a systematic study of DRIE process for high aspect ratio microstructuring

第15卷第6期精密成形工程袁美霞，柳校可，华明（北京建筑大学机电与车辆工程学院，北京 100044）摘要：选区激光熔化技术（SLM）被认为是极有前途的增材制造技术之一，但不可逆的溅射行为严重限制了SLM技术的应用。

从粉末熔池演变、加工工艺优化和飞溅颗粒动态特征监测等方面，总结了SLM过程中飞溅行为的研究现状，分析了飞溅行为的产生机制，探讨了激光–粉末–熔池相互作用下的熔池演变情况，表明金属蒸气、Marangoni效应和伯努利效应是诱发飞溅的主要因素；讨论了加工工艺与飞溅行为的相互关系，表明通过优化工艺参数和改善打印环境以抑制飞溅是行之有效的方法；阐述了飞溅诱导缺陷的机理，并讨论了SLM过程的监测方法，表明单一信号的局限性会导致监测结果失准，多信号融合监测是提升精准性的重要方法之一。

最后，针对飞溅行为存在的关键科学问题和技术难题，展望了SLM加工中飞溅行为的研究方向。

关键词：SLM技术；增材制造；飞溅机制；内部缺陷；飞溅监测DOI：10.3969/j.issn.1674-6457.2023.06.020中图分类号：TF121 文献标识码：A 文章编号：1674-6457(2023)06-0163-11Research Progress of Splashing Behavior in Selective Laser MeltingYUAN Mei-xia, LIU Xiao-ke, HUA Ming(School of Mechanical-electronic and Vehicle Engineering, Beijing University of Civil Engineering and Architecture,Beijing 100044, China)ABSTRACT: Selective Laser Melting (SLM) is considered one of the most promising additive manufacturing (AM) technolo-gies, but the irreversible sputtering behavior severely limits the application of SLM. The work summarized the research status of splashing behavior in SLM from the aspects of powder melt pool evolution, processing process optimization, and dynamic monitoring of splashed particles. The mechanism of splashing behavior was analyzed, and the evolution of melt pool under the interaction of the laser powder molten pool was explored. It showed that metal vapor, Marangoni effect, and Bernoulli effect were the main factors inducing splashing. The interaction between processing technology and splashing behavior was discussed, indicating that optimizing process parameters and improving the printing environment were effective methods to suppress splashing. The mechanism of splash-induced defects was elaborated, and the monitoring methods of SLM process were dis-cussed. It showed that the limitations of a single signal could lead to inaccurate detection results. Multi signal fusion monitoring was an important method to improve accuracy. Finally, in response to the key scientific and technical challenges in studying收稿日期：2023–03–07Received：2023-03-07基金项目：国家重点研发项目（2022YFC2406004）；北京建筑大学研究生创新项目（PG2022134）Fund：National Key Research and Development Projects(2022YFC2406004); Beijing University of Architecture Graduate In-novation Project(PG2022134)作者简介：袁美霞（1979—），女，博士，副教授，主要研究方向为增材制造。

高压法聚乙烯管式反应器模拟研究何加强(中国石化股份有限公司齐鲁分公司塑料厂，山东淄博255411)Simulation of a High-pressure Ethylene Polymerization Tubular ReactorHe Jiaqiang(Plastics Complex of Qilu Branch Co.,SINOPEC,Zibo255411,China)Abstract:A tubular polyethylene reactor model was established in Aspen Plus.The effects of the reactor temperature peak value,initiator ratios and reactor cooling water temperature on the molecular chain structure,ethylene conversion rate and initiator consumption were investigated respectively.The results show that the number average molecular weight of LDPE is mainly affected by the reactor temperature peak value when the modifier is constant,and the molecular weight distribution of LDPE is mainly affected by the cooling water temperature and the reactor temperature peak values.Meanwhile,the ethylene single-pass conversion is mainly affected by the cooling water temperature,and the initiator consumption is mainly affected by the reactor temperature peak values of the upstream reaction zone and the initiator ratios.Keywords:free radical polymerization；polyethylene；tubular reactor；simulation；molecular chain structure高压聚乙烯工艺生产的低密度聚乙烯(LDPE)是三大聚乙烯通用树脂中最早实现工业化生产的聚乙烯塑料产品，具有优良的透明性和加工性，其薄膜制品、电气绝缘材料、注塑、吹塑制品、涂层、板材、管材等在工农业生产和日常生活中得到普遍应用。

MAGMA操作教程一、基本操作流程建构实体模型 CAD ModelCAD Model模流前处理 PreprocessorPreprocessor实体切网格 MeshingMeshing参数设定 ParametersParameters模流后处理PostprocessorPostprocessor结果分析AnalysisAnalysis相应对策DecisionDecision图,1_1,建构正确的实体模型是进行分析工作的关键。

把实体分为不同的组～转换为.stl档～为MAGMA分析做好准备。

如图,1_1,所示:黑色字体是使用MAGMA的操作步骤,红色字体是分析的前期工作和后期对策。

二、,,,,,的操作,、创建专案图,2_1, 图,2_2,1图,2_3, 图,2_4,专案名称.stl档图,2_5,说明:图,2_1,打开桌面图标 project菜单 create project 出现新对话框图,2_2,选择Iron casting铸铁模组选择结果存放路径,MAGMAsoft下, 取解析方案名称回车键 OK 出现新对话框图,2_3,默认系统选择直接按红框所标的键～直到图,2_4,,按OK键结束创建专案操作。

如图,2_5,的路径～把建立好的.stl档存在CMD文件夹下。

,、前处理2,1 、材质群组介绍2,、砂模(sandm)Z轴正向 ,、灌口(inlet) Inlet,、浇道(gating),、浇道(gating)Gating ,、冒口(feeder) Gating,、冒口(feeder),、入水口(ingate),、入水口(ingate),、砂芯(core),,、冷铁(chill),,、铸件(cast) FeederCore Ingatechill图,2_6,在载入时一定要确保重力方向向上～如图,2_6,所示。

一般在实体建模时便给出正确的重力方向。

如果方向错误也可在MAGMA内修改。

,见后面说明, 砂模可以在建构实体时绘出～也可以在MAGMA内绘制出。

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1. 1. Introduction
Recently, the increase in the already large amount of acidic wastewater generated by semiconductor manufacturing plants during etching processes, which contains fluoride (FÀ), nitrate (NO3À), and phosphate (PO4nÀ) anions, has become a serious environmental concern [1]. Furthermore, phosphate and nitrate have been introduced into the environment through sewage treatment effluent, surface runoff carrying fertilizers, and many other human activities, which has deteriorated water quality, resulting in algal bloom and depletion of dissolved oxygen in water media [2]. Thus, the demand for treatment of these anions has been persistently increasing to maintain a clean environment and supply safe drinking water.
a Department of Chemical and Biomolecular Engineering (BK21 program), KAIST, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea b Advanced Biomass R&D Center, KAIST, 291 Daehakno, Yuseong-gu, Daejeon 305-701, Republic of Korea c Department of Chemical & Biochemical Engineering (BK21 program), Chosun University, Seosuk-dong, Dong-gu, Gwangju 501-759, Republic of Korea