金属粉末SLS打印机结构改进设计与成型质量研究

发布时间：2019-04-24 00:47

【摘要】：选择性激光烧结(SLS)打印技术是一种先进的快速制造技术,国内外对金属粉末SLS打印技术进行了研究,但国内相关研究相比国外还有一定差距。本课题对金属SLS打印机结构以及成型质量影响因素进行了研究。以改进打印机结构、提高成型件质量为目标展开课题研究。对打印机总体结构进行设计,针对现有铺粉装置无法克服烧结过程中金属粉末“球化飞溅”带来的影响,对铺粉装置进行改进,在铺粉辊表面增加一层硬质橡胶并在铺粉辊前设置一个一定厚度的刮板。加工零件,组装出实物样机,分别使用改进前和改进后的铺粉装置在实物样机上进行测试,结果表明改进后的装置可缓解球化飞溅现象,对成型质量有提升作用。对测试样件进行尺寸精度分析,实际尺寸与理论尺寸存在一定偏差,需要对成型质量影响因素进行研究以便进一步提升成型质量。分析几何数据处理、粉末材料性质、成型工艺参数以及扫描方式对成型质量的影响,对各参数的选取提出建议。研究成型质量的评价问题,针对目前没有能够全面系统反映出成型件整体质量的测试件的现象,设计一种能够较全面评价成型件整体成型质量的测试件,对制定合理的成型质量评价模型有一定参考作用,为全面系统地评价成型质量奠定基础。针对国内外对金属粉末三维烧结温度场研究较少的现状,以水雾化铁粉作为研究对象,对金属粉末的连续移动三维瞬态温度场进行数值模拟,对结果进行分析,有利于掌握烧结过程中温度场的动态分布情况,通过改变烧结参数分析影响成型质量的工艺因素,对实际的试验做出理论指导并提供理论依据。综上所述,本课题的开展为金属SLS打印技术进一步研究奠定了一定理论与技术基础。
[Abstract]:Selective laser sintering (SLS) (SLS) printing technology is an advanced rapid manufacturing technology. The metal powder SLS printing technology has been studied at home and abroad, but there is still a certain gap between domestic and foreign related research. In this paper, the structure of metal SLS printer and the influencing factors of forming quality are studied. In order to improve the printer structure, improve the quality of forming parts as the goal of the research. The overall structure of the printer is designed. In view of the fact that the existing powder laying device can not overcome the influence of "spheroidization spatter" of metal powder in the sintering process, the powder laying device is improved. Add a layer of hard rubber to the surface of the roller and set a thickness scraper in front of the roll. The parts are processed, the prototype is assembled, and the powder laying device is tested on the prototype before and after the improvement. The results show that the improved device can alleviate the spatter phenomenon of spheroidization and improve the molding quality. The dimension precision analysis of the test sample shows that there is a certain deviation between the actual size and the theoretical dimension, so it is necessary to study the influencing factors of the forming quality in order to further improve the forming quality. The influences of geometric data processing, properties of powder materials, forming process parameters and scanning mode on forming quality are analyzed, and some suggestions are put forward for the selection of each parameter. The evaluation of forming quality is studied. Aiming at the phenomenon that there is no comprehensive and systematic test part which can reflect the whole quality of forming part at present, a kind of testing piece which can evaluate the whole forming quality of forming part is designed, which can be used to evaluate the whole forming quality of forming part in a more comprehensive way. It can be used as a reference to establish a reasonable molding quality evaluation model and lay a foundation for the overall and systematic evaluation of molding quality. In view of the lack of research on three-dimensional sintering temperature field of metal powder at home and abroad, the three-dimensional transient temperature field of continuous movement of metal powder is numerically simulated and the results are analyzed by using water-fogged iron powder as the research object. It is beneficial to grasp the dynamic distribution of the temperature field in the sintering process. By changing the sintering parameters, the technological factors affecting the forming quality are analyzed, and the theoretical guidance and theoretical basis are provided for the practical test. In summary, the development of this topic for the further study of metal SLS printing technology laid a certain theoretical and technical basis.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TF37

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