UGCAD/CAM在曲面零件造型及加工中的应用

UGCAD/CAM技术在数控加工领域中应用越来越广泛,近年来曲面零件在产品中占据比例越来越大,曲面的建模与加工均有一定的难度。以一复杂曲面零件为例,分析了UGCAD曲面建模的思路和难点,对曲面建模的主要步骤进行了说明;利用UGCAM模块对该零件进行了模拟加工,生成了刀轨,给出了加工程序单,说明了实际生产中注意的问题,对于曲面零件数控加工有一定的借鉴意义。     

基于UG的复杂曲面零件的数控加工

以一个复杂曲面零件模型为例,论述了UG CAO/CAM系统在数控加工中的应用过程：利用UG的建模模块对其进行曲面造型设计,并根据该零件结构特点进行工艺分析,使用UG的CAM加工模块设置加工参数实现自动编程,由程序后处理自动生成NC代码,最后将NC代码导入数控机床加工出实体零件,从而达到缩短编程时间,提高工作效率和编程质量的目的,有效地保证了零件的加工精度。     

CAD/CAM技术在飞机钣金件成型中的应用

文中针对飞机上的某一典型曲面类钣金零件,运用CAD/CAM技术,借助Master CAM V8.0软件完成了该曲面零件的实体造型以及制造该零件所需模具型面的数控加工程序设计和过程模拟.     

非线性空间曲面数控制造技术工艺研究

讨论了非线性空间曲面的CAD/CAM技术问题。通过典型非线性空间曲面零件加工工艺的分析,确定非线性空间曲面零件的加工工艺方案。利用U G软件创新使用组合建模法实现了非线性空间曲面的建模与编程,解决了非线性空间曲面CAD/CAM过程中的表面光洁度、工装等关键技术问题,利用UG后置处理的NC代码,在数控铣床上成功地加工出了合格的零件,并最终成功应用于企业,提高了产品加工精度,缩短了生产周期,取得良好的效果。     

异形面型芯数控加工与仿真研究

随着计算机技术的发展,先进的CAD/CAM软件技术在现代数控技术中的应用越来越广泛。通过运用UG这款先进的综合软件在模具数控加工方面的强大功能,结合典型曲面模具型芯零件,探索了其可变轴联动数控加工程序的一般方法,进行了复杂异形面型芯零件数控加工工艺设计,实现了复杂异形面型芯零件的粗加工、固定轴曲面轮廓半精加工、可变轴曲面轮廓精加工,同时进行了3D仿真验证,通过后处理可以生成实际可执行的可变轴数控加工程序,对实际生产具有较强的借鉴意义。     

CAM编程中刀具及工艺参数的确定

针对模具曲面的加工特点,分析了模具曲面数控铣削加工编程中刀具及工艺参数的选择对加工质量的影响,并结合实际介绍了在模具曲面数控加工中CAM编程时刀具及工艺参数的确定方法和原则。     

Master CAM在数控增量成形中的应用

介绍了金属板料数控增量成形的基本概念,根据金属圆锥形和直壁圆筒零件的形状特点,叙述了圆锥形和圆筒形等典型零件的一次成形和多次成形加工方式的选择方法,并给出了利用Master CAM曲面流线加工方式加工圆锥件和挖槽加工方式加工直壁圆筒件的工艺参数、工具头成形路径以及成形加工步骤.     

精密复杂零件数控加工在线检测与误差补偿技术研究

针对精密复杂零件数控加工离线检测误差大、效率低,在线检测尺寸、形状受限制等问题,建立了基于B样条曲面的确定性曲面回归模型,通过对回归模型残差空间独立性分析,将复杂零件的数控加工误差分解为系统误差和随机误差,通过修改数控代码,实现了精密复杂零件数控加工在线检测及误差补偿。为验证有效性,进行了大量试验,将试验结果与CMM检测结果对比,结果显示提出的在线检测及误差补偿方法行之有效,实现了精密复杂零件数控加工"加工-测量-补偿加工"的闭环制造。     

Master CAM在数控增量成形中的应用

介绍了金属板料数控增量成形的基本概念，根据金属圆锥形和直壁圆筒零件的形状特点，叙述了圆锥形和圆筒形等典型零件的一次成形和多次成形加工方式的选择方法，并给出了利用Master CAM曲面流线加工方式加工圆锥件和挖槽加工方式加工直壁圆筒件的工艺参数、工具头成形路径以及成形加工步骤。     

Master CAM在岛屿—凹槽类零件数控加工中的应用

阐述了用Master CAM软件对带岛屿的凹槽零件进行数控编程及加工的一般方法,针对加工工艺、数控编程、加工程序的模拟仿真以及后置处理等方面,进行了详细分析与介绍。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.