高速切削刀具材料及其应用

高速切削能加工出精度较高的零件,还能降低加工成本。高速切削技术已经成为最有前途的先进制造技术之一,其应用领域正在持续扩展。高速切削技术是随着刀具技术如刀具材料等的发展而发展起来的。介绍了高速切削中所使用的金刚石、立方氮化硼、陶瓷、金属陶瓷和涂层刀具等的性能、适用范围和发展方向,并介绍涂层刀具、超细晶粒硬质合金和高速钢刀具的制备技术,以促进高速切削技术的推广应用。     

金刚石涂层刀具高速铣削石墨的磨损形态与破损机理

通过对比切削试验,分析了金刚石涂层刀具高速铣削石墨时的磨损形态与过程,论述了金刚石涂层刀具的破损原因与失效机理,为金刚石涂层刀具在高速切削领域的推广应用提供了实用的依据。     

金刚石涂层刀具在干式切削中的性能分析

介绍了干式切削加工技术的优点及发展趋势,分析了干式切削刀具技术及金刚石涂层刀具的性能特点.通过铝硅合金的干式切削试验,研究了金刚石涂层刀具的干式切削加工特性.经试验表明,金刚石涂层刀具正常磨损阶段,工件表面粗糙度非常稳定;刀具损坏以涂层脱落为主,刀具寿命取决于涂层与机体的结合强度;进给量对工件表面粗糙度影响最大,如果进给量合适,可以保证金刚石涂层刀具在高速下具有良好的干式切削性能.     

CIP石墨高速加工关键技术及应用研究进展

各向同性CIP石墨因具有诸多优点而广泛应用于热场、电火花放电、光伏发电等领域,但切削加工时易变形和崩碎断裂、刀具磨损严重且加工精度低。综述已有的各向同性石墨高速切削研究成果,包括石墨微细孔钻削加工、高速加工和切削模型,分析石墨高速铣削的切削力和切削温度特征,得到石墨高速加工硬质合金和CVD金刚石涂层刀具的磨损过程和机理。结合相关研究成果的应用,制定了典型石墨薄壁件铣削加工策略和石墨电极EDM放电加工关键工艺技术,成功加工0. 15mm、高度15mm的微细针状石墨电极和薄壁状微细渐开线薄片,实现了石墨精密切削加工。     

金刚石涂层刀具铣削高硅铝合金的性能研究

选用未涂层、TiAlN涂层及金刚石涂层整体硬质合金两刃平头立铣刀,在相同切削参数下进行高硅铝合金的高速铣削加工试验。试验结果表明:金刚石涂层铣刀具有良好的耐磨性,在切削过程中刀刃磨损均匀缓慢,刀具使用寿命长,加工表面粗糙度值稳定性好,是铣削高硅铝合金的理想刀具。     

晶粒细化对金刚石涂层刀具切削性能的影响

金刚石涂层具有高硬度、低摩擦系数、高耐磨性和高导热性能。本文着重介绍了金刚石涂层刀具的发展动向及现状,并通过金刚石涂层刀具的切削试验表明了金刚石涂层刀具的使用寿命明显高于未涂层的硬质合金刀具,采用金刚石涂层刀具进行切削可以获得更高的表面加工质量和生产率。     

高速切削刀具材料的发展应用研究

发展高速切削是现代切削加工技术的重要趋势,高速切削刀具材料也是影响制造业发展的重要因素.介绍了高速切削刀具材料的特点,具体分析了高速切削加工常见刀具材料硬质合金、陶瓷、金刚石类材料的特性、发展及其应用,并对未来高速切削刀具材料的发展趋势进行了展望.细晶和表面涂层硬质合金材料、氧化铝各系列陶瓷材料以及立方氮化硼(CBN)金刚石类材料是未来高速切削刀具材料发展的方向.根据高速切削刀具材料的特点,应用场合及其发展状态,对其未来的发展提出一些建议.     

超硬涂层刀具

涂层刀具的出现是刀具发展史上的一个重要里程碑,解决了刀具材料硬度和耐磨性愈高强度和韧性愈低的矛盾.金刚石等超硬涂层刀具的问世,是近几年来涂层技术发展的一个重大成就.它与新一代高速机床及工具系统相结合,使高速切削、干切削和硬加工技术得到迅速发展,并使切削效率和零件的加工质量的提高达到一个新的水平     

CVD金刚石薄膜刀具加工SiC_p/Al复合材料时的切削磨损研究

通过用CVD金刚石薄膜涂层刀具切削加工SiC颗粒增强铝基复合材料的试验 ,研究了切削参数、刀具材料、刀具几何参数和工件材料对CVD金刚石薄膜涂层刀具磨损的影响规律 ,同时研究了SiCp/Al复合材料的切削加工性能。     

CVD金刚石薄膜刀具加工SiCp／Al复合材料的切削磨损研究

通过用CVD金刚石薄膜涂层刀具切削加工SiC颗粒增强基复合材料的试验,研究了切削参数、刀具材料、刀具几何参数和工件材料对CVD金刚石薄膜涂层刀具磨损的影响规律,同时研究SiCp/Al复合材料的切削加工性能。     

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.