Model development for the prediction of surface topography generated by ball-end mills taking into account the tool parallel axis offset. Experimental validation

This paper presents a model for the topography prediction of ball-end milled surfaces, considering the tool parallel axis offset. First, the equations of cutting edge trajectories and the envelope equation of the material swept by the tool are derived. Later, the trajectories are cut by planes perpendicular to the feed direction obtaining a set of transcendental equations that are solved by transforming them to polynomial equations through Chebyshev expansions. This procedure presents the advantage on previous models in literature of not requiring any starting point to achieve the solution. Finally, experimental results are presented and compared to the model predictions.     

Thermal processing induced plastic deformation in GaAs wafers

Different types of dislocation bundles were identified in the (001) GaAs substrates of III–V heterostructures. Comparisons of scanning infrared polariscopy images and X-ray transmission topograms showed a one to one correlation of stripes of reduced residual shear strain and dislocation bundles of the majority type. Visible-light interferometry and Makyoh topography, on the other hand, showed a slip-line distribution that is in correspondence to the distribution of dislocation bundles of the minority type(s). A new model for the plastic deformation of circular GaAs wafers during thermal processing is briefly outlined and its good agreement with the main experimental results demonstrated.     

YHZ-1型遥控振动式海底取样钻机

YHZ-1型遥控振动式海底取样钻机包括船上设备和海下钻机2大部分,应用了计算机技术和现代电子测控技术.介绍了其结构原理、性能特点、技术参数及电气系统.     

带再生反馈的柔性立铣刀铣削过程模型

精确合理的铣削过程模型是研究铣削加工表面形貌的关键。首先根据线性弹性体基本假设,将铣削过程中刀杆所受的力和产生的变形均分解为动、静两部分;然后运用微分几何理论,考虑实际切削过程中的再生效应,导出动态铣削力集度表达式,进而建立刀杆的动态变形模型,并构造出一套与之相应的高效快速数值仿真算法,同时还给出刀杆静态变形量的计算方法;最后通过仿真实例说明该模型的合理性。     

表面三维微观形貌检测技术及其发展

从表面特征衡量的角度阐述三维参数评定的客观性及合理性,强调三维微观形貌测量的重要民生。介绍当前表面三维微观形貌检测的多种测量方法及其特点,并阐述该测量技术的发展及趋势,提出表面形貌检测应从简单过程检测的角度扩展到完成工艺优化角色的思想。     

3D simulations of the experimental signal measured in near-field optical microscopy

We present three-dimensional simulations of the image formation process in near-field optical microscopy. Our calculations take into account the different components of a realistic experiment: an extended metal coated tip, a subwavelength sample and its substrate. We investigate all possible detection (transmitted, reflected and collected field) and scanning (constant height, constant gap) modes. Our results emphasize the strong influence of the tip motion on the experimental signal. They also show that it is possible, by controlling the polarization of both the illumination and the detected field, to strongly reduce these artefacts.     

界面形貌对热障涂层界面残余应力影响的数值模拟

利用有限元方法 ,对热障涂层热循环降温过程中产生的残余应力进行了数值模拟 ,研究了有尖点和无尖点正弦波形微坑以及矩形微坑对界面残余应力的影响。结果表明 ,微坑形状不同 ,界面上残余应力的大小、性质与分布也不同 ;微坑的形状变化和尖点的出现 ,将会使该处的应力发生突变 ,不利于增强界面结合强度。因此 ,从对热障涂层界面残余应力的影响角度看 ,无尖点的正弦波形微坑既优于有尖点微坑也优于矩形微坑     

热障涂层界面微结构尺寸与残余应力关系的数值模拟

利用有限元方法,对热障涂层热循环降温过程中产生的残余应力进行了数值模拟。以无尖点正弦波形界面形貌为对象,研究了其微结构尺寸（包括微坑间距,宽度和深度）对平行和垂直于界面的残余应力最大值SMX和SMY的影响规律。结果表明,在本文所给定的尺度范围内,微结构尺寸为SMX和SMY均有影响,但对SMY的影响要更为显著;在微坑深度,宽度和间距等3个微结构尺寸参数中,微坑深度对界面残余应力的影响最大。     

Accuracy of replica materials when measuring engineering surfaces

This paper presents a comprehensive study of three different materials used for surface roughness replication on five different types of machined surfaces. Steel sheets (electron beam texturing and shot blasted texturing), a cylinder liner, a crankshaft and a face-ground surface. The three different replica materials used were Araldite, Microset and Technovit. The surfaces were measured with the non-contact WYKO interference instrument, zoomed to relocate the same area on the original and on the replicas. Finally, three-dimensional surface parameters were calculated to compare each replica with the original surface.The results show that all materials are possible to use in order to measure and calculate three-dimensional surface parameters, but they have some peculiarities. The three replicas all show good accuracy on all surfaces, with deviations <10%, except for the crankshaft. Only Araldite and Technovit occasionally show S_z values that are >10% too high due to a small number of pores in these materials. Replicas in the Microset material in general show somewhat lower parameter values than the original surface. All replicas showed some problems on the fine-ground crankshaft with an enlargement of the fine structure, resulting in parameters ca 20% too large. The deviation of surface parameters on repeated measuring on replicas is considerably larger than on repeated measuring of the original surfaces.