. The great reason is the process level limiting the development of this technology. The main work of this thesis is an in-depth and systematic research on the process of laser metal direct deposition additive manufacturing. And the residual stress influence factors in laser metal direct deposition additive manufacturing and its control measures were analyzed. The specific contents are as follows: 1. The background and the significance of this thesis was introduced. Meanwhile, the laser metal direct deposition additive manufacturing theory and characteristics were analyzed. After comprehensively elaborating the research progress of this technology, the main research content and technical route of this thesis was proposed. 2. According to the laser metal direct deposition additive manufacturing characteristics, a hardware system for this technology was designed and developed independently by means of fuzzy evaluation method. The system has a series of advantages including structural integrity, perfect function, high reliability. It can meet the need of multiplex materials and complex structure metal parts deposition manufacturing technology. Furthermore, it saves the costs markedly. 3. The laser metal direct deposition additive manufacturing basis process was systematically divided into single-track multi-layer forming process, multi-track single-layer overlapped forming process, single-track multi-layer stacked forming process, single-track multi-layer offset stacked forming process, single-track multi-layer offset torsion forming process, multi-track multi-layer overlapped stacked forming process. The main research was the influence of process parameters including laser power, powder feeding rate, scanning speed, overlap rate, direction Z increment, scanning method on forming parts quality. In addition, the cumulative effect of the energy was studied. 4. The single objective parameter optimization method based on Taguchi method and multi-objective optimization method based on gray system Taguchi method were studied in detail. The two target parameter optimization problems of surface roughness and width of deviation in the multi-track single-layer forming progress were analyzed. Both at the same time, the optimal parameters combination was obtained. 5. The residual stress formation theory in the laser metal direct deposition additive manufacturing was researched. According to the test requirements and process characteristic of residual stress in laser metal direct deposition additive manufacturing, a new method of measuring residual stress in the three-dimensional depth direction was proposed. 6. The research on residual stress adjustment and control in laser metal direct deposition additive manufacturing was of great significance. The residual stress control measures in laser metal direct deposition additive manufacturing were divided into control measures before it, control measures among it and control measures after it. 7. The laser metal direct deposition additive manufacturing parts and substrate residual stress influence factors were investigated by a simple and effective method. It provides a theoretical basis of residual stress control in laser metal direct deposition additive manufacturing.
语种	中文
产权排序	1
页码	133页
内容类型	学位论文
源URL	[http://ir.sia.ac.cn/handle/173321/16765]
专题	沈阳自动化研究所_装备制造技术研究室
推荐引用方式 GB/T 7714	来佑彬. 金属激光直接沉积增材制造工艺研究[D]. 中国科学院沈阳自动化研究所. 中国科学院沈阳自动化研究所. 2015.