抛光工艺参数研究

采用单因素实验法,获得较优的抛光工艺参数,以控制抛光工艺参数来达到各种零件表面粗糙度值的要求.论述的抛光工艺参数适用于曲面、特种材料的精密零件抛光.     

抛光工艺参数的试验研究

采用单因素实验法 ,获得较优的抛光工艺参数 ,以控制抛光工艺参数来达到各种零件表面粗糙度值的要求 ,是行之有效的方法。论述的抛光工艺参数适用于曲面、特种材料的精密零件抛光。     

特种材料HR-1挤压珩磨工艺研究

挤压珩磨是一种利用半流体磨料流反复挤压被加工表面而遮列研抛、去毛刺目的的新技术.针对抗氢钢(HR-1)的抛光难题进行珩磨加工实验,并采用扫描电镜分析表面形貌的方法及挂水检测法对抛光后零件的洁净度进行对比分析,结果表明:采用挤压珩磨抛光回转类零件外形曲面,其表面粗糙度能稳定地由Ra1.6 μm达到Ra≤0.1 μm,且磨料组成对表面洁净度无影响.挤压珩磨抛光后零件的表面粗糙皮与工件原姑表面粗棱度有关,原始表面粗糙皮越高,挤压珩磨抛光后表面粗糙度越高.更换磨料可实现用粗、精抛的挤压珩磨抛光方法替代手工抛光.     

应用于模具自由曲面的新型气囊抛光技术

为提高模具自由曲面抛光的效率和品质,提出一种基于柔性抛光理念的新型气囊抛光技术。建立相应的机器人抛光系统,研究旋转型膨胀气囊抛光工具及抛光过程中各因素对抛光表面粗糙度的影响。对气囊抛光工具的位置和姿态控制问题以及抛光工具,以一定下陷深度和倾斜角度与被抛工件接触时的接触区域的相关特性进行分析。在机器人抛光系统上进行抛光正交试验和试验数据分析,获取表面粗糙度的不同影响因数的最优参数组合,试验中被抛光曲面平均表面粗糙度达到了0.007 μm。研究结果表明,气囊抛光技术可实现抛光工具与被抛光工件的大面积柔性接触,通过气囊内部气压的调节和机器人抛光系统对抛光工具的运动轨迹和姿态的精确控制,可有效地提升自由曲面抛光的品质和效率。     

三维振动强化抛光加工实验

三维振动强化抛光加工实验在超高速空气动力实验中 ,使用了大量由不锈钢制作的测试模型 ,形状均为异形曲面的空心零件 ,壁厚仅为 1 mm,其表面粗糙度要求为 Ra1 .6～ 0 .4μm,且对其疲劳强度也有很高的要求。采用传统加工方法加工 ,易发生变形 ,表面粗糙度、抗疲劳强度也很难达到要求。为此 ,采用了三维振动强化抛光加工 ,取得了较好的效果。1 .三维振动强化抛光加工原理和装置三维振动强化抛光工艺是集振动切削抛光与抛丸强化加工复合而成的工艺方法。在加工过程中 ,由电动激振器产生振动 ,使研磨介质与加工零件之间产生有一定振幅、振频的…     

曲面铝合金锤击平整技术研究

以曲面铝合金为例,利用工业机器人锤击的方式对曲面类零件表面进行平整,并探究各锤击工艺参数对其表面的粗糙度、硬度及表面形貌的影响.将锤击装置装夹到工业机器人上,控制工业机器人以矩形光栅式运动路径对曲面铝合金表面进行锤击加工,并对锤击后表面的粗糙度、硬度及表面形貌进行测量观察.结果表明:经锤击加工后的铝合金表面粗糙度可达0...     

基于环形磁场励磁的多工位磁流变抛光方法

提出一种基于环形磁场励磁的商用磁流变抛光方法,可满足工业化大批量生产需求。通过设计环形磁场的电磁铁,进行三维有限元仿真分析,配合既公转、自转又摇摆的多工位抛光头,搭建环形磁场磁流变抛光装置。利用该平台分别对表面粗糙度为0. 2μm的铝合金和不锈钢手表框曲面进行磁流变抛光试验,结果表明该方法可以同时对多个工件的曲面进行抛光,抛光后两者的表面粗糙度分别提高到0. 05μm和0. 025μm,从而验证该加工方法进行精密抛光的可行性。     

软体磨具新技术

零件曲表面的磨光,抛光技术是精密加工技术领域的难题,传统的磨具难以直接对不规则的曲面进行加工。作者研究的软磨具,是一种体内均匀含磨料的新型高分子复合材料、磨料和抛光粉为加工要素,聚氨酯基网链状高分子材料为连接剂并为抛光要素。新型软磨具为三维柔软的弹性体,能适应任意曲率的零件（金属或非金属）表面的磨光和抛光要求。本文包括新型软磨具的生成理论,制造技术和曲面零件抛光的工艺性能试验研究。     

复杂曲面零件超精密加工方法的研究进展

超精密加工技术是降低工件表面粗糙度、去除损伤层,获得高形状精度、表面精度和表面完整性的终加工手段。复杂曲面零件的广泛应用和精度要求的不断提高,取决于复杂曲面零件的超精密加工技术。概述了复杂曲面零件的超精密成形加工、超精密抛光等加工方法,分析各种典型加工方法和材料去除机理,从加工精度、工具与曲面吻合度、加工效率与成本、环境友好性等方面对几种复杂曲面超精密加工方法进行比较。对复杂曲面零件超精密加工技术的发展趋势进行预测。     

精密零件手动抛光

本文论述的精密零件手动抛光工艺适用于小尺寸、曲面、特种材料的精密零件抛光,如:1Cr18Ni9Ti、00Cr17Ni14Mo2、4J29、4J33、Mo1等。 由于我院科研产品的需要,经常加工形状复杂,外形尺寸小,表面粗糙度值要求R_a≤0.1μm的零件。零件抛光时,不允许使用任何切削液。我们采用单因素影响法,经过多次实验,获得了较优的抛光工艺参数,使特种材料的小型曲面零件的表     

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.     

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....     

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。     

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.