| 引用本文: | 杨高林,朱兆恒,李梓杉,李贺杰,吴国龙,张群莉,王梁,姚建华.分区尺寸对选区激光熔化成形316L表面结构的影响*[J].中国表面工程,2023,36(3):74~86 |
| YANG Gaolin,ZHU Zhaoheng,LI Zishan,LI Hejie,WU Guolong,ZHANG Qunli,WANG Liang,YAO Jianhua.Influence of Divisional Size on Structural Quality of 316L Parts Printed by Selective Laser Melting[J].China Surface Engineering,2023,36(3):74~86 |
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| 分区尺寸对选区激光熔化成形316L表面结构的影响* |
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杨高林1,2,3, 朱兆恒1,2,3, 李梓杉1,2,3, 李贺杰1,2,3, 吴国龙1,2,3, 张群莉1,2,3, 王梁1,2,3, 姚建华1,2,3
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1.浙江工业大学机械工程学院 杭州 310023;2.浙江工业大学高端激光制造装备省部共建协同创新中心 杭州 310023;3.浙江工业大学激光先进制造研究院 杭州 310023
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| 摘要: |
| 分区扫描策略对选区激光熔化成形件的表面质量有重要影响，而目前分区尺寸对成形件表面结构的影响规律尚不清晰。 为进一步提高选区激光熔化成形带支撑悬垂结构的表面质量及尺寸精度，以带支撑方形悬垂结构为研究对象，结合数值模拟与成形试验从表面原始轮廓的形状误差、波纹度与表面粗糙度三个不同波距的表面结构进行研究。研究结果表明：随着分区尺寸的减小，成形件表面边缘的翘曲高度逐渐降低，但相邻分区之间的轮廓起伏程度逐渐增加，成形件截面轮廓的形状误差与表面粗糙度得到改善，波纹度呈现出增大趋势，使成形表面形貌呈先改善后降低趋势。形状误差、波纹度与表面粗糙度随分区尺寸的减小变化趋势并不一致，分区尺寸过小会导致热累积现象明显，波纹度增加。在减小分区尺寸的同时适当降低激光能量输入，能有效改善表面形貌。为提高 SLM 成形带支撑悬垂结构的尺寸精度和表面形貌提供了理论基础。 |
| 关键词: 选区激光熔化 分区尺寸 形状误差 波纹度 表面粗糙度 |
| DOI：10.11933/j.issn.1007?9289.20211227001 |
| 分类号:TN249 |
| 基金项目:浙江省“尖兵”“领雁”研发攻关计划(2022C01117)、国家自然科学基金(52035014，51975533)和浙江省基础公益研究计划(LGG22E050036)资助项目 |
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| Influence of Divisional Size on Structural Quality of 316L Parts Printed by Selective Laser Melting |
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YANG Gaolin1,2,3, ZHU Zhaoheng1,2,3, LI Zishan1,2,3, LI Hejie1,2,3, WU Guolong1,2,3, ZHANG Qunli1,2,3, WANG Liang1,2,3, YAO Jianhua1,2,3
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1.College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023 ,China;2.Collaborative Innovation Center of High-end Laser Manufacturing Equipment,Zhejiang University of Technology, Hangzhou 310023 , China;3.Institute of Laser Advanced Manufacturing, Zhejiang University of Technology, Hangzhou 310023 , China
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| Abstract: |
| Recently, laser additive manufacturing technology has become a research hotspot in engineering, manufacturing, materials, optics, and other disciplines. Namely, it provides a new technical approach for lightweight and structural integration design and manufacturing of complex structural metal components. Selective laser melting (SLM) uses a high-energy laser beam with a diameter of 20–100 μm as the heat source to melt the metal powder and matrix surface below the powder by high-speed scanning and realizes layer-by-layer formation after cooling and solidification. Compared to other additive manufacturing technologies, SLM exhibits better forming accuracy, free forming, and a wide range of material selections. However, it is difficult to carry out the subsequent surface processing of complex structure precision metal parts manufactured by additive manufacturing, which puts higher requirements on the surface quality of SLM parts. The divisional scanning strategy can substantially enhance the surface quality of parts printed with SLM. This is because there is a large temperature gradient in the parts during the SLM forming process, which causes the expansion and contraction trends of each area in the parts to be inconsistent. This means the parts will produce large thermal stress in the forming process and exhibit a warping deformation trend. The influence of the scanning strategy on shape error and surface roughness is obtained by comparing the divisional scanning strategy with the conventional “S”-shaped scanning strategy. However, the effect of the divisional scanning size on the surface quality of printed parts is still unclear, and the undulation morphology between the divisions under the divisional scanning strategy has not been analyzed. To improve the surface quality and dimensional accuracy of cantilever structures by SLM, taking a square overhanging structure with support as the research object, a set of samples with the same specifications was designed, and the size of the samples was 25 mm × 25 mm. All the samples were added to the same support structure. The “S” shape laser scanning strategy with a reentrant width of 5 mm and the partitioned laser scanning strategy with different partition sizes (1.2, 3.6, 9.6, and 13.2 mm) were used for the samples. Using ABAQUS finite element software as the analysis tool, a numerical simulation of the SLM forming process was carried out using the thermal-mechanical coupling analysis method. The surface structure with three different wave distances, namely shape error, waviness, and surface roughness, were studied by combining numerical simulations and experiments. The profile data of the entire upper surface of the sample were obtained using confocal microscopy. The structural quality of square overhanging parts with supports was evaluated based on geometry errors, waviness, and surface roughness. The results showed that the variation trends of the geometry error, waviness, and surface roughness concerning the divisional size were different. The warpage height of the surface edge of the parts gradually decreased as the divisional size decreased. The width of the single-channel molten pool in the division gradually increased and the convexity gradually decreased. The contour fluctuation between the adjacent divisional zones gradually increased. The cross-sectional geometry error and surface roughness of the printed parts were reduced, but the waviness increased with decreasing divisional size. The surface quality of the printed parts first improved and then decreased. The increase in waviness with decreasing divisional size could be attributed to heat accumulation if the divisional size is too small. Improving the surface quality by decreasing the laser energy input by tuning the divisional size would provide a theoretical foundation for optimizing the surface quality and dimensional accuracy of cantilever structures using SLM. |
| Key words: selective laser melting divisional size geometry error waviness roughness |
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