改善压铸件表面粘模缺陷的方法和措施

压铸件粘模缺陷直接影响着产品的外观和强度,尤其是有密封要求的铸件,粘模严重会导致局部泄漏,造成不必要的浪费。针对压铸件出现粘模的原因,从化学原理、模具结构、脱模剂成分、压铸工艺参数四个方面进行分析,并采取相应的措施,大幅降低了不良率。     

“900型”压铸机中停装置

上海微型电机厂在“900型”压铸机上生产的压铸件中,有较大数量是装有嵌件的,为了便于放置嵌件及在试模时看清模具慢动作动态,设置了开模过程中的中间停车装置,其原理如下图所示。     

铝合金压铸件缺陷及模具分析

针对压铸件出现的拉伤、气孔、冷隔及粘模等各种缺陷,从力学、热力学、流体动力学角度,分析讨论了压铸模设计及压铸件产生质量问题的原因,为改进模具指出了明确方向。     

纯电动汽车电机壳体压铸模具设计与实践

利用3D打印水道和高压冷却相结合的模具冷却系统,实现纯电动汽车电机壳体模具均匀冷却,将传感器和电磁阀与压铸设备控制系统连接,实现模具工作温度智能控制,解决模具粘铝问题,提高铸件内部品质和生产效率.研究结果对类似复杂结构的汽车零部件开发具有参考意义与应用价值.     

空气阻力显示器壳体注射模结构改进

空气阻力显示器壳体原注射模采用机外脱模的方式，操作者劳动强度大，效益较差。通过对模具结构的重新设计，采用两滑块抽芯，推管推出，壳体模内脱模，嵌件和插件随塑件一起出模，降低操作者劳动强度。该模具经过生产验证，结构合理，能满足生产的需要，班产量也翻一番。     

解决压铸件粘模缺陷的具体措施

在压铸生产或新模具试模时,经常会出现铸件粘模的现象。文中详细分析了铸件粘模的原因,探讨了防止粘模的具体措施,以便更好地消除铸件粘模现象和提高压铸件质量。     

轴销形嵌件在压铸模具里的装配方法

轴销形嵌件在压铸时,嵌件出现的表面飞边、划伤和尺寸超差的缺陷,在采用压紧嵌件的紧固销和弹簧后,消除了嵌件表面出现的飞边。在把模具安装嵌件的孔做出起模斜度,使嵌件的有效使用部分与模具孔不直接接触时,消除了嵌件表面拉伤的痕迹。为防止嵌件自动掉落下来,在压铸模具里设置磁铁后,可将铁质嵌件牢牢地吸附固定在模具里。     

镁合金变速箱壳体的压铸工艺优化

基于Power-Cutoff模型,利用ProCAST软件在液态至半固态的浇注温度区间内,对AZ91D镁合金变速箱壳体压铸工艺进行了分析。通过正交试验研究了冲头压射速度、浇注温度、模具温度以及模具与压铸件间传热系数对镁合金变速箱壳体压铸件内缺陷率的影响规律,并优化了工艺参数。结果表明,在保证AZ91D镁合金的内浇道充型速度为40~90m/s时,冲头压射速度对压铸件内最大缺陷率的影响不明显,但较低的压射速度能明显降低压铸件内的总缺陷率。半固态浇注温度区间、较高的模具温度以及较低的模具与压铸件间传热系数均能显著降低压铸件内最大缺陷率以及总缺陷率。最终得到的最优工艺参数:冲头压射速度为5m/s,浇注温度为570℃,模具温度不低于200℃,模具与压铸件间传热系数为500W/(m2·K)。     

铝合金电控壳体压铸件裂纹缺陷分析与优化

为满足新能源汽车轻量化的要求,电机控制器壳体通常采用铝合金压铸件,而铸件裂纹是其常见的缺陷形式。针对某电控壳体的裂纹缺陷,从化学成分、显微组织、力学性能、模流、脱模过程等方面进行失效原因分析。结果表明,脱模过程中的顶杆作用力是导致裂纹产生的主要原因。对顶杆位置进行优化,并进行仿真和试验验证,优化后的顶杆位置可以有效避免压铸裂纹的产生。     

变速箱壳体3D打印熔模铸造工艺分析北大核心CSCD

以变速箱壳体铸件试制为例,分析了3D打印蜡模石膏熔模铸造技术路线、关键工艺过程和应用效果,对3D打印蜡模及铸件产品精度进行了测量分析。结果表明,3D打印蜡模石膏熔模铸造技术工艺过程稳定,铸件精度高,适用于快速试制铝合金铸造新产品样件。     

Stencil printing behavior of lead-free Sn-3Ag-0.5Cu solder paste for wafer level bumping for Sub-100 μm size solder bumps

Stencil printing for flip chip packaging using fine particle solder pastes is a low cost assembly solution with high throughput for fine pitch solder joint interconnects. The manufacturing challenges associated with both solder paste printing increases as electronic device size decreases due to trend of miniaturization in electronic components. Among multiple parameters, the two most important stencil printing parameters are squeegee pressure and printing speed. In this paper, the printing behavior of Pb free Sn-3Ag-0.5Cu solder paste with a particle size distribution of 2–12 μm for wafer level bumping using a stencil printing method (stencil opening dimension ?30 μm) was evaluated by varying the printing speed and squeegee pressure to fabricate solder bumps with a sub 100 μm size. The optimal squeegee pressure and print speed for the defect free printing behavior and fairly uniform size distribution of reflowed paste were found to be 7 kgf and 20 mm/s, respectively. The average size of the reflowed printed paste decreased with the increasing squeegee pressure.     

AZ91D摩托车发动机壳体压铸模设计

针对摩托车发动机壳体的结构特点及工艺要求,介绍了一种切实可行的压铸模设计方案。该压铸模选择最大截面为分型面,浇注系统设计时采用FLOW-3D仿真软件进行模拟填充,用模温机及循环的冷却水控制模具温度,设置斜销式抽芯机构。经生产实践证明,铸件达到了图纸的各项要求,并已进行小批量生产。     

Modeling of high temperature- and diffusion-controlled die soldering in aluminum high pressure die casting

Soldering of cast alloys to the dies has been a continuing source of die surface damage in the aluminum die-casting industry. To reduce the repair and maintenance costs, an approach to modeling the damage and predicting the die lifetime is required. The aim of the present study is the estimation of the die lifetime based on a quantitative analysis of die soldering in the framework of the numerical simulations of the die-casting process.Full 3D simulations of the process, including the filling, solidification, and the die cooling, are carried out using the casting simulation software MAGMAsoft. The resulting transient temperature fields on the die surface and in the casting are then post-processed to estimate the die soldering.The present work deals only with the metallurgical/chemical kind of soldering which occurs at high temperatures and involves formation and growth of intermetallic layers. The die-soldering model combines two approaches available in literature, describing the two aspects of die soldering: the growth of the intermetallic layer, and the thermal and metallurgical conditions in the layer that lead to the die soldering. The theoretical model is then extended with the treatment of the intermetallic layer growth controlled by the idealized effective diffusivity and with the treatment of solder strength dependent on the temperature and liquid fraction within the layer. The solder strength locally on the die surface is calculated as a function of the number of die-casting cycles. This also provides the estimation of the die lifetime defined as the number of cycles until the critical solder strength level is reached.Proper validation of the model is required, and the model parameters (the critical solder strength value, among others) need to be calibrated by measurements and data from the die-casting industry.As an example, the model is applied to several cases of high pressure die casting (HPDC) where A380 alloy parts are cast in the H13 steel die. The predicted locations of the higher strength of soldering appear in the “hot spot” areas of the die surface in agreement with the reports in literature. The influence of several casting process parameters such as cooling/spraying efficiency and other parameters that control the thermal history of the die and the casting is in agreement with the expected behavior.     

田口试验法在PBGA焊点可靠性中的应用

在田口试验法的基础上,采用非线性有限元建模的方法对温度循环载荷作用下的PBGA(plastic ball grid array)焊点进行可靠性研究。PCB(printed circuit board)的大小和厚度、基板的大小和厚度、焊点的直径和高度、芯片以及塑封(EMC)的厚度等8个控制因子被选择用来填充L18田口正交表。通过田口试验法优化之后得到最佳的控制因子组合为A1,B3,C1,D2,E2,F3,G3,H3,其中最重要的4个因子为焊点直径A,PCB大小B,芯片厚度F,焊点高度G。结果表明,优化后的试验值和预测值分别比原始状态的试验值和预测值提高了2.87964和0.88286。     

汽车壳体低压铸造工艺与模具设计

介绍了汽车壳体零件低压铸造工艺与模具设计.内容主要有低压铸造工艺参数的设计,包括升液压力与升液速度、充型压力和充型速度的计算、浇注温度的确定、结晶压力和保压时间的计算等;模具设计,包括模具结构与壁厚的确定、型腔尺寸的计算、型芯和抽芯的计算、模具的三维造型.     

基于UG／Mold Wizard高速压铸模具设计

利用UG／Mold Wizard技术以及相关模块,采用全参数化驱动对铝合金产品进行模具设计。针对铝合金模具与注塑模具相似的特点,研究了Mold WiZard在压铸模具中的应用,在三维CAD中实现快速准确分模,同时利用uG软件自身的特点,实现全参数化的自由编辑,达到铝合金高速压铸模具全三维化设计的目的。基于UG／Mold Wizard的模具设计,可大幅缩短模具设计周期,降低成本,增强企业竞争力。     

3D封装芯片焊点可靠性有限元分析

选择工业中广泛使用的Sn,Sn3.9Ag0.6Cu钎料作为三维封装芯片键合焊点材料,采用ANSYS有限元软件建立三维封装模型,基于Garofalo-Arrhenius本构方程,进行?55 ~ 125 °C热循环模拟,并通过田口法探讨封装结构和工艺参数对焊点的可靠性影响. 结果表明,Cu柱与焊点接触处是整个结构的薄弱区域,在IMC焊点阵列中最右列第二个焊点处出现最大应力. 通过田口法,结合有限元模拟结果,获得了4个因子对S/N的贡献度由大到小依次为:焊点阵列、焊点高度、芯片厚度、焊点材料. 其中焊点阵列的影响最大,其次是焊点高度、芯片厚度,焊点材料影响最小. 基于优化设计,获得了最优的匹配组合为3 × 3阵列,焊点高度0.02 mm,芯片厚度0.2 mm,焊点材料Cu₆Sn₅.     

压铸模具的计算机辅助制造

以实例说明了压铸模定型的三维计算机辅助制造工艺及加工方法。详细介绍了定型型腔修正铜公（铜电极）的加工方法及要求。     

The Effect of Temperature Condition on Material Deformation and Die Wear

The characteristics of temperature change on die and billet are very complex during the deformation process because of the interaction between them and some unstable external factors. In this paper, the numerical simulation model for the crank shaft die forging was established by means of the rigid-plastic FEM method. The model was validated by optical non-contact 3D measurement—ATOS. Based on available research results, this paper explored the effect of temperature conditions on material deformation and die wear. Three parameters, press velocity and initial temperature of billet and die, were chosen to illustrate the effects. From the experimental results, the effect of process parameters on deformation ability of the material is simple, while the effect on die wear is relatively complicated. The press velocity plays an important role on die wear when the initial temperature of the billet has larger influence on material deformation. A conclusion can be drawn that when the initial temperature of the billet is 1100 °C, the initial temperature of the die is 250 °C, and the velocity is kept in the range of 200-300 mm/s, the optimum solution for deformation ability of the material and die wear can be obtained. It is possible for the conclusion to be extended further for the control of temperature condition to optimize die life and material deformation.     

压铸模具的计算机辅助制造

以实例说明了压铸模定型的三维计算机辅助制造工艺及加工方法。详细介绍了定型型腔修正铜公 (铜电极 )的加工方法及要求