长芯棒钢管拉拔的显式动力分析

应用三维非线性有限元分析技术,利用LS-DYNA软件动态模拟了长芯棒拔制的整个过程,得到了钢管任意时刻应力应变分布情况,据此分析了长芯棒拔制相对其他拔制方式而言不会产生缺陷的拔制机理,并探讨了模锥角对拔制力的影响关系,其结果可为优化模具设计提供一定的理论依据和参考.     

轴承内圈抛光用心轴的改进

在对轴承内圈滚道进行抛光时要用到抛光心轴,原抛光心轴为一体结构,使用时主要用前部锥面,如磨损后则整体报废,浪费很大。针对以上情况,将抛光心轴改成两体结构,只要更换前部易损件就可以继续使用,既节约了资金,又节省了加工时间,为生产任务的完成提供了保证,也为以后加工、设计此类零件提供了参考。     

Forming characteristics analysis of the cross-section of axially inner grooved copper tube

The simulation of the cross-section forming of axially inner grooved copper tube (AIGCT) is conducted using finite element (FE) software MSC.Marc. The stress–strain distribution, metal flow rule, and contact force are analyzed based on the simulation and experimental results. The results show that gaps in the groove walls are caused not only by the diametric clearance between the inner wall of the copper tube and the mandrel but also the bending deformation of the copper tube. The cross-sectional geometry and surface characteristics of grooves are determined by the multi-tooth mandrel. Smooth transition of the mandrel teeth addendum improves the metal flow and makes contact force vary slightly, which is good for preventing mandrel from failure. Improving the mandrel surface finish can also improve the inner surface quality of AIGCT. The results help to optimize the forming process parameters and improve the forming quality.     

Slave rotation analysis of miniature inner grooved copper tube through rotary swaging process

Miniature inner grooved copper tube (MIGCT) is widely applied in industries. To overcome the weak rigidity and strength of MIGCT during stepped tubes manufacturing, rotary swaging process was selected after comparing with radial forging process. The working principle of the rotary swaging was analyzed. A rotary swaging machine, whose workpiece feeding and clamping was respectively driven by an air cylinder and a finger cylinder, was designed. Experiments indicate that the MIGCT was slave rotating with forging dies during rotary swaging. Theoretical analysis was done to investigate the reason of the slave rotation. Experiments were carried out to verify the theoretical analysis. Furthermore, the influences of push force and clamping force on rotation speed were discussed. With the increase of clamping force, the rotation speed of MIGCT decreases gradually in a constant ratio. However, the push force influences the tube rotation speed slightly. In general, it found that an optimal rotation speed of MIGCT is beneficial to the manufacture of the stepped tube.     

采用DEFORM-3D铜扁线拉拔成形的研究

根据刚塑性有限元理论,基于有限元分析软件DEFORM-3D,模拟铜扁线的拉拔成形过程,建立铜扁线拉拔的刚塑性有限元模型,获得相关变形网格、温度场和等效应力等完整信息,得出摩擦因数和模角对拉拔力的影响曲线。     

Enhanced boundary lubrication by potential control during copper wire drawing

Metal deformation process, such as wire drawing, is conventionally performed under open-circuit conditions. Lubrication is heavily dependent on the surface conditions of the wire. The surface condition of the wire depends on the electrochemical reactions once the wire contacts with the emulsion lubricant. An oxide layer on the incoming wire could be removed partially or completely and repassivation occurs on the asperities of the wire after abrasion. Adsorption of fatty acid on the oxide layer of the wire could play a vital part in the efficiency of boundary lubrication. Friction could be reduced when a proper potential is applied between the wire and the auxiliary tube before the drawing dies. The reduction of friction detected at various potentials depended on the lubricant chemical composition. Surface quality could be significantly improbed and energy consumption substantially reduced by the potential control.     

基于AutoCAD2002螺旋线的自动绘制程序

利用VBA开发了应用于AutoCAD2002环境下的对数螺旋线自动绘制的程序，解决了工程中常用曲线的迅速、准确绘制问题。     

Experimental study of hydrodynamic propulsion of a medical device with a spiral ribbed impeller

In order to minimize injury during a medical treatment using a low invasive sliding device, loss of cells and tissues due to wear against the device must be prevented by maintaining good lubrication condition. For this purpose, a new medical device with a spiral ribbed impeller has been presented. This paper shows the potentials and problems of the proposed mechanism through experiments. The experimental result confirms that a device can be driven by thrust force keeping noncontacting condition. In some cases, however, the measured thrust force was lower than the theoretical prediction. Cavitation was observed through the transparent impeller in a visualized experiment. It is suggested that a rupture of fluid film associated with cavitation may limits the thrust force and injure tissues. Viscous liquid should be supplied to suppress cavitation if the quantity of the existing mucus is not sufficient.     

小盖拉深胀形镦压模具设计

小盖拉深胀形镦压模具是用来生产GHT6472盘式制动器轮廓组件上轴承的防尘盖零件．该零件虽然结构不复杂，但尺寸精度要求较高．给成形带来困难，为解决此问题，通过对零件的工艺分析、计算，零件拉深成形的特点分析，成形工艺的确定，胀形镦压的条件验算．进行了合理的模具结构设计。     

铜材拉伸生产线在线退火装置

退火工序是铜材拉伸生产过程中重要的辅助工序,合理选用退火装置和退火工艺对拉伸线材质量起关键作用.文中介绍了铜材拉伸生产线在线加热退火的工艺、装置及退火原理,给出了退火工艺参数的确定方法.在线加热退火工艺具有高效率、高质量、低消耗的特点.     

UV-LIGA技术制作微型螺旋形加速度开关

微型加速度开关是用于空间飞行体中感受加速度并完成致动的重要惯性器件。本文采用UV-LIGA技术,结合SU-8厚胶工艺、微电铸工艺以及牺牲层技术,制作了微型螺旋形加速度开关。研究了牺牲层工艺、SU-8光刻技术以及螺旋形弹簧形变控制等微细加工的工艺细节;分析了多种牺牲层材料的特性,优选了与工艺相适应的Zn牺牲层体系,解决了微结构易脱落的工艺问题。通过优化微电铸工艺来减小金属膜层的内应力,优化牺牲层释放工艺来避免腐蚀过程对弹簧膜结构的冲击。实验结果表明,通过工艺优化可得到平整的微型螺旋形弹簧—质量块结构,螺旋弹簧厚度为20μm,质量块厚度达200μm,本文的工作可为大批量、低成本地研制微型加速度开关提供工艺基础。     

Fabrication of porous copper surfaces by laser micromilling and their wetting properties

Porous copper surfaces show their great merits in the applications of chemical reaction, sound absorption and heat transfer. In this study, a laser micromilling method is proposed to fabricate porous surfaces with homogeneous micro-holes and cavities of the size about 1–15 μm on pure copper plates in a one-step process. The laser micromilling was performed by a pulsed fiber laser via the multiple–pass reciprocating scanning strategy. Based on the measurement of scanning electron microscope (SEM) and 3D laser scanning confocal microscope, the formation of surface structures was investigated together with the laser ablation mechanisms. The effects of laser processing parameters, i.e., laser fluence, scanning speed, number of scanning cycles and scanning interval, on the formation and surface morphology of porous surfaces were systematically assessed. Furthermore, the wettability of the porous copper surfaces was also evaluated by measuring the static contact angle of water. The results showed that the laser fluence played the most significant role on the formation of porous copper surfaces. The average depth and surface roughness of porous copper surfaces increased with increasing the laser fluence and number of scanning cycles while decreased with the increase in scanning interval. The scanning speed played little influence on the formation of porous copper surfaces. These results can be closely related to the variation of energy density and re-melting process during the laser micromilling process. Moreover, all the copper porous surfaces were found to be hydrophobic. The contact angle of porous copper surfaces was significantly dependent on laser fluence, but weakly affected by the scanning speed and number of scanning cycles.     

小孔径螺旋齿拉刀设计

设计了小孔径螺旋齿拉刀的构造,给出了螺旋齿拉刀的技术参数,制定了螺旋齿拉刀的技术要求.     

小直径深盲孔中套料芯棒切断刀的研制和应用

本文通过研究套料芯棒的切断机理和大直径芯棒切断刀切削芯棒时的运动轨迹分析,开发出了小直径深盲孔中芯棒切断刀切削套料芯棒时的运动轨迹计算公式,并以此为依据,设计、制造和使用了小直径芯棒切断刀。     

冷凝铜管腐蚀现象显微分析

基于现代分析测试结果,分析制冷机冷凝器铜管电化学腐蚀机理。铜管的结构缺陷和加工缺陷引起冷却水中Fe3+离子沉积,从而发生氧化-还原反应及随后的电化学腐蚀,造成铜管壁穿孔;R22和冷冻机油进入冷却水系统中,提高循环冷却水酸性,加速冷却水管路腐蚀,给冷却水带来更多Fe3+,进而加速铜管腐蚀,造成制冷机失效。     

Isothermal drawing of small boxes from anisotropic oval blanks

The forces involved in the isothermal drawing of thin boxes with large radii from anisotropic blanks are considered as a function of the die speed, the frictional conditions at tool–workpiece contact, and the working pressure.     

有限元模拟软件在铜扁线拉拔力计算过程中的应用

为准确把握铜扁线拉拔过程的拉拔力,首先采用三维造型软件Pro/E 4.0分别建立了铜扁线坯料模型和拉拔模具的有限元模型,然后通过DEFORM软件采用刚粘塑性有限元法对铜扁线拉拔成形过程进行有限元仿真,计算出所需拉拔力.同时采用已有的拉拔力计算公式计算相同规格铜扁线拉拔成型所需的拉拔力.最后将有限元模拟所得结果与通过三个具有代表性公式计算出的结果进行对比分析得知,经过修正后的克拉西里希柯夫公式计算出的拉拔力与模拟出的计算结果最为接近.