基于壳体典型特征的数控加工快速编程研究

基于特征进行编程是实现数控加工高效、快速编程的基础,针对这一问题,对基于壳体典型特征的数控加工快速编程进行了研究。通过分析壳体零件典型制造特征,将数控加工工步信息、刀具、切削参数通过用户化模板进行定制开发,形成壳体典型特征应用库,供不同用户进行数控加工编程时共享。在应用中,可以实现加工工艺信息的自动给定,通过简单设置便可完成数控加工编程,进而大幅提高数控加工编程效率。     

变型零件数控程序克隆和变异方法研究

为了提高变型零件的数控编程效率和品质,提出了对零件族数控程序母模板进行克隆和变异,使其快速派生出变型零件数控程序的编程方法。首先分析了数控程序母模板能被克隆和变异的必需条件,然后以母模型零件加工特征为数控加工单元进行几何数据的提取和加工参数的设置,构建了零件族数控程序母模板,并给出了由数控程序母模板克隆和变异出变型零件数控程序的方法和流程。最后以实例验证了该方法的可行性。     

变型零件数控程序快速生成系统研究

为提高变型零件数控程序的编制效率,提出了基于主模型零件数控程序主模板的快速编程方法,开发了相应的数控编程系统。首先,对主模型零件进行工艺分析,提取主模型零件加工特征的几何数据,并结合加工特征的加工工艺数据,构造主模型零件的数控程序主模板。主模型零件通过变型生成变型零件后,用变型零件的几何数据更新数控程序主模板中相应的几何数据,然后在工艺决策库的支持下,基于数控程序主模板自动生成该变型零件的数控程序,实现变型零件数控程序的数据驱动式生成。最后,通过实例验证了上述方法及其系统的可行性。     

链轮参数化编程技术与应用

通过对链轮几何特性分析,应用数控系统的变量编程功能,研究了链轮的参数化编程数控加工技术。系统地介绍了链轮的参数化编程方法,该方法编制的程序用于系列链轮的数控加工,程序简练,逻辑性强,调试运行简便,加工质量好、效率高,不需要专业软件及专用刀具,便于推广应用;并用实例进行了验证说明。本文对系列零件数控编程加工具有普遍意义。     

基于NX的数控加工模块设计与开发

传统零件数控加工工艺准备过程,从创建加工模型开始,到创建刀具,生成加工轨迹,最终生成数控代码,整个过程环节较多,不仅效率低下,质量也难以保证。因此,在分析现有零件特点的基础上,参考参数化建模思想,将零件分组建立加工模板,并通过对NX软件进行二次开发予以实现。工艺人员在用户界面上输入少量参数,可以快速生成加工模型,进而调用加工模板并选取现有刀具,生成加工刀路及数控代码,从而大幅提高工艺准备效率,稳定加工质量。     

基于知识熔接技术的锻模零件自动编程

以磨擦楔块锻模零件为加工对象,UGCAM为自动编程平台,应用数字化制造导航和制造模板,快速生成锻模零件的粗精加工刀具轨迹和数控加工程序。     

基于知识熔接技术的锻模零件自动编程

以磨擦楔块锻模零件为加工对象.UG OAM为自动编程平台,应用数字化制造导航和制造模板,快速生成锻模零件的粗精加工刀具轨迹和数控加工程序.     

Cimatron E环境下编程模板的应用

Cimatron E具有编程模板功能,该模板包含了加工的几何对象、加工策略和加工参数。针对特征相似的零件,本文提出了Cimatron E环境下基于编程模板的数控编程,以提高编程效率。最后以一个实例介绍了编程模板的创建与应用。     

一种过程与结构结合的数控知识建模研究

数控加工中的知识是指已有的参数、工艺和流程等加工经验的集合,数控加工知识类型繁多,应用背景复杂,不同零件的加工差异较大。本文建立了编程过程与工艺数据结构相结合的知识管理模型,模型构建过程中设计了通用的数控编程模板和知识体表达模板,通过模型的构建,实现了零件数控加工中知识背景的准确描述、知识载体的全面管理以及多类型的知识添加。最后,通过叶轮数控加工过程中的知识管理验证了模型的有效性。     

航空机电零件数控加工快速编程技术研究与开发

针对目前航空机电零件数控加工编程过程中存在的对编程人员编程经验和知识依赖度较高、编程效率低下、编程质量参差不齐等问题,研究了航空零件数控加工快速编程技术及系统,运用加工模板定制技术实现了编程知识和流程的固化封装,并基于NX OPEN/API开发了模板快速重用界面,用户依据界面引导即可快速完成数控加工编程,从而提高了编程的效率和质量稳定性。     

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.