激光选区熔化成型可控超轻结构化零件的孔隙生成效果

发布时间：2018-10-26 08:42

【摘要】：本文主要研究了孔隙率等参数可控的自动超轻结构化金属零件的增材制造。以方块零件及一个具有复杂外形的零件为研究对象,分析了面向激光选区熔化工艺的可控超轻结构化零件的孔隙生成效果,重点探讨了成型工艺对超轻结构化零件孔隙率的影响。结果显示:通过计算机数值计算,可将方块CAD模型快速自动转化为可控超轻结构化模型,计算孔隙率误差可控制在±2%以内;激光深穿透现象会导致带悬垂面内壁的壁厚增加,所引起的孔隙率误差值为负值,且计算孔隙率越大,负值倾向越严重;而成型工艺性不致密导致的孔隙率误差为正值,且在相同工艺条件下,计算孔隙率越大,该误差值越小。故为使总孔隙率误差能较好地反映超轻结构网格孔隙的控制精度,应提高成型时实体部分的致密性。按45%设定孔隙率成功地将具有复杂结构的零件转化为计算孔隙率为44.62%的超轻结构化模型,采用高致密性激光选区熔化工艺成型后,实测孔隙率为42.94%,无悬垂面的内壁壁厚误差≤0.06mm,达到了较好的超轻结构控制效果。
[Abstract]:In this paper, the fabrication of automatic ultra-light structured metal parts with controllable porosity and other parameters is studied. Taking the block parts and a part with complex shape as the research object, the pore generation effect of the controllable ultra-light structured parts for the laser selective melting process is analyzed. The effect of molding process on the porosity of ultra-light structured parts is discussed. The results show that the block CAD model can be quickly and automatically transformed into a controllable ultra-light structured model by computer numerical calculation, and the calculated porosity error can be controlled within 卤2%. The deep penetration of laser will lead to the increase of the wall thickness of the inner wall with hanging plane, and the difference of porosity is negative, and the larger the calculated porosity is, the more the negative tendency is. However, the porosity error caused by non-compactness of molding process is positive, and the larger the calculated porosity is, the smaller the error is under the same process conditions. Therefore, in order to make the total porosity error better reflect the control accuracy of ultra-light structure meshes, it is necessary to improve the compactness of solid parts during forming. According to the established porosity of 45%, the parts with complex structure were successfully converted into an ultra-light structured model with a calculated porosity of 44.62%. The measured porosity was 42.9442.94after the high density laser selective melting process was adopted. The thickness error of the inner wall is less than 0.06mm without the hanging surface, and the control effect of the ultra-light structure is better.
【作者单位】：韶关学院物理与机电工程学院;华南理工大学机械与汽车工程学院;湖南科技大学先进矿山装备教育部工程研究中心;
【基金】：国家自然科学基金(No.51405156) 广东省高等学校优秀青年教师培养计划资助项目(No.Yq2013149) 广东高校优秀青年创新人才培养计划项目(No.2013LYM_0083)
【分类号】：TG665

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