螺旋槽丝锥的改进设计与加工方法

为了改进切削不同材料时的丝锥结构,提出了由四段相切圆弧构成的丝锥螺旋槽,切削圆弧的偏移控制丝锥的切削前角,卷屑圆弧控制切屑的卷屑与断屑,容屑圆弧控制容屑空间的大小,刃背圆弧控制丝锥刃背后角的大小,丝锥螺旋槽数、前角、后角、芯径和刃带可根据不同的被加工材料选取。此槽形容屑空间大,尤其适合轻合金材料的加工,槽与背可一次成形加工。加工螺旋槽时,由于螺旋槽导程以丝锥最大外圆尺寸计算,会产生干涉现象,因此根据丝锥螺旋槽曲线应用神经网络与数据建模方法,拟合出丝锥槽铣刀刃形曲线及砂轮刃形曲线,以此曲线制作出螺旋槽铣刀和螺旋槽砂轮刃形,可精确铣削和磨削丝锥螺旋槽形。     

加工专用丝锥容屑槽刀具的选用

各种规格的通用丝锥的容屑槽一般采用定型的标准槽刀加工。为了适应加工各种不同材料的需要，对各种专用丝锥的需求不断增加。这些专用丝锥的前角等参数与通用丝锥相比更加细化。如下表所示为日本OSG株式会社针对不同加工材料推荐的丝锥前角值。由于专用丝锥生产批量小、交货期短，为了降低加工成本，缩短交货期，应尽可能用标准槽刀来加工专用丝锥容屑槽。这就需要对刀具的加工可行性进行验证，通常是采用手工绘制放大图和试切的方法进行验证，这种方法费时费力、准确性差、浪费材料。本文推导出加工两圆弧一直线型通用槽形选用槽刀的计…     

加工丝锥沟槽铣刀的成形铲刀廓形角的修整

<正> 一、问题的提出在手用丝锥国家标准GB3464—83中未对丝锥容屑槽的形状和槽形角提出明确的要求,这样制造厂方可在保证丝锥具有良好的切削性能和容屑槽连接圆滑的前提下有更多的设计和工艺上的机动性。为了制造方便,必须提供具体的参考数据。以M10为例,通常取前角γ=10°±2°,刃背宽度F=4.1~(-0.40),锥心直径d=4~(-4),容屑槽螺旋角ω=46～47°,槽数z=3,但在实际加工容屑槽的过程中,经常     

应用UG NX7.5建模技术优化丝锥容屑槽设计

正丝锥容屑槽形的传统设计方法是运用平面几何和解析几析方法求解出槽形两圆弧半径及圆心坐标,然后用几何做图法画出容屑槽截形轮廓。应用SIEMENS公司的UG NX7.5中的参数化建模技术,可用基于特征和约束的参数化驱动方法建立三维槽形优化丝锥库。在参数化表中简单地改变丝锥的大径D、螺距P、前角r、刃瓣宽度F、芯圆直径D1和槽     

楔形防松螺纹丝锥容屑槽的设计

丝锥容屑槽槽形是影响螺纹质量和丝锥寿命的重要因素,文中针对楔形防松螺纹丝锥,利用SolidWorks的尺寸驱动功能完成容屑槽设计,并同时得到三维模型,设计效率大大提高.通过总结丝锥使用经验,对槽形的关键结构参数提出了合理的选择方案.     

丝锥容屑槽及其成形铣刀、铲刀、样板的计算机辅助设计

我国各丝锥制造厂普遍采用铲齿成形铣刀加工丝锥容屑槽.对前角较大的成形铣刀,传统的设计方法存在不容忽略的误差,且不便于检验.本文介绍的计算机辅助设计方法较好地解决了以上问题.     

基于Autolisp的丝锥槽形设计

目前,国内各丝锥生产厂家所采用的槽形不尽相同,但就其丝锥容屑槽的端面形状而言,应用较多的是＂二圆弧一直线＂型。用作图法作出,笔者认为该方法有如下缺点： （1）设计作图时采用的46°槽形角,限制了作图范围,用此很难满足刃背角η（70°〈η〈90°）的要求。 （2）这种方法没有考虑丝锥槽数,采用一个槽形角,不完全合理。     

丝锥槽形的改进设计

青海工具厂在丝锥生产过程中,发现旧的丝锥槽形存在问题。本文介绍了该厂丝锥槽形改进的经验及其计算公式。并对部分新槽形丝锥与旧槽形丝锥作了切削性能对比试验。试验表明,新槽形丝锥控屑性能好,无切屑堵塞和崩刃现象,并且耐用度有所提高,螺纹表面无刮伤。     

导柱螺旋槽丝锥的设计及工艺方法

导柱螺旋槽丝锥与普通丝锥不同之处在于其带有导柱及螺旋式容屑槽,使其在使用中具有独特的优势,排屑顺畅,加工出的螺纹孔位置度和垂直度较高。本文着重论述了导柱螺旋槽丝锥的设计方法及加工工艺过程。     

立铣刀加工丝锥排屑槽

在机械修造中,有些大直径丝锥常需自制。在制造中,丝锥的排屑槽一般都是用丝锥特形槽铣刀铣出的。我厂在没有特形圆弧槽铣刀的情况下。采用了立铣刀、搬转立铣头角度的方法加工丝锥排屑槽。实践证明,这种工艺方法简便,易于掌握,加工光洁度可达▽6,效果较好。一、立铣刀直径的选择:铣刀直径D=R×3~(1/2)=R×1.732(R-丝锥圆弧槽半径)。如:丝锥孤形排屑槽R=7,则7×1.732=12.1≈12,应选取Φ12立铣刀。     

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.