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小口径非球面玻璃透镜模压成形 总被引:7,自引:0,他引:7
随着消费电子行业的增长和人们对轻便易携带的高性能产品的需求,非球面玻璃透镜的需求量持续增长。与传统冷加工方法相比,模压成形技术因具有低成本、批量生产的能力而成为一种更有前途的加工方法,尤其适合中小口径非球面透镜的生产。非球面玻璃透镜的模压成形技术是一项涉及玻璃材料、超精密模芯加工、镀膜、模压成形工艺及成仿真等诸多领域的综合技术。因此,有必要对其中影响成形质量的关键技术进行系统分析和深入研究,探讨模压成形技术现状和存在的问题。对光学玻璃的物理化学性质、主要构成成分、粘弹性、低熔点及环保的发展趋势、预形体的选择进行综合分析;对模芯材料的开发、非球面模芯的单点金刚石车削技术、纳米磨削技术、超精密研抛技术、复合加工技术、镀膜材料、镀膜技术做了详细介绍;阐述模压成形技术及仿真技术的研究现状及最新进展;并对未来发展趋势进行预测与展望。 相似文献
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Ik Soo Kang Jeong Suk Kim Yong Wie Seo 《Journal of Mechanical Science and Technology》2008,22(2):293-299
The analysis of the cutting force in micro end milling plays an important role in characterizing the cutting process, as the
tool wear and surface texture depend on the cutting forces. Because the depth of cut is larger than the tool edge radius in
conventional cutting, the effect of the tool edge radius can be ignored. However, in micro cutting, this radius has an influence
on the cutting mechanism. In this study, an analytical cutting force model for micro end milling is proposed for predicting
the cutting forces. The cutting force model, which considers the edge radius of the micro end mill, is simulated. The validity
is investigated through the newly developed tool dynamometer for the micro end milling process. The predicted cutting forces
were consistent with the experimental results. 相似文献
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Insoon Yang Min Soo Park Chong Nam Chu 《International Journal of Precision Engineering and Manufacturing》2009,10(2):5-10
In recent years, there has been a growing demand for micro holes. However, electrochemical machining has rarely been employed
in drilling these holes because of problems with electrolyte diffusion. In this research, a semi-cylindrical tool was used
as a tool electrode to increase the flow space of the electrolyte, and electrolyte diffusion was improved via the application
of ultrasonic vibrations. Micro holes with a specified diameter of 76 μm were drilled on a 304 stainless steel plate of 300μm
thickness. The proposed technique reduced both the machining time and the machining gap. 相似文献
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J. O. Aguilar J. M. Rodríguez-Lelis M. J. Arjona 《Journal of Mechanical Science and Technology》2009,23(4):1169-1174
In the triboadhesion process the coating material is passed through a rotating cotton mop and the substrate to be coated.
The cotton mop rotates at high velocity and exerts pressure on the surface of the substrate. The combined effect of pressure
and velocity of the coating mop on the substrate increases its temperature close to the melting point, allowing deposition
and diffusion of the coating material within the substrate. After it is deposited, its particles are embedded within the base
material forming a thin film composite. The amount of the coating material deposited on the substrate has its maximum at the
surface and then decreases as a function of the local temperature within the base material. Bearing this in mind, in the present
work, triboadhesion is employed to deposit iron oxide in a substrate of soda-lime glass, with the purpose of determining the
feasibility of using this technique for solar control coatings. It was found, through electronic scan microscopy, that a composite
material film is formed following the coating direction. Reflectance and transmittance tests were carried out on the glass
samples. A 20% difference was found in the visible spectral region (VIS), and a reduction between 10 and 20% in the Near Infrared
Region (NIR). These results showed that the triboadhesion is a promising technique for the application of thin films for solar
control or solar cells.
This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim
J. O Aguilar received a B.S. degree in Mechanical Engineering from ITCM in 1995. He then went on to receive his M.S degree from Cenidet
and his Ph. Degree from UNAM, in 1999 and 2005 respectively. Dr. Aguilar is currently a Professor at the Science and Engineering
Division at Universidad de Quintana Roo, Chetumal, Quintana Roo, México. Dr. Aguilar’s research interests are in the area
of solar control coatings and solar concentrating collectors.
J. M. Rodríguez-Lelis received a B.S. degree in Mechanical Engineering from ESIME (IPN) in 1984. He then went on to receive his M.S. and Ph.D.
degrees from Birmingham University (U.K.) in 1988 and 1992, respectively. Dr. Rodríguez-Lelis is currently a Professor at
the Mechanical Engineering Department at Cenidet in Cuernavaca, Morelos, México. Dr. Rodríguez-Lelis’s research interests
are in the area of tribology, surface enhancement by triboadhesión, turbomachinery and biomechanics.
M. J. Arjona received a B.S. degree in Energy Systems Engineering from Universidad de Quintana Roo in 2002. He then went on to receive
his M.S. degree from Cenidet in 2005. M.S. Arjona is currently a Professor at Universidad de la Ciénega de Michoacán, Sahuayo,
Michoacan. M.S. Arjona’s research interests are in the area of renewable energy 相似文献
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对超声振动辅助磨削加工中BK7光学玻璃材料表面及亚表面的微裂纹扩展过程中的交互作用进行研究,使用维氏金刚石压头进行了BK7光学玻璃二次印压实验来模拟超声振动作用影响下单颗磨粒对光学玻璃的反复印压作用,同时采用界面粘结法获得了不同印压载荷及印压距离下产生的压痕及微裂纹形态特征及分布情况。实验结果表明:在相同载荷加载情况下,第二次印压产生的亚表面中位裂纹扩展最大深度受到侧向裂纹影响减小了30μm,同时侧向裂纹闭合后在光学玻璃材料表面及内部产生破碎。基于压痕断裂力学理论,分析了准静态载荷作用下光学玻璃内部应力场的分布及应力场驱动下微裂纹的扩展机制,对超声振动效应影响下微裂纹扩展的交互作用进行研究。结果表明:磨削过程中使用轴向超声振动辅助,能够有效地降低光学玻璃材料亚表面裂纹的深度,改善亚表面及表面加工质量,同时促进了工件材料的去除。 相似文献
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During the machining process, cutting forces cause deformation of thin-walled parts and cutting tools because of their low rigidity. Such deformation can lead to undercut and may result in defective parts. Since there are various unexpected factors that affect cutting forces during the machining process, the error compensation of cutting force induced deformation is deemed to be a very difficult issue. In order to address this challenge, this article proposes a novel real time deformation error compensation method based on dynamic features. A dynamic feature model is established for the evaluation of feature rigidity as well as the association between geometric information and real time cutting force information. Then the deformations are calculated based on the dynamic feature model. Eventually, the machining error compensation for elastic deformation is realized based on Function Blocks. A thin-walled feature is used as an example to validate the proposed approach. Machining experiment results show that the errors of calculated deformation with the monitored deformation is less than 10%, and the thickness errors were between ?0.05 mm and +0.06 mm, which can well satisfy the accuracy requirement of structural parts by NC (Numerical Control) machining. 相似文献
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讨论了用人造多晶金刚右刀具(PCD)进行超精密切削加工的表面形貌,重点讨论了微观纹理特征。 相似文献
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由于具有刃口半径效应、径向刚度差、旋转速度高、切削稳定性差等特性,微径钻、铣刀具具有不同于常规尺度钻、铣刀具的失效特征。基于大量钻削和立铣削试验,在对常规尺度麻花钻、平头立铣刀的一般失效形式简要分析的基础上,研究了微径麻花钻和平头立铣刀的特殊失效形式及原因,提出了抑制微径钻、铣刀具失效的基本方法。结果表明:容屑空间堵塞、塑性变形、断齿是微径钻、铣刀具常见的失效形式;随着刀具直径减小、转速增高,整体断裂成为微径钻、铣刀具的最主要失效形式;改善材料切削性能、提高切削液作用效果、优选刀具材料及结构、优化切削工艺是抑制微径钻、铣刀具失效的根本措施。 相似文献
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提出了一种石英玻璃仿真模型的构建方法,并应用分子动力学(MD)仿真结合纳米压痕实验对石英玻璃进行了纳米级加工性能的研究。通过计算石英玻璃模型的密度和纳米硬度,验证了模型的准确性。对石英玻璃进行了纳米压痕实验,得到了压痕曲线并观察了纳米压痕形貌。最后,对纳米级压痕过程进行了仿真,通过计算配位数研究了损伤层的形成及扩展机理。计算得到的石英玻璃模型的纳米硬度约为9.7~10.7GPa,密度约为2.28g/cm3,与实际测量结果基本一致。仿真结果表明:石英玻璃有着稳定的塑性变形和少量的弹性变形,且存在压痕的尺寸效应。当压头压下时会形成大量的原子稠密区,失去原来共价键的强度,形成损伤层;而表面形貌主要是由于压头向两侧挤压原子和压头的黏附作用形成的。仿真和实验结果都表明石英玻璃比较适合超精密加工。 相似文献
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A. Lamikiz L. N. López de Lacalle O. Ocerin D. Díez E. Maidagan 《The International Journal of Advanced Manufacturing Technology》2008,37(1-2):122-139
In this work, a methodology for the estimation of the geometrical accuracy of five-axis milling centres is developed by using
the well-known formulation proposed by Denavit and Hartenberg. Five-axis milling centres are kinematically much more complex
than three-axis centres and, therefore, the consequences of parallelism and squareness errors between elements and joints
are not as easily calculated. In the method presented here, assembly errors are introduced as additional geometric parameters
in the element transformation matrices, resulting in the real transformation matrix for a real and, therefore, imperfect five-axis
milling machine. This matrix defines the real position of the tool in the absolute reference system. Three types of machine
structures have been studied, which are the most commonly built, assembled and sold: gantry with a two-rotary-axes head, transverse
column with a two-rotary-axes tilting table and, finally, a machine with a swivelling spindle and rotating plate. Each of
the elemental errors is described and the way to introduce them into the Denavit and Hartenberg matrices is proposed. Some
of the errors can be measured using the ISO standard procedures but others must be measured using special experiments, which
are described in Sect. 4 of this paper. Finally, a real application of the proposed methodology to improve the precision of
a multi-axis drilling operation is explained. 相似文献
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为提高五坐标数控加工刀具轨迹生成的精度和切削效率,通过特定机床结构运动建模,对自由曲面刀具轨迹规划中的走刀步长计算方法进行研究。针对刀具摆动与工作台转动类型的非正交结构五坐标机床,在建立机床运动传递关系的基础上,实现任意刀轴方位的机床各轴运动坐标分解,构建机床运动模型。基于此,分析切削误差产生机理,推导出非正交结构的机床实际运动误差估计公式。利用切削误差对比关系,迭代计算满足精度要求的最大走刀步长。算例表明,在相同的允许误差条件下,本文算法较之传统变步长方法,最大误差降低了37.01%,而平均步长相对于等步长方法,增加了8.91%,说明基于机床运动模型的走刀步长计算方法能够有效控制切削误差,并提高自由曲面五坐标加工的刀具轨迹质量。 相似文献
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F.-T. Weng M.-G. Her 《The International Journal of Advanced Manufacturing Technology》2002,19(4):266-270
The micro machining of copper plates by the electrical discharge machining (EDM) process is described. Tungsten carbide was
selected as the material for the electrode. Experiments were carried out on a conventional CNC-EDM machine to investigate
machining of micro holes, and micro slots. The results show that micro holes, and micro slots can be successfully processed
on a conventional CNC-EDM machine. To improve the productivity of micro parts using the EDM process, a batch production method
of micro EDM using multi-electrodes has been studied. A new technique for preparing multi-electrodes has been developed. Results
also show that the batch production of micro parts using EDM is feasible and that the batch production of micro parts using
EDM process with multi-electrodes is very effective. 相似文献