PCB外壳注射模设计与模拟分析

对成型PCB外壳的注射模设计及模拟分析进行研究,分析PCB外壳的结构和工艺,运用模拟分析软件创建有限元模型,对注射过程中的填充、冷却与翘曲等进行分析,验证了注射模结构的合理性,注射效率高,成型塑件的翘曲变形量小。     

Moldflow/MPI在双色注射成型中的应用

利用三维模拟软件Moldflow/MPI对MP3内、外壳双色注射成型过程进行模拟分析,对熔体充模时间、塑料熔体温度分布、塑件冷却温度和塑件翘曲进行分析比较,优化了双色注射成型工艺及模具设计。     

基于HSCAE的电器外壳注射模优化设计

采用HSCAE软件对电器外壳的注射成型过程进行了模拟,分析了塑件翘曲变形的原因并提出了改进措施,对塑件成型工艺进行了优化,提高了塑件成型质量和生产效率,为类似塑件的注射模设计提供了理论依据。     

防爆灯外壳铸改挤工艺仿真与分析

为了解决防爆灯外壳在铸造过程中高温对模具的热侵蚀问题,同时改善防爆灯铸件内部的缩孔、气孔等质量问题,增强产品防爆性能,把铸造工艺改为等温挤压工艺。通过对防爆灯外壳成形过程的仿真研究,对防爆灯铸件的结构进行了一系列有利于挤压成型的改善,并通过ANSYS结构分析模块优化产品结构,在达到产品质量要求的前提下尽量降低成本。最后通过有限元手段模拟成形过程,并对其成形结果进行分析。     

基于Taguchi正交试验的超薄笔记本外壳注射工艺优化

以某款14英寸超薄笔记本电脑外壳为研究对象,选择不同的模具温度、熔体温度、注射时间、保压时间和保压压力作为工艺条件,在Moldflow仿真平台进行Taguchi正交试验,获得在不同参数组合条件下的外壳翘曲量。结果表明模具温度对翘曲变形影响程度最大,其次是保压压力、熔体温度、保压时间和注射时间,通过优化分析确定了超薄笔记本电脑外壳件注射成型的最佳工艺参数组合,模拟结果显示在该条件下外壳的翘曲量最小。最后,将最优参数组合运用到实际生产,所得到的结果与模拟分析一致。     

单腔斜顶双滑块抽芯成型工艺分析与注塑模具设计

应用华塑CAE软件对温度监测器外壳塑件的工艺性进行了分析，根据浇口位置分析结果和外观要求，确定了浇口的最佳位置。通过对充模、保压、冷却过程的模拟分析，实现了平衡浇注，减少了可能出现的变形、气泡、拼接线等缺陷，优化了注塑成型工艺参数，创新设计了斜顶、双滑块抽芯的单腔二板式模具。应用UG10.0设计了温度监测器外壳三维模型及二维装配图，介绍了模具成型工作原理。实践结果证明，模具结构具有新颖性，本文模流分析方法应用及模具结构可为壳体类的模具设计提供参考。     

供氧面罩外壳凸凹模对模成型模的设计与制造

供氧面罩外壳是一种由玻璃钢织物和树脂胶为材料,在成型模上进行裱糊后固化的零件.在通过对单模的成型工艺分析,发现这种成型方法会使供氧面罩外壳产生形状扁塌的现象,还会有起皱、脱胶、聚胶和气泡等缺陷.由于供氧面罩外壳批量小,采用喷射接触成型工艺方法,又因投资过大的原因而放弃.通过对供氧面罩外壳成型工艺过程的详细分析,确定采用对模成型的工艺方法进行成型加工.实践也充分地证明了采用对模成型工艺方法来制造供氧面罩外壳,不仅能够确保供氧面罩外壳的质量要求,而且具有操作简单,加工便利,投资低的特点.     

基于正交试验和Moldflow的后视镜外壳注射工艺优化及模具设计

通过对汽车后视镜外壳结构、实际使用及外观要求进行分析,以模具温度、熔体温度、注射压力、保压压力、保压时间为影响因素,确定5因素4水平的正交试验方案,基于Moldflow软件模拟分析了工艺参数对翘曲变形的影响。结果表明,最优的工艺参数为模具温度50℃、熔体温度210℃、注射压力150 MPa、保压压力85 MPa、保压时间40 s。结合Moldflow分析结果,并利用UG完成汽车后视镜外壳注射模的设计,解决了成型塑件倒扣脱模机构、侧抽芯机构及内抽芯的斜楔机构的设计难题,为汽车后视镜外壳以及同类型产品的成型提供参考。     

基于Moldflow的电机塑料外壳成型优化分析

利用Moldflow对电机塑料外壳进行成型过程分析。通过对填充、流动以及翘曲的数值模拟,预测塑件可能出现的缺陷,其中翘曲变形是影响塑件质量的重要因素。通过采用修正成型工艺参数和改变网格厚度的方法可以减小塑件的翘曲变形量,并获得最佳工艺参数组合,从而提高塑件的质量。模拟分析方法提高了试模效率,缩短了产品开发周期。     

基于CAE的同模异腔熔体流动平衡优化设计

针对同一副模具中一次成型多个异形件的浇注系统非平衡问题,以数码相机外壳为例,运用Moldflow软件的流道平衡模块对熔体进行流动成型分析,根据经验和公式计算确定初始方案,依据CAE分析结果,调整型腔布局、优化流道截面形状和改进浇口尺寸,设计了2种不同的优化方案,通过分析比较,确定最优设计方案,实现了浇注系统的熔体流动平衡,提高了数码相机外壳的成型质量。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.