共查询到19条相似文献,搜索用时 437 毫秒
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基于模流分析,利用田口(正交)试验方法对汽车门把手的气体辅助注射成型工艺进行优化,使其达到最优的初始气体穿透量,得到合格的制品。选择注气时间、注气压力、注气延迟时间、预注射量4个主要因素进行正交模拟试验。用四因素三水平正交试验表进行模拟试验设计,采用方差分析法研究了这4个因素对初始气体穿透量的影响,得知其中影响较大的因素是预注射量。对气体辅助注射成型工艺进行优化,为改善制品质量、得到合格穿透深度的制品提供指导,从而缩短试模时间,提高生产效率。 相似文献
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气辅注射成型参数设置不合理会造成吹穿、气指、缩水、穿透不足等各种成型缺陷.利用Moldflow软件采用正交实验法对提手GAIM的主要工艺参数:熔体温度、注射时间,熔体体积、气体延迟时间、气体注射时间,及压力进行模拟分析,在对每次实验结果进行分析基础上,对成型参数进行进一步优化.采用优化工艺,气体贯通整个提手,产品质量减... 相似文献
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塑料熔体充填过程中的微结构形态对注塑制品性能影响很大,是注塑制品控形、控性的基础,使用格子玻尔兹曼法(lattice Boltzmann method, LBM)中的HCZ(He-Chen-Zhang)模型能模拟注塑过程中复杂的多相流和微结构形态演化过程。通过开发HCZ模型的程序,模拟了模具型腔内熔体流动的Poiseuille流。研究表明,模拟结果与理论解基本吻合,验证了HCZ模型能准确地模拟塑料熔体的非线性流动行为。使用HCZ多相流模型模拟了注塑熔体充填和气辅成型气体穿透过程,模拟的注塑熔体流动前沿"喷泉效应"与实际成型过程相符,气辅成型气体压力不仅影响气道厚度,而且影响厚度的均匀性。 相似文献
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介绍了气体辅助注射成型的工艺过程、特点,气体辅助模设计的基本方法、要求和几种常用控制熔体均衡填充型腔的方法。阐明注射喷嘴进气比模具型腔进气在改善制件的外表面质量及生产效率有更大的优势。利用CAE模拟技术优化气道尺寸和气道布置。 相似文献
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0 IntroductionTheweldmodelingandcontrolareveryimportanttothemechanicsofweldprocessandhowtheycanbebestutilized.Thesatisfiedcontroloftheoverallweldprocessisnoteasilyaccomplished,largelyduetotheinadequaciesoftheavailableprocessmodels.Thearcweldingprocesst… 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):280-285
AbstractA feasibility study has been conducted to determine whether a hollow cathode arc (HCA) can be used for a welding heat source in space, that is high vacuum and microgravity conditions. The HCA method enables the arc discharge to form under low pressure conditions by purging a small amount of gas through the centre of the hollow cathode. The characteristics of HCAs under low pressure conditions have been experimentally investigated, in particular the melting properties and voltage-current characteristics. Results show that the penetration profile and arc characteristics of the HCA method are sensitive to process parameters such as gas flowrate, arc length, and inner diameter of the electrode, and that the penetration in HCA melting is extremely deep under the conditions of low gas flowrate and long arc length. 相似文献
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利用自制的活性剂,考察了焊接工艺参数对奥氏体不锈钢A-TIG焊焊缝熔深的影响.结果表明:活性剂能使电弧收缩,穿透力增强,使焊缝熔深增加.在其它焊接参数不变的情况下,随着焊接电流的增加熔深增大;随着焊接速度的增加熔深减小;焊接电弧长度由2mm增加到3mm,焊缝熔深增大;由3mm增加到4mm,焊缝熔深减小.电弧收缩理论可以较好地解释试验结果. 相似文献
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Hump formation mechanism in gas-jet-assisted keyhole laser welding of HR-2 stainless steel
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Gas-jet-assisted keyhole laser welding offers the possibility of a breakthrough in the limitations of penetration depth in laser welding,which currently suffers from equipment restrictions.A gas jet of sufficient intensity to assist the keyhole should be used to obtain suppressed plasma,a deepened keyhole,and increased penetration depth.However,an excessively strong gas jet gives rise to humps.The incident angle of the keyhole-assisted gas jet is 60°,with a nozzle ahead of the laser beam.A series of experiments were carried out with different welding velocities and gas parameters by using HR-2 hydrogen-resistant stainless steel and a slab CO_2 continuous-wave laser welding machine.The weld profiles can be categorized into four types,welds of traditional laser welding,welds of enhanced laser welding,undercut welds,and humping welds with increased gas pressure.A high-speed camera was employed in the experiments to monitor the formation of humps under an excessively strong gas jet.The results of analysis show that hump formation can be divided into six stages.Its main driving force is the intense turbulence of gas jet.There are two main reasons for hump formation:premature solidification of the molten pool caused by the large temperature gradient between the front and rear parts of the molten pool,and the emergence of a thin layer liquid bridge with one-directional flow under the enhanced cooling effect of excessively strong gas. 相似文献
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针对非熔化极气体保护焊(gas tungsten arc welding, GTAW)过程中因焊接参数波动、热传导条件变化难以实时检测和控制熔透的难题,考虑304不锈钢相变潜热随温度的变化,建立了焊接电参数与熔池相变潜热、背面熔宽间的动态变化数学模型,仿真研究了改变焊接电流、电弧电压对焊缝熔透状态的动态影响规律,预测了恒定电参数下点焊熔透状态发生改变的时间. 采集了同参数焊接过程中表征熔透状态变化的反射激光点阵视频图像,统计计算了实际熔透发生改变的时间. 结果表明,所建立的动态数学模型能够反映焊缝熔透状态随电参数的动态变化过程,且焊接电流对熔透状态的影响更显著;熔透变化预测时间与实测时间一致. 相似文献
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基于0Crl8Ni9Ti奥氏体不锈钢超高频脉冲钨极氩弧焊(UHF—GTAW,ultrahigh frequency pulse gastungsten arc welding)试验,分析了脉冲电流参数对奥氏体不锈钢电弧行为的影响及其作用规律.结果表明,以脉冲电流频率、占空比为代表的脉冲电流参数对不锈钢UHF-GTAW电弧的电学特性、工作形态、电弧力及熔透特性具有较大影响,随着超高频脉冲方波电流频率的增加,电弧收缩效应增强,电弧覆盖面积在一定范围内减小,电弧力显著增长,以等离子流力及电磁力为主的轴向力作用于熔池表面液态金属,造成熔池表面凹陷、热源下移、焊缝熔深增大、熔透率显著提升. 相似文献
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C.S. Wu J. Q. Gao Y.H. Zhao 《金属学报(英文版)》2006,19(1):27-33
Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width with sufficient accuracy. A neural network model is developed to attain this aim. Welding experiments are conducted to obtain the training data set (including 973 groups of geometrical parameters of the weld pool and back-side weld width) and the verifying data set (108 groups). Two data sets are used for training and verifying the neural network, respectively. The testing results show that the model has sufficient accuracy and can meet the requirements of weld penetration control. 相似文献
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通过工艺试验,研究了双丝共熔池窄间隙焊焊丝与侧壁间距、双丝前后间距和双丝倾角3个工艺参数对焊缝成形的影响.结果表明,焊丝与侧壁间距减小,侧壁熔深和表面下凹增加;沿焊接方向双丝倾角为零时,侧壁熔深和表面下凹达到最大值;而在电弧和熔池热量的共同作用下,双丝前后间距增大,侧壁熔深和表面下凹先增大,后减小,在5~10 mm内达到最大值.在不形成指状熔深时,这3个参数对焊缝熔深影响不大.采用I形坡口会出现底部未熔合,调节这3个参数不能消除未熔合现象. 相似文献