结合侧向抽芯和柔性抽芯的注射模设计

根据四通管塑件的结构特点,设计了带侧向抽芯和柔性抽芯的模具结构。侧向抽芯采用液压机构完成直线抽芯,柔性抽芯机构完成曲线抽芯。液压机构抽芯通过控制液压缸的活塞开合动作顺序,避免了侧向抽芯脱模时型芯镶件之间的动作干涉问题。设计的模具抽芯机构在实际应用中运动平稳,抽芯、复位准确,成型的塑件满足使用要求。     

衬套类零件压铸模抽芯结构分析及其液压抽芯设计

通过对衬套类零件压铸模斜滑块抽芯、斜导柱抽芯、齿轮齿条抽芯、液压抽芯结构对比分析，提出液压抽芯可实现此类模具设计的通用化和系列化，并对液压抽芯设计做了进一步阐述。     

自锁抽芯机构特征及设计要点

抽芯机构是塑料模具设计中的一个重要组成部分,抽芯机构形式繁多,本文中的自锁抽芯机构是一种新型抽芯形式,它既有液压抽芯的平稳,也有斜滑块抽芯的可靠。     

臂座压铸模抽芯结构的改进

抽芯机构是压铸模常见的机构之一,当铸件具有与开模方向不同的内外侧凹时,模具需要侧面分型,先将抽芯抽出,然后顺利顶出铸件。雨刮器臂座侧面孔为倒扣结构,需要做成抽芯结构。前期模具设计采用大方形抽芯镶拼结构,在实际生产过程中,方形抽芯断裂频繁,备件制造工序长,加工周期长。后期,对抽芯结构进行改进,改为小异形抽芯镶拼结构,减少抽芯应力集中,提高抽芯使用寿命,降低抽芯制造成本和缩短制造周期,现该结构已普遍用于臂座压铸模。     

细长塑件注射模特殊抽芯机构的设计

根据细长塑件端部的特殊结构来设计模具抽芯机构,设计的抽芯机构为1个主体轴向抽芯带动6个径向小抽芯机构.     

齿轮齿条在注射模侧向抽芯机构中的应用

常用的侧向抽芯机构是斜导柱、斜滑块，当塑件上的抽芯距较长、抽芯力较大或斜向侧抽芯时，斜导柱、斜滑块抽芯比较困难，而采用齿轮、齿条就非常方便。掌握长抽距或斜抽芯塑件的结构工艺分析及抽芯距、抽芯力的计算，齿轮、齿条注射模侧向抽芯机构的原理和齿轮、齿条设计要点尤其关键。     

弯销二级侧抽芯机构

对于薄壁制品侧面需要侧抽芯，为了防止侧抽芯时将塑件壁部被夹变形或损坏，因此采用二级侧抽芯。本机构利用弯销的延时侧抽芯特性，用弹簧弹顶进行第一次侧抽芯，弯销进行第二次侧抽芯。     

滑块抽芯机构及其应用

滑块抽芯机构及其应用湖南建材高等专科学校（湖南衡阳４２１００８）刘吉兆１引言抽芯机构的作用是在模具开启时,将注塑机的开模力通过抽芯机构来改变方向,从而将滑块从制品中抽出。依据该原理可设计出多种抽芯机构,现介绍一种滑块抽芯机构。２滑块抽芯机构滑块抽芯机...     

注射成型管件内螺纹质量分析及模具抽芯机构设计

介绍了内螺纹管件在脱模时容易变形的问题,提出了解决这类管件脱模问题的抽芯机构设计方案,论述了抽芯机构的结构特点和工作原理,通过滚珠丝杆带动滑块抽芯与螺纹型芯旋转抽芯时的螺距一致,使塑件抽芯动作运行平稳,有效解决了内螺纹塑件在抽芯时产生的起牙损坏、拉伤等问题。     

铝合金接线盒压铸模设计

分析了接线盒铸件结构特点,设计了双侧抽芯式模具;介绍了短距离抽芯一侧采用斜导柱抽芯,长距离一侧采用液压抽芯。     

阿那其根醇提取物对两种炎症模型作用机制研究

目的: 研究阿那其根醇提取物(EERAP)对二甲苯致小鼠炎症模型和脂多糖(LPS)诱导RAW264.7细胞炎症模型的影响。方法: 将50只小鼠,随机分为对照组(饮用水)、EERAP高剂量组(640 mg/kg)、中剂量组(320 mg/kg)、低剂量组(160 mg/kg)和阿司匹林组(120 mg/kg),采用二甲苯建立小鼠炎症模型,比较小鼠耳廓肿胀度及耳廓毛细血管通透性的变化,ELISA法测定各组炎症渗出液丙二醛(MDA)、超氧化歧化酶（SOD）的含量;LPS诱导RAW264.7细胞建立细胞炎症模型,ELISA法测定核转录因子kappa B（NF-κB）和肿瘤坏死因子-α（TNF-α）含量。 结果: 在二甲苯致小鼠炎症模型中,EERAP高、中、低剂量组均能抑制小鼠耳廓肿胀度,减少小鼠耳廓毛细血管通透性,减少渗出率,与空白对照组比较均有统计学差异(P<0.01);EERAP高、中、低剂量组均能降低血清中MDA含量（P<0.05）,显著升高SOD含量(P<0.01);在LPS诱导的RAW264.7细胞炎症模型中,EERAP在3.125～200 μg/mL范围内可降低TNF-α含量,而在2 μg/mL时也可以降低细胞NF-κB含(P<0.05),与阿司匹林组无统计学差异。结论: EERAP可能是通过抑制MDA、TNF-α和NF-κB的生成,升高SOD的水平,起到抗炎、抗氧化作用。     

Mechanism of improvement of formability in pulsating hydroforming of tubes

The mechanism of improvement of formability by the oscillation of internal pressure in a pulsating hydroforming process of tubes was examined. Free bulging hydroforming experiments of mild steel tubes under oscillating and constant inner pressures were performed. For a high constant pressure, a round bulge with local thinning was observed, whereas wrinkling occurred for a low constant pressure. The occurrence of these defects was prevented by oscillating the internal pressure in the pulsating hydroforming. In the pulsating hydroforming, a uniform expansion in the bulging region was obtained, and thus the formability was improved by preventing the local thinning. It was found from an observation of deformation behaviour, using a video camera, that the tube is uniformly expanded by repeating the appearance and disappearance of small wrinkling. The cause of the uniform expansion for the pulsating hydroforming was also interpreted from the variation of stress components. In addition, a similar deference in deformation behaviour between the oscillating and constant inner pressures was also obtained in finite element simulation.     

钛铁矿烧结性能研究

将钛铁矿在氩气及空气气氛中不同温度下进行烧结。采用XRD及热分析研究了钛铁矿在不同温度下烧结后的相组成及质量变化。结果表明,在氩气气氛950℃下烧结后,钛铁矿的物相组成没有发生变化;在空气中不同温度烧结后,600～800℃较低温度区间,钛铁矿转变为热力学亚稳定的Fe2Ti3O9,950℃以上烧结时,钛铁矿转化为热力学稳定的Fe2TiO5。钛铁矿的晶体结构由烧结前的三方结构经低温烧结后转变为亚稳态六方晶系的Fe2Ti3O9,950℃以上烧结后,晶体结构转变为斜方晶系的Fe2TiO5。     

Calculation of the parameters of pulsed laser welding of thin sheets of aluminium alloys

One of the main advantages of the MIG/MAG process is its high productivity. In most of the applications, positive polarity is used, due to its greater arc stability, generation of less splatter and formation of weld beads with suitable geometry. However, in some applications, there is a need for greater production capacity than that offered by conventional MIG/MAG welding. In the literature, it is stated that negative polarity provides a higher fusion rate than positive, despite leading to a high level of splatter and unsuitable formation of the weld bead. Unfortunately, there is not much information available on the effects of the process variables in this polarity, much less justification for such. Therefore, this work is an attempt to try to understand the reason why there is a higher deposit rate in negative polarity, as well as the related effect on the geometry of the weld beads. To do this, comparative MIG/MAG welds were produced in both positive and negative polarities, using two compositions of shielding gases at two current values. The transfer mode and the behaviour of the arc were analysed by synchronized profiling. The geometric profile of the weld bead was evaluated by means of metallographic procedures. From the results, which disagree in part with the current literature, it was seen that both the transfer mode as well as the morphology and the appearance of the weld bead are dependent on the composition of the shielding gas. To explain the phenomena inherent in the greater fusion rate of wire in DC ? , the suggestion is that the fact that arc scales the sides of the wire in this polarity may be the governing factor.     

Inhibition of copper corrosion by coatings of alkyl esters of carboxybenzotriazole

The inhibitive effect of coatings formed dipping copper in solutions of alkyl esters (methyl, butyl, hexyl and octyl) of carboxybenzotriazole was studied by potentiodynamic polarisation, electrical impedance spectroscopy, coulometry and surface enhanced Raman scattering (SERS) spectroscopy. The inhibition efficiency of the dry film depends on type of solvent used in the coating solution, temperature and period of immersion. Pretreatment by immersing copper in hot (70 °C) aqueous solution (1×10⁻⁴ M) for approximately 2-3 h gave a film with the highest degree of corrosion protection. Higher temperatures or longer time of immersion reduce the protectiveness of the film. Copper coated using either alcohol or acetone as solvent was less well protected than when dipped in aqueous solution. Impedance spectra showed that the film formed by pretreatment in aqueous solution of inhibitors can be stable in acidic sulphate corrodent (pH∼0) for up to 3 days before breaking down. In near-neutral sulphate solution (pH∼8) the film can be stable for up to 10 days. In both acidic and neutral sulphate solution, the inhibition efficiencies of the protective film increased with the length of the alkyl ester chain in the order: methyl < butyl < hexyl < octyl. This is different to the behaviour of copper in a near-neutral aqueous corrodent containing dissolved inhibitor. The ester films also exhibit anti-tarnishing properties in a sulphidising environment with inhibition efficiencies increasing as the alkyl chain is made longer. Again the films formed by pretreatment in aqueous solution have superior anti-corrosion properties compared to those formed by pretreatment in either alcohol or acetone solution. SERS measurements indicate that the azole ring is close to the copper surface with chemisorption through azole nitrogen. It is also suggested that the hydrocarbon chain of the ester is physically adsorbed on the copper.     

滑阀污染敏感尺寸的确定

本文根据滑阀运动副发生污染卡紧与污染磨损的污染物尺寸条件,给出了滑阀污染敏感尺寸范围。试验结果很好地证明理论分析的正确性。这对于确定液压系统中滑阀所需要的过滤精度具有重要价值。     

Development of the technology of ultrasonic welding of components made of Capron tapes

The technology of ultrasonic welding of components made of Capron tapes producing welded joints with high strength parameters has been developed. The numerical values of the main parameters of the conditions of ultrasonic welding of the Capron tapes are determined. It is shown that the increase in the amplitude and welding pressure shortens the welding time. The experimental results show that the Capron tapes are characterized by geometrical homogeneity in both the transverse and longitudinal direction so that the welded joints can be produced both along and across the tape.     

板料拉延中的润滑

论述了板料拉延成形时的摩擦、磨损特征和润滑机理 ,探讨了拉延时润滑油的使用问题 ,为生产实际中润滑油的选择提供了理论根据和实用参考。     

焊丝含碳量对高强度钢焊缝性能的影响

报导了焊丝中含碳量在0.09～0.18％范围内时对45CrNiMoV高强度钢焊缝力学性能的影响。随焊丝中含碳量的增加,接头强度上升,焊缝韧性下降。     

柔性加工系统FMS的Web数据库开发

论述了建立制造企业网与Web数据库的必要性。分析了互联网络环境中柔性加工单元的制造模式。详细讨论了用JDBC编写Web数据库应用程序的原理。最后分析了Web数据库存在的安全防护问题