3D激光球杆仪伸缩导轨运动误差调整与测量

伸缩装置作为3D激光球杆仪的主要部件,其运动精度影响3D激光球杆仪俯仰角和偏摆角的测量值,为克服精密伸缩装置加工困难且成本较高的缺点,获得满足3D激光球杆仪测量精度的伸缩装置,提出以导轨为组件的伸缩导轨运动误差的调整和测量方法。该方法以直线度误差作为伸缩导轨运动精度的测量指标,采用自制准直仪进行伸缩导轨运动误差测量与调整。首先,通过标定实验和稳定性实验验证准直仪的测量可靠性。然后,以准直仪为测量基准进行导轨直线度误差测量,以导轨直线度调整方法为依据进行导轨直线度调整。最后,组装伸缩导轨,逐一运动各层导轨完成伸缩导轨运动误差测量;采用最小二乘法拟合得到上、下导轨与光轴在XR和YR平面的平行度误差,并计算上导轨和下导轨在XR和YR平面的平行度误差;调整上导轨角度,使上、下导轨平行,完成伸缩导轨运动误差调整。实验结果表明:上导轨X向和Y向直线度误差分别由44μm和439μm降到20μm和14μm,下导轨X向和Y向直线度误差分别由45μm和158μm降到25μm和37μm,伸缩导轨X向和Y向直线度误差分别由105μm和281μm降到47μm和48μm,达到提高精度的目的。     

提高导轨磨加工精度的有效方法

目前机床导轨一般都要求进行淬火处理,因此导轨的精加工就无法用刮削的方法,而只能靠磨削和研磨。我国机床厂的导轨磨精度一般不很高,对于精度要求(全长直线度)较高的大中型导轨的加工就是一个难题,我厂从实践中摸索出一种新的导轨磨削方法,效果显著,全长直线度可提高60%。 我厂加工的导轨长 2200 mm,淬火硬度RC 68,直线度 0.012 mm/全长, 0.005 mm/m,导轨间平行度0.01 mm。以往加工直线度只能达到 0.025～0.032 mm/全长, 0.006mm/m,平行度 0.008 mm(床身两侧向导轨),需再经手工研磨才能达到设计要求,效率极低。现采用这种新方法,工效一般…     

导轨磨床热变形问题的研究

热变形是影响机床精度稳定性的最主要因素。热变形是由于温度场分布在构件的各个方向上的差别引起的。以柔性化、自由化和解体化的设计理念解决导轨磨床热变形问题,使龙门导轨磨床的加工直线度达到0.001mm/m,直线度的稳定度为0.001 5mm/m,加工工件的表面粗糙度达到Ra0.4μm。     

静压导轨几何误差对运动直线度影响研究

为了提高机床的加工精度,研究液体静压导轨几何误差对运动直线度的影响规律。根据静压导轨对置油垫刚度和承载力的计算特征,建立导轨面形方程,对导轨进行运动误差分析,推导立柱运动直线度误差模型。以生产中常见的,因制造误差导致工作表面为凸型的闭式液体静压导轨为例,运用数学软件MATLAB对导轨运动误差进行曲线仿真,分析发现导轨的几何误差,如面形误差、立柱长度、导轨行程、及油垫对数对导轨运动的直线度有显著影响。最后通过实验所测的直线度曲线图和仿真进行对比,证明理论推导的正确性。     

使用短基准的超精密长导轨直线度误差测量方法

在超精密加工与检测技术中,高精度长导轨直线度误差的测量与补偿技术一直是一个研究重点。在系统研究现有各种导轨直线度误差测量方法的基础上,提出一种使用短基准的导轨直线度误差测量方法,将长导轨直线度误差的测量问题分解为具有一定重叠区域的数段较短导轨直线度误差的测量问题。直接利用超精密直线度物理基准测量各段导轨直线度误差,通过将各段导轨直线度误差拼接起来,重构出长导轨的直线度误差。利用空间坐标变换关系建立基于最小二乘法的直线度误差测量算法,以及相对机械运动误差对测量结果影响的数学模型,分析研究重叠区域二次采样点的匹配误差,以及测量误差、采样频率等因素对重叠区域长度选择的影响规律。对长550 mm的气浮导轨进行实际测量试验,仿真与测量试验表明上述方法简单实用,可操作性强。     

超精密机床热形变及其对运动精度的影响研究

超大口径超精密机床研制是大口径光学元件加工的必要基础,超大口径超精密机床在大行程、长工作周期的加工过程中,由于导轨发热引起的机床热形变将严重影响运动部件的直线度与光学元件的加工精度。利用ANSYS Workbench软件进行热-结构耦合仿真,对所设计的龙门式大口径磨削机床、5轴柔性气囊抛光机床进行了热形变分析,得到了导轨生热对机床整体热形变的影响规律。针对现有的磨削、抛光机床进行温度-直线度监测实验,探究了热形变对磨削机床所用液体静压导轨与抛光机床所用直线导轨运动直线度的影响规律,实际测量结果表明机床液体静压导轨的油膜生热对导轨运动直线度有较大影响。     

提高龙门镗铣床横梁导轨直线度的方法研究

横梁导轨是龙门镗铣床重要的支撑部件,其直线度精度直接影响工件的加工精度。针对龙门镗铣床长时间运行后横梁导轨直线度精度降低的问题,依托有限元技术,从横梁结构和现场装配工艺两个角度提出解决方案。从横梁结构上改进来提高抗弯刚度,从工艺上调整立柱的地脚螺栓处垫铁。通过横梁导轨变形量试验,结构和工艺都改进后的横梁导轨直线度提高超过50%,说明改进方法对提高横梁导轨直线度有明显作用。     

想想看

一、在机床上加工零件,大多数情况是只利用溜板全行程的一部分,所以对导轨局部直线度误差的控制,往往比全长更重要。例如导轨的误差曲线如图1所示,在 A-B 这一局部(通常取1m 长度)的直线度误差,按我国标准取△_1,而按国际标准(ISO1708—1978)取△_2     

花岗石在超精密加工机床中的应用

本文在简述了花岗石材料的特点之后,介绍了全部用花岗石材料制作的空气静压轴承和空气静压导轨,以及用花岗石空气轴承和花岗石空气静压导轨改造精密外圆磨床、制作超精密镗床、车床所达到的实际加工精度。     

基于激光干涉的长导轨直线度误差测量

介绍了一种基于激光干涉的长导轨直线度误差测量系统。由氦氖激光器产生激光光束,经准直后投射到被置于被测导轨上作为接收靶的楔形光学玻璃板上,产生干涉。将接收靶沿被测导轨移动,如果导轨有直线度误差,则接收靶过桥与导轨的接触点所形成的直线角度发生变化,导致干涉条纹发生移动,通过检测干涉条纹变化量就可以得到导轨的直线度误差。将光电传感器检测得到的干涉条纹移动量送入单片机系统处理,得到被测点相对于准直光束的偏移量。最后对系统进行了实测实验。实验表明:用该装置检测长度为50m的长导轨,直线度误差仅为623.103μm。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.