大直径薄壁半环拉伸模具的设计

分析半环件的成形规律,制定加工工艺方案,对毛坯展开料、模具的几个主要参数、拉伸零件所需冲床规格进行了计算。     

CB125T手把管的弯管机弯曲模具设计

介绍了CB125T摩托车手把管的弯管机弯曲工艺及模具,并以该件为例介绍了CNC弯管机弯模设计中的几何尺寸计算方法。     

介绍几种不对称V形件的弯曲模

从模具的结构、工作原理、设计要点等方面,介绍了几种用于弯曲精度要求较高的不对称V形件的弯曲模。     

压盖落料冲孔成形模设计

介绍了在尺寸公差及形位公差要求较高的落料冲孔成形件的模具设计过程中，不降低劳动效率的情况下，如何使模具简化、降低模具成本，并使冲压件满足其设计要求。     

Z形弯曲件及其模具的特点分析

此文对Z形弯曲件做了较系统的分析归类,并介绍了几种常用的Z形弯曲模的特点,以及这些模具的适应范围。     

手扶拖拉机手把座弯曲成形后开档变小

1零件特点如图1所示的U形弯曲件EM31型手拖中的手把座,采用的材料为A3钢,料厚为3mm.为了保证手把座与变速箱顺利装配,要求弯曲成形保证左端的开档尺寸122_0~(+1.0).手把座右端的开档尺寸要求不高,即使略微超差也不影响装配和使用.     

拉弯成形中导轨型材的回弹计算

分析了用拉伸弯曲法成形面包汽车中导轨零件时的尺寸和角度回弹 ,推导出了此类制品成形模具半径和角度的计算方法     

落料、压形、拉深复合模

图1所示零件,生产批量大,原板料表面已涂有一层装饰涂料,成形后的零件表面又要求无划伤,不起皱,并在一道工序一副模具上冲压成形。经对零件形状及各尺寸进行分析,成形该零件的模具要求具有落料、压形、拉深三种动作功能,为此,我们设计了图2所示的落料、压形、拉深复合模。     

微机上冲裁CAD系统的开发

此文介绍了一套在微机上开发的冲裁CAD系统。它以Foxbase作为数据库管理系统,Trubo C为编程语言,能进行冲裁件图形输入与显示、工艺性分析、优化单排排样和选择板材规格、冲裁件尺寸识别和模具刃口尺寸计算、冲裁力和压力中心计算、以及凹模周界尺寸计算等。本系统主界面为下拉式菜单界面,全中文提示,人机界面友好,具有较好的可扩充性和容错性。     

插片六工位级进模设计

1.引言插片是我厂数种继电器应用量最大的零件之一,图1零件材料为黄铜H62,厚1.2mm,原采用冲压工序为①落料,⑦打扁。由于是单件两工序加工,零件尺寸一致性不好,致使在压扁工序时,零件定位困难,生产效率低,满足不了生产需求,因此我们设计一套六工位级进模二工序在一套模具上完成。2.排样设计通过分析,该零件的台肩,槽口和台肩距边尺寸的略微变化井不影响零件的使用,根据其结构特点,把图1修改为图2,并把原排样形式图3设计成图4所示,其工序为:一工位冲圆孔及切除一边废料;二工位切另一边废料;三工位冲圆孔;四、五工位压扁;六工位落料。3.模具结构及零件加工特点图5为模具结构图。模具采用四导柱、滚珠导套模     

一体化A_mO_n工艺BP神经网络数学模型研究

讨论基于BP神经网络一体化AmOn污水处理工艺数学模型的构建。在分析神经网络和一体化AmOn污水处理工艺各自特点的基础上,建立了具有11个输入层节点、5个输出层节点以及包含两层隐含层的BP神经网络,并确定了各隐含层的节点数、网络的权值和阈值。对模型的验证结果表明:BP神经网络模型基本反映了AmOn一体化工艺的主要特点,网络预测出水结果与实测结果相差不大,神经网络模型具有较好的泛化能力。     

Application of vibration in the laser powder deposition process

Laser powder deposition (LPD) has been used for a few decades as a technique that is unique in the application of complex geometry part manufacturing, high-value parts repairing, and surface modification. However, improving the buildup quality of LPD process is still a challenge because of the presence of defects. In this paper, the effect of in-process vibration frequency on the buildup properties of LPD is studied. Experimental results show that the vibratory energy has a significant effect on reducing porosity. Up to an 80% reduction in the porosity and the maximum defect size can be obtained by choosing the appropriate vibration parameters. In addition, a more homogeneous microstructure is achieved that results in less deviation in hardness throughout the buildup.     

露天煤矿排土场工程地质勘察技术方法浅析

通过对露天煤矿排土场工程地质钻孔勘探的实际工作经验,简要阐明了露天煤矿排土场排弃物层在钻探过程中经常遇到的几个问题,详细论述了解决问题所应采取的技术方法与措施。     

On the Accuracy of Precision Involute Hobs: An Analytical Approach

This paper investigates the impact of the major design parameters of an involute hob on deviations of the hob tooth profile. Desired and actual hob tooth profiles are considered. The desired hob tooth profile is given as the line of intersection of the generating surface of the involute hob by the rake face. The actual hob tooth profile is a certain linear approximation of the desired profile. To evaluate deviation of the actual hob tooth profile with respect to the desired profile, the maximal deviation of the profiles from each other is used. This deviation is measured along the pitch line of the involute hob. An analytical method for computation of the deviation is developed. Using the commercial software MathCAD/Scientific, numerous computer codes are developed. Analysis results reveal a significant impact of the major design parameters of involute hobs on hob accuracy. Optimal configuration of the hob rake face is determined in order to minimize the deviations of the actual hob tooth profile from the desired profile. Based on the research results, reliable ways are proposed for increasing the accuracy of involute hobs in actual practice.     

HTPB药柱老化对SRM内弹道性能的影响及偏差分析

为了定性和定量的描述药柱燃面、密度、燃速等因素对固体火箭发动机（SRM）内弹道性能的影响,在HTPB复合固体推进剂老化研究和SRM内弹道性能预估研究的基础上,分析了HTPB推进剂因贮存老化引起的SRM内弹道性能偏差,建立了性能偏差计算模型。结果表明,老化引起的药柱燃面、密度、燃速变化以及侵蚀燃烧引起的喷喉烧蚀是SRM贮存过程中影响内弹道性能偏差的直接因素,老化引起它们微小的波动都会引起发动机内弹道性能较大的偏离。在发动机寿命预估和进行可靠性分析时必须考虑老化对内弹道性能的影响。     

Bending force prediction for dynamic roll-bending during 3-roller conical bending process

Cylindrical as well as conical cross-section structural parts are widely used in industrial applications worldwide. Such parts are produced from metal plates using many manufacturing methods. 3-roller conical bending process is one such process. In this process first the metal plates in specified blank shapes are given static bending in the rollers. Then the rollers are driven using motors for bending of the blanks under dynamic condition. During bending reaction forces will be there on the rollers. Forces acting on the rollers during the process are transmitted to the machine frame at the roller supports. In the paper an analytical model is developed for the prediction of force during the stage of dynamic bending. The model consists of various parameters like material parameters and geometrical parameters. Experimentation is carried out and the developed model is validated with the experimental results. Effects of various material and geometrical parameters are studied in the present paper. The present work can give insight in the process and can be helpful to the designers as well as to the researchers working in the area of metal forming.     

复杂地形大气污染扩散模式选用研究

在大气环境影响评价中,大气扩散和大气湍流受地形因素的影响较大。在以往的大气环境影响评价中,往往只利用现有的理论模型把实际的情况理想化,公式化导致预测的结果和实际情况有较大偏差。地形越简单,偏差越小;地形越复杂,偏差越大。针对以上情况,从相关的模型入手,主要探讨复杂地形条件下,污染物在大气中的扩散,从而研究复杂地形因素在大气环境影响评价等级判定中的应用。通过分析扩散模型的原理及参数、大气稳定度、扩散参数、复杂地形的处理和建筑物下洗等,得出2008版大气技术导则在原理和技术上,比1993版的大气技术导则的先进性、优越性及在今后环境影响评价工作中应注意的细节。本研究的成果对大气环境影响评价工作将起到极大的促进作用。     

工程塑料环境因素与载荷应力耦合作用试验装置研究

目的 设计一种能够模拟工程塑料实际服役工作环境的试验装置,在多型自然环境中,构建兼具环境因素侵蚀与载荷应力耦合作用的试验条件。方法 研制工程塑料环境因素与载荷应力协同作用试验装置,采用包括拉伸加载、弯曲加载、控制系统等组件的模块化设计,实现0.01~16 Hz加载频率的拉伸及弯曲载荷,最大1 550 kg的拉伸载荷,最大375 kg的弯曲载荷。结果 将研制完成的试验装置置于多型自然环境下对试验施加恒定和交变载荷,以真实模拟工程塑料实际服役中的环境因素与载荷应力协同作用。结论 试验装置制造加工难度小,结构稳定可靠,可用于评价和研究工程塑料等系列类型材料的环境损伤性能演变。     

Springback control of sheet metal air bending process

Press brake bending is a commonly used process for sheet metal part fabrication. It has been observed that the final bend angle, which is the angle achieved upon removal of the punch, is smaller than the initial bend angle. This springback is due to the elastic recovery of the sheet metal. Various theoretical models have been proposed to predict the springback using the tooling geometry and the known properties of the sheet metal. However, in a production environment, the actual properties of any given workpiece may vary from the nominal properties of the lot. This variation causes the actual springback to deviate from the theoretical predictions. This paper presents a practical incremental bending methodology to control punch displacement to achieve more accurate final bend angles. In the proposed approach, workpiece properties are estimated from measured loaded and unloaded bend angles. The estimated properties are used to determine the final punch position required to obtain the desired bend angle after springback. A series of bending experiments was performed. It was found that the proposed method can better predict springback and effectively control the bend angle variation in a production environment.     

核电厂管道局部壁厚减薄快速评定方法研究

目的 解决核电厂实际运行中管道壁厚局部减薄缺陷快速评定的需求.方法 基于RCC-M规范的设计基本要求和核电厂管道评估的实践经验,基于3个工程化的分析假设,提出一种管道壁厚减薄的快速评定方法.其包含三部分内容:1)最小壁厚计算;2)结构完整性评价;3)功能性评价.分别采用管道壁厚减薄快速评定方法和SYSPIPE软件有限元...