Orbital-abrasion-assisted Electroforming of Non-rotating Parts

A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode.When cathode moves,hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing.Morphology,microstructure,surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods.Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules,disturb the crystal nucleation,and refine the grains of layer.The mechanical properties were significantly improved over traditional method.The micro-hardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV.It was confirmed that this technique had practical significance to non-rotating thin-walled parts.

Abrasive-assisted Nickel Electroforming Process with Moving Cathode

In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and transla- tion speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.

Improvement of thickness deposition uniformity in nickel electroforming for micro mold inserts

Thickness deposition is a crucial issue on the application of electroformed micro mold inserts. Edge concentration effect is the main source of the non-uniformity. The techniques of adopting a non-conducting shield, a secondary electrode and a movable cathode were explored to improve the thickness deposition uniformity during the nickel electroforming process. Regarding these techniques, a micro electroforming system with a movable cathode was particularly developed. The thickness variation of a 16 mm×16 mm electroformed sample decreased respectively from 150% to 35%, 12% and 18% by these three techniques. Combining these validated methods, anickelmold insert for microlens array was electroformed with satisfactory mechanical properties and high replication precision. It could be applied to the following injection molding process.

Manufacture of μ-PIM gear mold by electroforming of Fe-Ni and Fe-Ni W alloys

The micro gear mold for powder injection molding was made by electroforming process of Fe-Ni and Fe-Ni-W alloys using UV-lithography process. Kinetics and activation energies in electroplating of both alloys were investigated to determine the best process conditions. Fe content within electrodeposited Fe-Ni alloys increased with the increase of rotating disk speed and the decrease of temperature and it is considered from the calculated activation energy of iron content that the rate determining step is controlled by mass transfer. Iron content in Fe-Ni electrodeposit varied from 58.33% to 70.45% by increasing current density from 2 to 6 A/drn2. Also, iron content in Fe-Ni-W electrodeposit increased from 59.32% to 70.15%, nickel content decreased from 27.86% to 17.07% and the content of tungsten was almost consistent in the range of 12.78%-12.82% although the current density increases from 1.5 to 5 A/dm^2. For the electroforming of micro gear mold, SU-8 mandrel with 550 μm in diameter and 400 μm in height was prepared by UV-lithography processing. Subsequently, Fe-36Ni and Fe-20Ni-13W alloys micro gear molds were electroformed successfully. Surface hardness values of the electroformed micro molds were measured to be HV490 and HV645, respectively.

Pulse electroforming of nickel under perturbation of hard particles

Nickel deposits were prepared by pulse electroforming, in which an aluminium alloy cylinder mandrel rotated in hard particles filling between the electrodes. The microstructure and properties of the deposits were studied by contrasting with electroforming using direct current. The results show that the surface of the deposits obtained by pulse electroforming displays more obvious abrasion marks and (200) preferred orientation to that electroformed using direct current at the same average current density. Besides, the deposits represent higher microhardness and better high-temperature corrosion resistance. It is also found that the orientation index of plane (200) and microhardness significantly increase with the reduction of duty cycle of pulse current. During pulse electroforming, the longer off-time and higher peak current density are helpful to strengthening the hard particles’ polishing effect on the surface of deposits and perturbing effect on crystal nucleation of atoms.

Microstructure of Co-Ni-Al2O3 Composite Coatings by Electroforming

The metal matrix composite coatings of Co-Ni-Al2O3 were studied by electrolytic codeposition of Co-Ni alloys and Al2O3 on a Cu substrate from a sulfamate electrolyte containing Al2O3 particles. It was illustrated from the examined results of SEM, AFM and XRD that surface morphology and microstructure of Co-Ni-Al2O3 coatings appear to be mainly influenced by variations in Co content. The high Co content coatings with hcp lattice structure have a more uniform and fine structure than that of low Co content coatings with fcc lattice structure. The codeposition of Al2O3 particles in Co-Ni alloys can not change the phase structure of solid solution, only affects the growth and orientation of crystal planes and mostly increase the d value of lattice.

Electroforming of a Complex Mould Using an Acid-Mediated Copper Sulphate Bath

This work reports a procedure for the fabrication of a complex mould using the technique of electroforming. This was with a view to finding a cheaper and less labour-intensive mould production route practicable locally. A Plaster of Paris electroforming mandrel in the shape of a water bottle was produced and made electrically conducting with a layer of copper conducting paint. Considerations for electroform removal were made by applying a thin, chloroform-dissolvable epoxy layer beneath the conducting copper paint. Uniformity of deposition on the mandrel was accomplished with the construction of a special deposition bath with multiple copper anodes around its perimeter. The electroforming was done in the galvanostatic electro deposition mode for about 240 hrs in a 1 M Cu2SO4 bath with the deposition of elemental copper on the mandrel. Incidences of rising bath pH were mediated with concentrated H2SO4. A free-standing electroform representing the mould cavity was formed in the deposition. The product so formed was a reproduction of the net-shape of the mandrel exhibiting smooth surface finish. The electroforming was cast with an aluminum backing layer to complete its transformation into a split mould. The finished mould was comparable in appearance to the imported moulds in terms of appearance and reproduction of intricate surface patterns. The simplicity and low cost of this method significantly reduced the requirements for expensive instrumentation and highly skilled labour for mould production.

电化学加工虚拟仿真实验建设与应用

电化学加工现有实验教学以模型演示和装备讲解为主,学生自主学习和实验教学效果较差.基于此,开发完成了"电化学虚拟仿真实验"教学项目,营造逼真的虚拟实验环境,模拟真实电化学加工成材成形过程.学生可以根据需要选择合适的加工方式,掌握具体操作过程和工艺参数,在沉浸式环境下弄清电化学加工由"无形反应"到"有形实物"的工艺过程实质.

采用电解预刻蚀实现高界面结合强度的镍/钢微流控芯片模芯

采用微电铸工艺制作微流控芯片金属模芯的过程中,金属基底与沉积层之间的界面结合强度制约着金属模芯的成品率、制作周期、制作成本以及使用寿命。以NAK80模具钢基底和镍铸层的结合界面为研究对象,采用电解预刻蚀的方法提高界面结合强度。首先,为探究界面结合强度的影响因素,开展数值仿真研究。仿真结果表明,界面结合强度随表面粗糙度和刻蚀深度的增加均呈现增大的规律。为优选电解预刻蚀的工艺参数,开展刻蚀实验研究。实验结果表明,当电压为0~20V时,基底表面粗糙度随刻蚀电压的增加先增大后减小,优选电压为11.15V;当刻蚀电压一定时,刻蚀深度随刻蚀时间的增加而增加。为保证电沉积后铸层无缺陷,缩短电铸和后处理时间,针对60μm宽度的流道式芯片模芯,将刻蚀深度优选为30μm,以此获得优选的刻蚀时间为53s。基于以上仿真和实验结果,制作出了铸层厚度为40μm、整体尺寸为65mm×65mm的微流控芯片金属模芯。采用拉伸法测得界面结合强度为178.46MPa,相比于无刻蚀方法,电解预刻蚀后的界面结合强度提高了518.6%。

微细金属管制造技术现状与研究进展

微细金属管具有微环境下的微通道封闭、定向导向、稳流导流等功能,被广泛应用于医疗、电工电子、传热、光学等领域。受加工工具小型化、尺寸效应对材料性能和摩擦行为的改变等限制,微细金属管的制备极具挑战性。总结了微细金属管常用制备技术的制备原理、特点、制造能力以及优缺点,包括热挤压成形、冷拔成形、无模拉拔成形以及电铸成形,并对微细金属管制造技术的未来发展趋势与研究重点进行了展望。

精细金属掩模板用近零夹杂Invar合金制备技术

Invar合金是制备精细金属掩模板(Fine Metal Mask,简称FMM)的重要基材,其纯净度直接影响FMM的质量以及有机发光二极管(Organic Light EmittingDiode,简称OLED)技术的发展水平。首先概述了FMM的主要制备技术,介绍了对FMM基材Invar合金的质量要求,并对国产Invar合金箔和国外进口Invar合金箔内的夹杂物进行了表征分析。结果表明,国产Invar合金箔的纯净度与进口Invar合金箔相比,仍存在很大的差距,主要体现在夹杂物的尺寸和数量等方面。为实现OLED配套产业全国产化,攻克Invar合金的近零夹杂难题,开发新型制备技术是关键突破点。最后详细论述了超重力技术在Invar合金除杂方面的研究成果和电铸Invar合金箔应用的可行性,并指出超重力技术和电铸技术有望解决近零夹杂金属材料的制备难题。

基于阴极往复运动的TGV电铸铜实心填充工艺

玻璃通孔(TGV)转接板因其具有优良的高频电学特性,在先进封装领域受到广泛关注。然而随着TGV深宽比的不断增加,采用传统的阴极定轴旋转式电铸工艺,其填充难度与成本将随之提高。为实现高深宽比TGV的无缺陷填充,减少电铸耗时和成本,提出一种基于阴极往复运动的TGV无缺陷镀铜填充新工艺。在仿真和实验的基础上,系统研究了阴极运动方式对TGV孔内电铸液传质、离子浓度、填充速率的影响。仿真和实验结果均表明,采用阴极往复运动能有效地保证TGV孔内各处离子浓度分布的均匀一致性,减缓浓差极化,从而提高沉积速率及其上限值。在不含任何添加剂的体系中,同等沉积电位条件下平均填充速率从阴极定轴旋转式电铸工艺的6.1μm/h提高至9.2μm/h。当电位为0.5 V时,阴极往复运动方式下平均填充速率达到45.2μm/h,且电铸铜填充层中未发现孔隙缺陷。这为在无添加剂电铸铜体系中实现高深宽比TGV的无缺陷电铸铜填充提供了一种可行的低成本方案。

电铸液喷射速度对电铸铜微观组织及力学性能的影响

为了制备性能良好的电铸层,使用扫描喷射的方法进行电铸试验,研究喷射速度对电铸铜力学性能和截面微观组织形貌的影响。结果表明:低喷射速度下铜铸层的力学性能没有明显增强,但延伸性得到一定提高;而在高喷射速度下铜铸层的强度和硬度得到显著提升,同时晶粒尺寸得到均匀细化,晶粒取向更为一致。在8.3 m/s喷射速度下,铜电铸层的抗拉强度达到448 MPa。

太赫兹多层平面透镜天线的分层制造技术研究

现代信息科技的飞速发展对雷达系统提出了更高的要求,太赫兹(THz)雷达凭借其特殊的电磁特性在航空航天军事应用方面有着广阔的应用前景。高增益天线作为雷达系统的关键组成部分,在太赫兹波段的研究正受到高度关注。当天线工作频段高达1.0THz左右时,适用于低频器件的常规加工方法往往难以满足设计需求,限制了其进一步应用。本文提出并设计了一种基于UV-LIGA工艺的太赫兹多层平面透镜天线的分层制造方法,为提高透镜区域厚度均匀性,在外缘添加了片内辅助阴极作为装配区,经验证,厚度均匀性提高了33.08%。开展阶梯式电流密度电铸试验,当电流密度按1.5A/dm2、2A/dm2、1.75A/dm2阶梯变化时得到的沉积层具有更低的结合强度和表面粗糙度。透镜天线经过电性能测试,其在0.79~1.03THz范围内取得了良好的增益效果,有望应用于航空航天机载平台以提高雷达系统的识别能力。

304不锈钢电铸镍层厚度均匀性研究

为解决由于电流密度分布不均导致的电铸镍片厚度不均匀性问题,研究了电铸工艺参数和阴极挂具结构对改善镍片厚度均匀性和电铸结瘤状况的影响。结果表明,当电流密度为11 A·dm^(-2)、阳极长度为3.5 cm、极间距为2.5 cm、温度为45℃时,镍片厚度均匀性最好。此时厚度平均值为0.484 mm,极差和均方差分别为0.157 mm和0.044 mm。在最佳工艺参数下,改善挂具和设计阴极遮蔽,解决了接触点厚度薄的问题,结瘤缓解,电铸时间由10 h缩至4 h,厚度极差和均方差分别降至0.116 mm和0.036 mm。实验确定的最佳工艺条件不仅提高了镍片厚度均匀性,电铸时间也缩短了60%,提升了阳极镍粒的利用率,节约了电铸成本。

3D打印和电沉积多层超轻夹层板的力学性能和能量吸收性能

研究由开孔聚合物和金属/聚合物泡沫芯制成的轻质夹层板的力学性能和能量吸收性能。通过结合聚合物树脂的增材制造和三层金属(Ni/Ni-Cu/Ni)的电沉积制备多层夹层板,每英寸孔数(PPI)为4、5和6。测试样品在单轴压缩变形过程中的屈服强度,计算其能量吸收密度、互补能和比吸收能(SEA)。结果表明,与相同厚度的纯Ni和Cu夹层板相比,复合夹层板的性能有明显改善。增加PPI和金属层可提高力学性能和能量吸收性能,当PPI为6时,屈服强度(能量吸收密度)由聚合物夹层板的0.12 MPa(0.12MJ/m^(3))提高到三层金属夹层板的1.83MPa(0.67 MJ/m^(3))。对夹层板结构归一化能量的研究表明,夹层板具有可预测的塑性变形行为,多金属层改善了新型夹层板的力学性能。其能量吸收性能的显著增强可保证材料在不同行业的独特应用。

游离微珠材质对摩擦辅助电铸铜层力学性能的影响

[目的]研究不同材质游离微珠对摩擦辅助电铸铜层力学性能的影响。[方法]分别使用直径为0.8~1.2mm的氧化铝陶瓷微珠和氧化锆陶瓷微珠作为摩擦辅助介质进行电铸铜,对比所得Cu电铸层的表面微观形貌、截面金相组织和力学性能。[结果]氧化锆陶瓷微珠对Cu电铸层表面具有更强的磨削作用,能有效减少表面毛刺和凸起,以及起到细化晶粒的作用。使用氧化锆陶瓷微珠制备的Cu电铸层的显微硬度为147.2 HV,抗拉强度为308.3 MPa,延伸率为19.8%,分别比采用氧化铝陶瓷微珠摩擦辅助时所得的Cu电铸层高了约10.3%、5.7%和2.3%。[结论]选择合适的游离微珠作为摩擦介质可以改善电铸层的表面品质,提升其力学性能。

新赛道 新商机 新希望--变化中的网版与新赛道网版(九)

电铸网版有利于焊膏在印刷时顺利通过。便携电子产品、汽车电子、户外大型平板显示等的大量应用需求使Mini LED持续走红,电铸模版在有海量微小开孔的Mini LED模组生产中表现出优秀的能力。

新赛道 新商机 新希望——变化中的网版与新赛道网版(一)

深入剖析和对比各个时期的多种网版印刷印版的形态、材质以及制版技术等特色,重点介绍能够在不平承印物进行二次网版印刷的特殊网版、能够印刷线宽(导线、光伏栅线)仅为9μm的P1激光网版、能够印刷晶圆的超精密电铸网版,描述了网版印刷新赛道上的网版出神入化般的精彩和创新。

Microstructure and penetration behavior of electroformed copper liners of shaped charges during explosive detonation deformation

The microstructure in the electroformed copper liners of shaped charges prepared with different electrolytes was studied by Scanning Electron Microscopy （SEM） and Electron Backscattering Kikuchi Pattern （EBSP） methods. SEM observations revealed the existence of columnar grains in electroformed copper liners of shaped charges formed by electrolyte without any additive and the average grain size is about 3 μm. When an additive is introduced to the electrolyte, the grains formed in the copper liners become equiaxed and finer. EBSP results show that the columnar grain grown during electroformation has the most preferential growth direction, whereas a micro-texture does not exit in the specimen prepared by electrolyte with the additive. Further, explosive detonation deformation experiments show that penetration depth is dramatically improved when the electroformed copper liners of shaped charges exhibit equiaxed grains.