共查询到18条相似文献,搜索用时 156 毫秒
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2 m SiC 反射镜拱形轻量化结构设计 总被引:1,自引:0,他引:1
针对口径为2 060 mm 的地基大口径望远镜主反射镜,选用SiC 材料和新型拱形轻量化结构进行了详细的轻量化参数设计,并对支撑环半径进行了优化.对于Whiffle tree 18 点支撑和27 点支撑形式,从静力学(重力作用)和热力学两方面对比分析了两种轻量化结构的镜面变形,结合SiC 反射镜的加工工艺,最终确定18 点支撑的轻量化结构为首选方案.同时,就SiC 反射镜对稳态温度差导致的热变形较敏感的问题,提出可通过设计与镜体热变形相匹配的支撑结构来满足镜面变形的要求. 相似文献
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采用解析法和有限元分析方法,分析了各因素对电火花加工表面质量的影响,提出了一种在电火花放电加工过程中逐级改变加工电规准,并依次加大电极的摇动量进行镜面加工的方法.提出应用白光干涉方法测量镜面加工工件表面质量的微观形貌,具有非接触、高精度等特点,垂直分辨力达到纳米级.实验表明在非混粉加工液中,不更换电极且被加工工件为45#钢的情况下,利用白光干涉测量法检测出电火花镜面加工的工件表面粗糙度Ra为0.02μm,满足电火花镜面加工精度的要求. 相似文献
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可电火花加工的导电碳化硅(SiC)陶瓷不仅可以克服传统高电阻率SiC陶瓷难加工的突出缺点,而且能够保留传统高电阻率SiC陶瓷的其他优异性能,在结构陶瓷领域取代传统的高电阻率SiC陶瓷具有突出优势。本文阐述了粉末烧结制备氮掺杂导电SiC陶瓷的原理,归纳总结分析了其粉末烧结制备方法、烧结助剂的种类及其所获得SiC陶瓷的热电和力学性能。同时,探讨了SiC陶瓷的电性能影响因素,为调控SiC陶瓷的电性能提供了参考依据。最后,指出了氮掺杂导电SiC陶瓷面临的主要挑战,在未来研究中,应聚焦于发展新烧结技术与烧结添加剂体系以及澄清电性能调控机制,为制备电阻率可控的高性能导电SiC陶瓷奠定技术基础。 相似文献
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N. K. Francis K. G. Viswanadhan M. M. Paulose 《Materials and Manufacturing Processes》2016,31(7):969-975
Swirling Fluidized Bed Machining (SAFBM) is a nontraditional machining process and novel variant of Fluidized Bed Machining (FBM) in which the former has overcome certain drawbacks of the latter such as roughness variation and shading effect. SAFBM generates significant material removal and surface finish on the workpiece surface during the machining process with consistency and flexibility. The present detailed study emphasizes on the machining of softer materials such as brass and aluminum using abrasive particles such as silicon carbide in order to analyze the effect of various micro-cutting mechanisms on the generation of surface texture. This study examines the evolution of surface roughness profile after progressive machining with abrasives ranging from coarse, medium and fine grades of SiC with the help of optical microscopic images of the machined surface. The research concludes that using SAFBM, flat and uniform surface finishing with modification ratio in terms of roughness parameters ranging from 5 to 7 is possible within 7–8 hours of processing. 相似文献
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光学微结构的超精密加工技术 总被引:8,自引:2,他引:6
微结构光学元件在光电产品及光通讯产品中的应用日益广泛,采用多轴超精密机床加工光学微结构,可达到亚微米级形状精度和纳米级表面光洁度的高精度水平,详细介绍了光学自由曲面及光学微结构的超精密加工技术,并开发了适合超精加工微型槽和微透镜列阵的刀具轨迹自动生成软件。 相似文献
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This article studies the effect of surface finish on the corrosion behavior of magnesium ZM51/SiC composite. Four different machining processes were employed: single-point diamond turning, wire electrical discharge machining, grinding, and polishing. The machined surface quality was found to have a significant influence on the corrosion behavior of magnesium ZM51/SiC composite. The results showed that, in terms of corrosion current, charge transfer resistance, and double-layer capacitance, the polished and fine-ground specimens have the highest corrosion resistance whereas the rough-ground specimen exhibited the highest corrosion rate. The effects of the various machining-induced defects on corrosion behavior are discussed. 相似文献
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Liping Shi Yu Fang Qingwen Dai Wei Huang 《Materials and Manufacturing Processes》2018,33(13):1415-1421
The multiphase microabrasive jet machining is a new type of surface texturing technique using compressed air to accelerate the mixtures of abrasive and water to remove material. It is effective for surface texturing on different materials, and can also reduce the pollution and cost by recycling the microabrasive particles easily. Basing on this technique and using the micro synthetic diamond as the abrasive, a multiphase jet technique is developed for machining on silicon carbide (SiC) surfaces. The processing results are compared to other abrasives, and influences of the processing parameters such as jet distance, jet pressure, abrasive concentration, particle size, and jet angle are investigated experimentally. The improvement on machining quality and efficiency are confirmed. 相似文献
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Tosin Tomori Shreyes N. Melkote Mahesh Kotnis 《Materials and Manufacturing Processes》2003,18(6):943-963
An experimental study was conducted to examine the material properties and machinability of a silicon carbide (SiC)-filled epoxy conductive tooling system (RP4037 CAST-ITTM). Specifically, the effects of SiC filler concentration and machining process parameters (cutting speed and feed) on the physical and material properties, resultant cutting force, surface integrity, and tool wear were studied. Machinability evaluation was carried out using the end milling process. The study showed that an increase in filler concentration significantly increased the density, thermal conductivity, resultant machining forces, surface roughness of the machined surface, and tool wear. However, it had insignificant impact on the glass transition temperature, strength, or hardness. A decrease in material strength was observed with increasing cutting speed and feed. Increasing filler concentration was also found to degrade the machined surface morphology. Possible explanations for the observed effects are discussed. 相似文献
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The present work is focused on optimization of machining characteristics of Al/SiCp composites.The machining characteristics such as specific energy,tool wear and surface roughness were studied.The parameters such as volume fraction of SiC,cutting speed and feed rate were considered.Artificial neural networks(NN) was used to train and simulate the experimental data.Genetic algorithms(GA) was interfaced with ANN to optimize the machining conditions for the desired machining characteristics .Validation of optimized results was also performed by confirmation experiments. 相似文献