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1.
Lubrication for Micro Forming of Ultra Thin Metal Foil 总被引:1,自引:0,他引:1
The objective of the present investigation is to establish lubrication technique in micro forming operation. Conventional lubricant, in general, cannot be applied directly to micro forming process, since the lubricant thickness is similar to the dimensions of feature size in micro forming operations. In present investigation, the Octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) was chosen as a potential lubricant because it sticks to Si wafer die and can be applied to surface with uniform thickness of several nanometer thick. Friction coefficient and adhesion force were measured for OTS SAM coated wafer. It is shown that OTS SAM coated Si wafer offers substantially lower friction and lower adhesion than bare Si wafer. Micro channel wafer die was coated with OTS SAM and channel forming operation with 1μm thick copper foil was carried out. Experimental results show that OTS SAM coated wafer die improves forming characteristic of ultra thin copper foil substantially. These results show that SAM coating can be used as a lubricant in micro forming successfully. 相似文献
2.
Jae Sung YOON Tae-Jin JE Doo-Sun CHOI Sung Hwan CHANG Kyung-Hyun WHANG 《中国有色金属学会会刊》2011,(Z1):100-103
A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can be made on the micro channels. The micro channels were made on the silicon substrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns. 相似文献
3.
Jenn-Terng Gau Po-Han Chen Hao Gu Rong-Shean Lee 《Journal of Materials Processing Technology》2013,213(3):376-382
In order to understand the coupling influence of size effects and strain rates on the formability of the austenitic stainless steel 304 foils in micro scale, a series of micro scale limited dome height (LDH) tests were designed and conducted in three different speeds without lubricant on the annealed and as-received austenitic stainless steel 304 foils. In this study, a technique was developed to coat a layer of pure chromium (≈0.3 μm thick) on the foils and by using the etching process to make the micro square grids (50 μm × 50 μm) on the foils. Then, the foils were annealed at different temperatures for obtaining different microstructures. A set of the forming limit curves (FLC) of the foils were obtained and they can be used by industry right away for product design, process design and development, die design, and simulations, etc. Besides, the coupling influence of the size effects and the strain rates on the formability of the austenitic stainless steel 304 foils has been studied, observed and understood. 相似文献
4.
Huixia Liu Zongbao Shen Xiao Wang Hejun Wang Maoke Tao 《International Journal of Machine Tools and Manufacture》2010,50(5):491-494
A novel process technology for micro punching of thin sheet metals is presented in this paper. The laser induced shock waves act as the micro punch. The forming speed can be controlled by adjusting the laser energy. Micro holes of 250 μm in diameter were successfully punched on sheet metal of 10 μm in thickness by single pulse, and good edge quality was obtained. The micro die-opening is produced by electrical discharge machining (EDM) using the copper electrode of φ=220 μm. In the experiment, a sacrificial coating is used to generate high-pressure plasma under a laser pulse, so no signs of melting, burning, or ablation were observed on the workpiece. The novel process of micro scale laser high speed punching is also numerically studied. In addition, this method can be used to fabricate noncircular micro holes on thin sheet metals with noncircular micro die-openings. With further development, laser high speed punching may become an important micro punching technology, which is characterized by non-contact, low cost, and high efficiency. 相似文献
5.
Yan-pu ChaoAuthor Vitae Le-hua QiAuthor Vitae Yuan XiaoAuthor Vitae Jun LuoAuthor Vitae Ji-ming ZhouAuthor Vitae 《Journal of Materials Processing Technology》2012,212(2):484-491
Metal micro-droplet deposition manufacturing technique is a novel direct metal rapid prototyping for building the miniaturized parts. In this paper, the novel direct metal rapid prototyping was proposed to fabricate micro thin-walled metal parts. A direct droplet fabrication experimental system was developed based on the forming principle of micro-droplet deposition manufacture. Several deposition experiments were conducted to investigate the influences of process parameters on the formed wall thickness and deposition accuracy of droplets. The experimental results show that the proper deposition distance Hs for obtaining high deposition accuracy of droplet ranges from 1 mm to 20 mm; the formed wall thickness W can be controlled by selecting different nozzle diameters D and formed angle of deposited droplet θ. According to the experiment results, a micro thin-walled structure with wall thickness of 400 μm was fabricated by adjusting the process parameters. The above research works show that it is feasible to fabricate the micro thin-walled metal parts by micro-droplet deposition manufacturing technique. 相似文献
6.
A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can be made on the micro channels. The micro channels were made on the silicon substrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns. 相似文献
7.
Ni-base metal–intermetallic laminate composites were obtained from in situ reaction synthesis between Ni and Al foils by utilizing plasma activated sintering. The effects of Ni foil thickness on the microstructure and tensile properties of the composites were investigated. The results show that the phases forming during reaction synthesis are independent of the starting thickness of the Ni foils. However, thicker reacted layers are obtained in the samples fabricated from 100 lm Ni foils(Ni100) than those obtained in the samples from 50 lm Ni foils(Ni50)when treated at the same process. The tensile strength of Ni100 samples increases with the temperature increasing at the expense of ductility. Dissimilarly, Ni50 composites treated at higher temperatures exhibit enhanced strength and ductility. Both Ni50 and Ni100 laminate fracture in a similar mechanism. Cracking first occurs in the brittle intermetallic layers. These original cracks result in shear bands in Ni layers emitted from the crack tips, and thus producing local stress concentration, which initiates new cracks in adjacent intermetallic layers. The multiplication of cracks and shear bands leads to the failure of the laminates. 相似文献
8.
Tensile Test of very thin Sheet Metal and Determination of Flow Stress Considering the Scaling Effect 总被引:1,自引:0,他引:1
H. Hoffmann 《CIRP Annals》2006,55(1):263-266
The reduction in size of mechanical parts is becoming more and more important in metal forming processes. This trend towards miniaturization leads to new requirements regarding the material and the product. The main object of this research is the so-called scaling effect which can occur during the forming process of very thin sheet metals. The goal is to determine and investigate variables which considerably influence the scaling effect. The optimisation of such forming processes needs a more comprehensive use of simulation and finite element analysis. The conventional model used for large and thick sheet specimens is not sufficient yet. Existing research reports on this topic show that among other things the thickness and the grain size of the material influence the scaling effect. Thus it is important to consider these material characteristics in the determination of the flow stress curve. In this paper the flow stress curve is investigated on a micro scale of up to 10μm specimen thickness considering different sheet thicknesses and widths. 相似文献
9.
《CIRP Annals》2019,68(1):257-260
For prediction and prevention of surface roughening in micro metal formings, a new model to represent material inhomogeneity and an original method to determine the material inhomogeneous parameters were proposed. A series of micro deep drawing were carried out by employing metal foils with thickness of 0.05 mm and average grain size of 16.7 μm. The validity of the proposed model and method were verified with respect to prediction of surface roughening in the tested micro deep drawings. It has become clear that the proposed model and method for predicting product accuracy in manufacturing medical and electrical micro parts. 相似文献
10.
Flange forming is a process which is wide spread in macro range for blanks with thicknesses from less than 1?mm up to several millimeters. Flange formed geometries are used as preforms for threads but also as device to give guidance and contact face to bolts and axles in sheet metal. A great advantage of flange forming compared to other machining processes is low process cycle time combined with high material utilization. Thus, a reasonable repertoire of knowledge has been gained for flange forming in macro range. Due to ongoing miniaturization of today??s products, flange forming is an interesting process applicable in micro range as well whereas size effects do not generally allow transfer of process limits from macro to micro range. Therefore the maximum flaring ratio for flange forming in micro range for sheet metal foil of 10?C25???m for a stainless steel 1.4301 and Copper E-Cu58 is investigated and compared with results in macro range. It is shown that the maximum flaring ratio decreases with decreasing sheet metal thickness. The resulting flange heights of experiments are compared with theoretical estimations which show a good accordance. 相似文献
11.
12.
A new approach to optimal design of multi-stage metal forming processes with micro genetic algorithms 总被引:3,自引:0,他引:3
S. Roy S. Ghosh R. Shivpuri 《International Journal of Machine Tools and Manufacture》1997,37(1):29-44
This paper describes a new method for design optimization of process variables in multi-stage metal forming processes. The selected forming processes are multi-pass cold wire drawing, multi-pass cold drawing of a tubular profile and cold forging of an automotive outer race preform. An adaptive micro genetic algorithm (μGA) scheme has been implemented for minimizing a wide variety of objective-cost functions relevant to the respective processes. The chosen design variables are die geometry, area reduction ratios and the total number of forming stages. Significant improvements in the simulated product quality and reduction in the number of passes has been observed as a result of the micro genetic algorithms-based optimization process. 相似文献
13.
Chao Zheng Sheng Sun Zhong Ji Wei Wang Jing Liu 《International Journal of Machine Tools and Manufacture》2010,50(12):1048-1056
Micro scale laser bulge forming is a high strain rate micro-forming technique, which employs the shock wave pressure induced by a laser pulse to deform thin metals to 3D configurations. The process holds promise for fast setup, well-controlled, high efficiency and precision of fabrication of complex miniaturized devices. In this paper, micro scale laser bulge forming of pure copper was investigated using both numerical and experimental methods. A finite element model was proposed to simulate the dynamic deformation of the shocked material, and the simulation results were validated by experiments. With the verified model, the deformation mechanism of the transient forming process was characterized through the evolution of equivalent plastic strain rate and the distributions of strains and residual stresses. In addition, the effects of laser energy, die diameter and sample thickness on the forming behavior of copper foils were studied. The experimental and numerical simulation results show that with an increase of sample thickness, the deformation depth decreases, while it becomes larger as the enhancement of laser energy. The shock forming process is not very sensitive to the diameter of the die, indicating that it is feasible for micro products in a wide dimension range. 相似文献
14.
Dissimilar metal joining of aluminum alloy to galvanized steel with Al-Si, Al-Cu, Al-Si-Cu and Zn-Al filler wires 总被引:8,自引:0,他引:8
Honggang Dong Wenjin HuYuping Duan Xudong WangChuang Dong 《Journal of Materials Processing Technology》2012,212(2):458-464
Aluminum alloy sheets were lap joined to galvanized steel sheets by gas tungsten arc welding (GTAW) with Al-5% Si, Al-12% Si, Al-6% Cu, Al-10% Si-4% Cu and Zn-15% Al filler wires. Different amounts of Si, Cu and Zn were introduced into the weld through different filler wires. The effects of alloying elements on the microstructure in the weld and tensile strength of the resultant joint were investigated. It was found that the thickness of the intermetallic compound (IMC) layer decreased and the tensile strength of the joint increased with the increase of Si content in the weld. The thickness of the IMC layer could be controlled as thin as about 2 μm and the tensile strength of the dissimilar metal joint reached 136 MPa with Al-12% Si filler wire. Al-Si-Cu filler wire could result in thinner interfacial layer than Al-Cu filler wire, and fracture during tensile testing occurred in the weld for the former filler wire but through the intermetallic compound layer for the latter one. A Zn-rich phase formed in the weld made with Zn-15% Al filler wire. Moreover, the Zn-Al filler wire also generated thick interfacial layer containing a great amount of intermetallic compounds and coarse dendrites in the weld, which led to a weak joint. 相似文献
15.
应用微型储能焊机实现了厚度为25---35 μm的Zr55Cu30Al12Ni3非晶箔材的快速凝固连接. XRD测试表明, 接头仍为非晶结构. 计算的接头冷却速率高达106 K/s, 远大于形成锆基非晶合金的临界冷却速率, 有效地抑制了接头区的晶化. 接头尺寸微小, 直径为60---90 μm, 未产生气孔、夹杂等焊接缺陷. 接头剪切强度高达1141 MPa. 高的电阻率特性使非晶合金的焊接能量明显低于晶态合金. 相似文献
16.
铸轧铝带的表层夹杂特征及其遗传危害 总被引:1,自引:1,他引:0
采用SEM和EDAX分析技术,观察和分析了铸轧铝带的表层夹杂缺陷。结果表明,夹杂尺寸大约在5-200μn之间,夹杂含有O,C,S,Cl,Na,Fe,Mg,Si等元素。原辅材料中的杂质、熔炼铸轧过程的污染及净化处理不当是形成夹杂的原因。表层夹杂的遗传将导致箔材断带和弥散性穿孔。严格控制和改进工艺,可以有效地防止夹杂形成。 相似文献
17.
This paper describes the fabrication of SOI structures with buried cavities using SDB and electrochemical etch-stop. These
methods are suitable for thick membrane fabrication with accurate thickness, uniformity, and flatness. After a feed-through
hole for supplied voltage and buried cavities was formed on a handle Si wafer with p-type, the handle wafer was bonded to
an active Si wafer consisting of a p-type substrate with an n-type epitaxial layer corresponding to membrane thickness. The
bonded pair was then thinned until electrochemical etch-stop occurred at the pn junction during electrochemical etchback.
By using the SDB SOI structure with buried cavities, active membranes, which have a free standing structure with a dimension
of 900×900 μm2, were fabricated. It is confirmed that the fabrication process of the SDB SOI structure with buried cavities is a powerful
and versatile technology for new MEMS applications. 相似文献
18.
19.
通过等离子体喷射法硅衬底制备金刚石的试验,研究了硅片规格、硅片前期预处理、金刚石膜沉积以及后期热处理等对制备复合基片性质和裂纹产生的影响,对各个工序进行优化和改进,确定了制备金刚石膜/硅复合基片最佳的工艺流程.实验结果表明:在硅基片制备的金刚石膜厚度大于20 μm,抛光后金刚石膜表面粗糙度Ra达到5.2 nm,剩余金刚... 相似文献
20.
This study develops a micro wire electrochemical cutting process. Because of no electrode wear in this process a very thin metal wire can be used as the wire electrode. The tungsten wire electrode with the diameter of 5 μm is electrochemically in situ fabricated for the production of micro structures with the slit width of less than 20 μm. Effects of process parameters on the wire diameter in the wire etching and on the gap variation in the electrochemical cutting have been studied theoretically and experimentally. Many complex micro metal parts with structures of several ten micrometers have been obtained. 相似文献