报警器外壳数控加工工艺设计

讲述了小批量产品加工的专用简易夹具设计以及薄壁件装夹加工方案,以报警器外壳产品数控加工重点突出其装夹工艺和加工工艺等关键问题,对薄壁件的加工设计了专用的夹具,这些夹具能较好的保证加工精度和稳定性,也较大的提高了加工效率,所以在加工薄壁零件的时候专用夹具的设计是非常有必要.     

一种半球形薄壁零件的加工夹具设计

半球形薄壁类零件由于装夹不便、加工过程中易变形等因素使得加工困难,加工精度难以保证。文中对该类型零件的结构特点、难点及加工工艺进行了分析,设计了一种组合夹具对该类零件进行加工。该夹具拆卸简单、装夹方便,很好地解决了半球形薄壁类零件装夹不便及加工过程中易变形的问题,提高了生产效率,保证了加工精度。     

薄壁管零件数控车削加工工艺研究

以薄壁零件"变形管"为研究对象,研究薄壁零件的数控车削加工工艺,并对工装夹具进行优化设计,改善了薄壁管零件的加工变形问题,减少了工件装夹、定位时间,提高了加工效率和精度,使产品的工艺性和经济性得到显著的提高。     

薄壁类零件装夹夹具设计方法

夹具设计的众多环节中,薄壁类零件装夹与加工变形是最为重要的内容,应引起相关人员的足够重视。按照薄壁类零件装夹的基本特征,可设计一种柔性夹具零件。由于这种类型的夹具具有一定的支撑机构,可有效防止薄壁零件加工中的变形等异常现象发生,使所加工出的零件满足相关要求,同时提高企业的生产效率。     

面向薄壁零件加工变形与振动控制的智能装夹技术研究进展

薄壁零件由于其弱刚性导致的切削加工变形与振动极大地影响着产品的最终质量.合理的装夹能够控制加工变形与振动,有效提升薄壁零件的加工稳定性.随着新型传感与控制算法的发展,现代夹具逐渐向智能化方向发展,集成夹紧力控制、变形补偿、实时监测、动态反馈调整等功能于一体的智能夹具应运而生,并成为学术界和工业界的研究热点.本文梳理了薄壁零件装夹方案优化方法及其加工辅助支撑技术、综述了当前关于智能夹具架构、具体应用及其控制策略的国内外研究现状,最后总结了当前装夹方案优化及智能夹具研究方面所存在的问题并提出下一步的研究方向.     

电火花多功能夹具设计与研究

介绍了一套适合电火花加工的夹具，不但可以实现不同尺寸薄壁零件的快速而准确地定位和装夹，还能通过旋转摇柄，对小型的矩形零件和弧形零件实现定位和装夹。在整个设计中，夹具采用了由下向上的冷却方式，对电火花零件的加工质量的提高也能起到较好的促进作用。     

薄壁圆筒零件的加工工艺

针对薄壁圆筒零件在车削加工时容易产生振动及变形的问题,分析原因,并改进装夹方式,优化夹具。在此基础上,提出薄壁圆筒零件的加工工艺,提高加工效率和产品合格率,为企业节约成本。     

四轴铣削薄壁回转类零件辅助工装设计

针对薄壁回转类零件刚性差,数控铣削过程中在夹具夹紧力和切削力的作用下容易产生加工变形,严重影响加工精度和表面质量等问题,分析和阐述了制约薄壁回转类零件加工精度的因素,设计并制作了针对某产品滤清器法兰的四轴装夹辅助工装,并对工装装夹位置布局和夹紧力进行了优化,有效地降低了由于装夹不当所引起的零件变形程度,提高了零件的加工精度。     

用于薄壁件加工的柔性夹具研究现状

对相变材料柔性夹具进行了系统介绍,并提出一种新型的柔性夹具,该夹具能真正实现柔性装夹,即一套夹具能装夹一定尺寸范围内任意形状及尺寸的零件,并有效克服薄壁件在加工过程中的装夹变形,从而保证零件的加工质量。     

汽车空调系统上盖体零件专用夹具设计

某工厂生产的汽车空调系统上盖体零件属于薄壁套筒件,形状不规则,在铣削加工过程中采用通用夹具进行定位加工时,费时费力,零件的质量难以保证.为了解决上盖体零件难以定位装夹的难题,为上盖体零件设计了一种专用铣床夹具.该夹具具有装夹效率高、工作可靠、体积小以及成本低等优点.实际应用显示:使用该夹具后,零件的合格率提高了35％,加工效率提升了37.5％,满足了该零件大批量生产的需要,对同类工件专用夹具的设计具有一定的参考价值.     

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.