共查询到18条相似文献,搜索用时 343 毫秒
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光学器件和光学测量系统的关键部件主要通过超精密加工制造。铝合金具有很多优势,通常用于光子产业。光学领域对铝合金使用和需求的不断增加,促进了在铸造过程中采用快速凝固技术对铝合金等级重新改良的发展。优异的微观结构和改进的机械和物理性能是新型铝合金等级的特点。目前主要问题在于采用金刚石车削时,由于在切削性方面缺乏对铝合金性能的充分研究,导致机械加工数据库非常有限。本文通过改变金刚石的切削参数,测量切齿安装距超过4km时金刚石刀具的磨损,研究了快速凝固铝合金RSA 905的切削性能。改变的机械加工参数为切削速度、进给速度和切削深度。结果表明切削速度对金刚石刀具的磨损影响最大。主轴转速为500rpm、进给速度为25mm/min、切削深度为15μm时,刀具磨损达到最大值12.2μm;主轴转速为1750rpm、进给速度为5mm/min、切削深度为5μm时,刀具磨损达到最小值2.45μm。通常,较高的切削速度、较低的进给速度和较短的切削深度的组合可以减少金刚石刀具磨损。建立了模型统计以分析金刚石刀具磨损。通过该模型可以生成磨损图,从而确定切削参数产生最小磨损的区域。结果证明,快速凝固铝是更好的选择,为机械工程师使用这种材料提供了参考。 相似文献
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螺旋桨鸣音的混沌动力特性研究 总被引:2,自引:0,他引:2
利用混沌动力学方法研究螺旋桨鸣音信号时间序列,估计时间序列的相空间重构最佳参数,并提出其具有混沌动力特性,分析了系统拓扑维数的边界和生成系统所必须独立变量的个数,还计算分析了重构相空间中吸引子轨迹随时间演化的发散情况。分析计算结果表明:螺旋桨鸣音信号时间序列可以选取最佳延迟时间tD=1、最小嵌入维数dE=8进行相空间重构,其混沌吸引子的关联维数为5.1579、最大Lyapunov指数为0.0771,此研究结果可以为螺旋桨鸣音现象的进一步研究提供理论基础。 相似文献
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基于Lorenz,Rssler和H啨non三种典型的奇怪吸引子,全面分析了GrassbergerProcaccia(缩写GP)算法,详细讨论了采样数据量、延迟时间、重构相空间维数和线性区长度等参数对计算关联维数和Kolmogorov熵的影响,结果表明这些关键参数是相互关联的.通过分析关联积分谱的变化趋势,发现延迟时间与重构相空间维数对连续动力系统和离散动力系统的作用效果是不同的,且选择最佳延迟时间对计算关联维数的意义不大.指出了实际中应用GP算法应注意的问题
关键词:
奇怪吸引子
GrassbergerProcaccia算法
关联维数
Kolmogorov熵 相似文献
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采用单点金刚石切削技术,通过合理的刀具设计、夹具设计及工艺过程设计,确定了加工工艺参数,完成了厚度几μm至几十μm的无氧铜多台阶靶的制备。通过触针式轮廓仪,台阶仪,白光干涉仪对表面轮廓及粗糙度进行了测量。结果表明:通过单点金刚石切削技术加工成形的铜多台阶靶,各台阶表面均方根粗糙度小于50 nm,工件表面轮廓平直,台阶垂直度较好。采用阿基米德原理对材料密度进行测量,加工成形后密度为(8.945±0.074) g/cm3,接近材料理论密度。 相似文献
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针对采用单点金刚石超精加工的KDP晶体光学表面,研究了切削参数对微观形貌频率特征的影响。通过功率谱密度获得表面轮廓频率分布,并用连续小波重构加工过程中随切削用量变化的微观轮廓频率特征。结果表明:切削参数对微观形貌的影响具体表现在实际频率特征上,中频特征波长及幅值反映了切深及转速变化,随切深及转速增加,幅值变大;低频特征反映了进给量变化,随着进给量变小,频率及幅值变小;高频特征是加工过程中振动及材料各向异性的具体表现。 相似文献
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Morphology and distribution of subsurface damage in optical fused silica parts: Bound-abrasive grinding 总被引:1,自引:0,他引:1
Yaguo LiHaibo Li Jing HouXiangyang Lei Xianhua ChenZhigang Yuan Zhaozhou GuoJian Wang Yinbiao GuoQiao Xu 《Applied Surface Science》2011,257(6):2066-2073
The depth and morphology of subsurface damage (SSD) in fused silica samples ground with diamond grinding wheels were investigated. The factors possibly influencing the SSD depth of ground samples were examined. The results demonstrate that the SSD depth is most responsive to diamond grit size while the processing parameters (i.e. depth of cut, feed rate, and wheel peripheral speed) have marginal effects on the SSD depth. The SSD depth decreases with the abrasive/grit size of diamond wheels and slightly diminishes with the decrease of cutting depth but little influenced by feeding rate and wheel speed. The morphology inspection shows that the density of subsurface cracks in ground fused silica samples decays exponentially with the depth from the ground surface into the bulk and the cracks vanish at a certain depth that depends on the mechanical and physical properties of samples and diamond abrasives/grits. 相似文献
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具有材料理论密度的金属薄膜对于材料高压状态方程(EOS)研究而言具有重要的意义。本文提出采用金刚石车削技术,利用超精密金刚石车床、金刚石圆弧刀具及真空吸附夹持技术,对纯铝和无氧铜进行端面车削,完成了EOS实验用铝薄膜和铜薄膜的车削加工,实现了薄膜密度接近材料理论密度。精加工工艺参数为:进给量0.001 mm/r,主轴转速3000 r/min,切削深度1 μm。采用Form Talysurf series 2型触针式轮廓仪进行测量,结果表明:铝薄膜、铜薄膜厚度可以达到小于10 μm水平,表面均方根粗糙度小于5 nm,原始最大轮廓峰-谷高度小于50 nm,厚度一致性好于99%。 相似文献
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Zhou Zhimin Zhang Yuanliang Li Xiaoyan Zhou Huiyuan Sun Baoyuan 《Acoustical Physics》2011,57(1):114-120
This paper presents an investigation of the process factors affecting the surface roughness in ultra-precision diamond turning
with ultrasonic vibration. Stainless steel was turned by diamond tools with ultrasonic vibration applied in the feed direction
with an auto-resonant control system. Surface roughness was measured and compared along with the change of the cutting parameters.
The relation curves between the cutting parameters and surface roughness were achieved by comparing the experimental results
with different cutting speeds, feed rates, cutting depths. Experimental results indicate that cutting parameters have an obvious
effect on the surface roughness. The conclusions are draw in given conditions, the smaller amplitude of the vibration, the
worse the surface quality and the higher vibrating frequency, the better surface quality, and the deeper the cutting depth
and the more the feed rate, the worse the surface quality. Among these parameters, the feed rate was the most important factor
on surface quality. 相似文献
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采用超精密车削技术加工微尺度正弦波调制曲面微结构,解决了尖刃金刚石刀具刃磨和刀具对中等关键技术,研究了进给量、背吃刀量和主轴转速等主要切削参数对铜模板表面粗糙度的影响规律。加工出波长为(20~150)m0.5 m﹑峰谷高度差为(0.2~20)m0.1 m的带正弦波调制曲面。采用原子力显微镜对模板表面轮廓扫描,在20 m20 m的范围内,其表面粗糙度均方根值小于10 nm。将正弦波调制曲面测量结果与理论轮廓进行比较,采用最小二乘寻优算法评定轮廓误差。完成了曲面轮廓的功率谱表征,利用加工的曲面微结构制备了平面调制靶,实现正弦波调制曲面轮廓的精确转移。 相似文献
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In metal cutting machining, major factors that affect the cutting tool life are machine tool vibrations, tool tip/chip temperature and surface roughness along with machining parameters like cutting speed, feed rate, depth of cut, tool geometry, etc., so it becomes important for the manufacturing industry to find the suitable levels of process parameters for obtaining maintaining tool life. Heat generation in cutting was always a main topic to be studied in machining. Recent advancement in signal processing and information technology has resulted in the use of multiple sensors for development of the effective monitoring of tool condition monitoring systems with improved accuracy. From a process improvement point of view, it is definitely more advantageous to proactively monitor quality directly in the process instead of the product, so that the consequences of a defective part can be minimized or even eliminated.In the present work, a real time process monitoring method is explored using multiple sensors. It focuses on the development of a test bed for monitoring the tool condition in turning of AISI 316L steel by using both coated and uncoated carbide inserts. Proposed tool condition monitoring (TCM) is evaluated in the high speed turning using multiple sensors such as Laser Doppler vibrometer and infrared thermography technique. The results indicate the feasibility of using the dominant frequency of the vibration signals for the monitoring of high speed turning operations along with temperatures gradient. A possible correlation is identified in both regular and irregular cutting tool wear. While cutting speed and feed rate proved to be influential parameter on the depicted temperatures and depth of cut to be less influential. Generally, it is observed that lower heat and temperatures are generated when coated inserts are employed. It is found that cutting temperatures are gradually increased as edge wear and deformation developed. 相似文献