微细光成形和LIGA工艺集成的可行性分析

微机电系统的发展，对微细加工技术提出了更高的要求。目前常用的微细制造技术本质是基于掩模光刻的二维半微加工技术，难以进行真三维结构的制造。对单光子和双光子微细光成形技术的成形原理、加工分辨能力进行分析和实验研究，将其与微细电铸等工艺集成，提出一种能实现真三维制造的、具有不同应用材料的微细加工新方法，并从原理上验证了两者集成的可行性，为后续研究奠定了基础。微细光成形与微细电铸集成工艺技术为进一步拓展微细制造技术提供了新途径。     

电铸技术的应用与发展趋势

采用电铸工艺能制造用常规机械加工方法无法制造的精密零件。随着各种复杂微细的精密异型金属零部件在需求量上的大幅增加,精密零件电铸制造技术在全世界范围内受到高度重视,促使电铸技术得到了进一步发展。另外,由于电化学领域的新进展又为电铸技术的发展创造了条件,目前,特型零件电铸工艺方法、新型高性能电铸材料及电铸装备的研究等为电铸技术发展方向。     

采用过电铸工艺制造金属微细阵列网板

针对制作尺度10μm的超小微细阵列网板非常困难的问题,提出了采用过电铸工艺制造超小尺寸微细阵列网板的方法。建立了过电铸工艺过程的电场模型,利用有限元分析技术对过电铸工艺过程进行模拟仿真。选取优化的工艺参数(烘胶120℃/60min,曝光3000mJ/cm2,显影2min等)利用光刻制作了高度为50μm、直径为50μm的AZEXP125nXT-10A光刻胶群柱结构,以此胶膜结构作为模具进行了过电铸工艺实验,并与仿真结果进行对比,结果证明了有限元仿真的正确性。最后,通过过电铸缩孔2h获得了厚度达70μm,孔径为4μm的微细阵列网板结构。实验表明,过电铸工艺是一种低廉、安全、可批量生产的制作超小阵列网板的方法。     

电铸工艺对工具电极材料抗电蚀性能的影响研究

提升基于准LIGA工艺制作的微细电火花加工工具电极材料的耐电蚀能力,是准LIGAMicroEDM组合加工高深宽比三维微结构可靠实现的重要研究内容。论述了该组合加工的技术优势及其工艺路线,理论分析了电铸电极材料电蚀性的影响因素,试验研究了电沉积工艺参数和操作条件如添加剂种类及其添加量、电流密度、温度等对电铸铜工具电极电蚀能力的影响。结果表明,组合添加适量明胶和Cl-,在适当的电流密度和温度等工作条件下,电铸出的铜工具电极在微细电火花加工中表现出超强的耐电蚀能力,重量相对损耗为0.3%。     

选择性射流电铸技术初探

电铸作为一种精密制造技术 ,在许多高技术领域得到成功的应用。然而 ,电铸存在的缺陷严重制约了其应用和发展。本文分析了导致电铸缺陷的主要原因和解决方法 ,提出了选择性射流电铸工艺方案。最后通过试验对射流电铸的基本工艺特性进行了研究 ,并验证了选择性射流电铸工艺的可行性     

超声微细电铸试验研究

试验研究和分析了电解液施加超声搅拌作用时不同声强对试样形貌质量的影响,优选了工艺参数,在此基础上,进行了超声微结构电铸试验,并制备出多种金属微器件。试验结果表明：超声搅拌声强为12～14W／cm^2时,电铸出的镍微器件积瘤、针孔等缺陷少,塌角、圆边现象明显减少,表面平整。微细电铸时,电解液施加适量大小声强的超声搅拌,能显著改善微细电铸器件形貌质量,提高金属充填能力。     

微细电铸Over-plating成型过程的数值模拟与实验研究

微细电铸的Over-plating过程对电铸成型金属器件的质量有直接影响。通过有限元方法对微细电铸过程的电场进行建模分析,利用迭代边界法对Over-plating动态过程的阴极电流密度分布进行数值模拟;通过对直径300μm、深100μm微孔结构的电铸实验,得到了不同时间下Over-plating过程的电铸层形貌;实验结果与数值模拟有着很好的一致性,表明基于有限元的迭代边界分析方法是合理的,也为后续对微细电铸Over-plating成型过程的定量分析提供了参考。     

大面积微细结构的电火花高效加工

采用深度光刻与电铸技术相结合较好地解决了大深宽比的电火花工具电极的制造问题。在此基础上,利用优化的微细电火花加工工艺,可以实现大面积微细结构的高效、精细制造。     

金属微结构阵列的电铸成型

在分析微细电铸的电场与流场特性的基础上,深入研究了铸层厚度的不均匀现象及搅拌方式和电流密度对微细电铸质量的影响.由于高深宽比胶膜的存在,单一搅拌对电铸区域的影响只集中在微区的入口部分,扩散过程成为金属沉积的限制性因素;随着胶膜深宽比的增大,电场等势线弯曲的程度加大,导致电铸微区内金属离子传输能力不均匀.实验表明:微细电铸过程中,搅拌速度提高并不能改善金属沉积的传质条件,辅助超声的复合搅拌在相同条件下能提高金属沉积速度,减少铸层缺陷;最佳电流密度不宜超过0.9～1.0 A/dm2.基于该项技术,实现了高分辨率、侧壁陡直金属微结构的电铸成型.     

用SU-8胶加工微结构的试验研究

以正交实验设计为研究方法,对采用负性光刻胶（SU-8）加工高分辨率和高深宽比微结构进行了工艺研究,得出：前烘温度与前烘时间对光刻质量影响最大,对120~340μm厚的光刻胶,前烘温度取90℃,前烘时间50~120min时图形质量最佳。分析了高深宽比微结构电铸的特点,实验表明传质是微细电铸的限制性环节。实现了光刻、电铸加工微结构的工艺参数优化。     

电铸制备SiC颗粒增强镍基复合材料的工艺与性能

采用电铸技术(氨基磺酸镍电铸液)成功制备了SiC颗粒增强镍基复合材料;用Leica Qwin图形分析软件和显微硬度计分析了电铸工艺参数对SiC颗粒增强镍基复合材料中SiC颗粒含量以及SiC含量对该复合材料显微硬度的影响;用场发射扫描电镜分析了复合材料的截面形貌和SiC分布.结果表明:在SiC加入量50 g·L-1、电流密度3 A·dm-2和磁力搅拌强度1.5次/min条件下,复合材料中SiC颗粒体积分数达到最高值27%,其显微硬度值也最高,为710 HV.     

喷射电沉积快速成形的定域性实验研究

介绍了喷射电沉积快速成形技术的基本原理，分析了金属零件成形过程中，定域性对零件成形精度的重要性，并对影响定域性的因素进行了基础实验研究。结果表明：喷嘴口径、喷嘴与阴极间的距离对定域性有密切关系，喷嘴口径小、喷嘴距离小，则定域性好，尺寸精度高；阴极电流密度和喷嘴扫描速度对定域性亦有影响，阴极电流密度低、喷嘴扫描速度快，则金属沉积斑尺寸小，定域性好。     

Vacuum suction aid for microlens array formation using LIGA-like process

Microlens array fabrication using a vacuum suction process combed with the LIGA-like process is presented in this paper. The circular patterned array was designed on a photomask and transferred onto a substrate using photoresist patterning. Electroforming technology was used to convert the photoresist patterns into a metallic molds with an array of nozzles. Liquid JSR resist was spun onto the substrate joining the metallic mold to remove microlens array under vacuum conditions. The exposure energy and vacuum pressure were essential parameters in the microlens array manufacturing process. Microlens arrays with 50 μm in diameter at −50 cm-Hg vacuum pressure and 100 μm in diameter at −60 cm-Hg vacuum pressure were successfully formed. The produced microlens arrays presented smooth measured surface profiles coincident with the optical lens geometry.     

Vacuum suction aid for microlens array formation using LIGA-like process

Microlens array fabrication using a vacuum suction process combed with the LIGA-like process is presented in this paper. The circular patterned array was designed on a photomask and transferred onto a substrate using photoresist patterning. Electroforming technology was used to convert the photoresist patterns into a metallic molds with an array of nozzles. Liquid JSR resist was spun onto the substrate joining the metallic mold to remove microlens array under vacuum conditions. The exposure energy and vacuum pressure were essential parameters in the microlens array manufacturing process. Microlens arrays with 50 μm in diameter at -50 cm-Hg vacuum pressure and 100 μm in diameter at -60 cm-Hg vacuum pressure were successfully formed. The produced microlens arrays presented smooth measured surface profiles coincident with the optical lens geometry.     

A promising thermal pressing used in fabricating microlens array

This paper describes a simple and inexpensive technique for designing and fabricating polygon microlens arrays using a thermal pressing process. Polygon microlens array molds were fabricated using lithography and an electroforming process. The microlens patterns were designed on a photomask and transferred to a substrate through photoresist patterning. Electroforming technology was used to convert the photoresist microlens patterns into metallic molds. A hot pressing machine was then used to produce the microlens array in a polycarbonate (PC) substrate. The experimental variables were compression pressure, temperature, and the pressing time. The surface roughness of the produced microlens array was measured using atomic force microscopy (AFM). The average microlens radii of curvature ranged from 315 to 420 μm and the average sag heights were from 2.98 to 4.03 μm, respectively. The experimental result showed that this fabrication process is useful for microlens array production.     

Error calculation for corrective machining with allowance requirements

Electroforming copper from the copper sulfate baths or the pyrophosphate baths is one of commonly used methods for manufacturing electro-discharge machining (EDM) tool electrode, in particular for the fabrication of micro- and meso-scale tool electrodes with complex cross-section, but few literature on the electrode-wear performance of electroformed copper electrode has been available until today. To better select copper tool electrode materials, the wear resistance of the macroscopic and tiny copper tool electrodes deposited from the copper sulfate baths and the pyrophosphate baths were investigated comparatively with the same micro-EDM parameters. The optimal electrodeposition parameters in which the deposited copper had the lowest electrode-wear ratio were first obtained from the two baths, respectively. And then, the wear resistance of the micro-featured copper tool electrode electroformed using the optimal deposition conditions from the two baths were evaluated comparatively. Experimental investigations showed that, both at the macro-scale level and at the micro-scale level, the copper tool electrode electroformed from the pyrophosphate baths (the smallest electrode-wear ratio was 10% for the macro-electrode and 12.8% for the micro-electrode) exhibited better wear resistance than that deposited from the copper sulfate baths (the smallest electrode-wear ratio was 11.95% for the macro-electrode and 17.3% for the micro-electrode).     

制造加工约束下连续体拓扑优化的数值实现

针对两类常见的制造加工约束即对称性和重复性下的连续体拓扑优化问题,提出了将敏度值在每轮优化前的修正方法,该方法简单且易于编程实现,实现了对称性或重复性约束条件下连续体拓扑优化设计,通过数值算例对不同制造加工约束下的拓扑结果进行了分析对比,结果表明,研究方法具有可行性和有效性。     

焊接电弧光谱的分布特征

在试验的基础上,给出了焊接电弧光谱的频域及空间分布的测试结果,分析了焊接电弧光谱的结构。通过分析得出了ＴＩＧ焊电弧光谱空间分布的差异性和ＭＩＧ焊电弧光谱空间分布的相似性,着重指出ＭＩＧ焊电弧光谱与熔滴过渡之间存在密切关系。此外,还对焊接电弧光谱特征的应用提出了方向。