基于CAE的塑件翘曲变形分析与工艺参数优化

在分析翘曲变形理论的基础上,利用正交试验方法设计了L27实验矩阵对塑件注射成型过程进行模拟研究,分析了模具温度、熔体温度、注射速率、保压压力、冷却时间、保压时间等工艺因素对塑件翘曲变形的影响,得出了最优化的工艺参数设置,并分析了各单一因素对翘曲和收缩率的影响趋势及其原因。研究表明:所选择的工艺参数对塑件不同方向上的翘曲变形有着不同程度的影响,优化的工艺参数组合可以使塑件翘曲变形达到最小,从而提高塑件质量。     

基于Moldflow的汽车水箱盖注射成型工艺参数优化设计

利用Moldflow软件对汽车水箱盖成型过程进行数值分析,以降低塑件翘曲量为目标,利用正交试验法分析主要成型工艺参数对翘曲变形的影响规律,获得最佳工艺参数组合。研究结果表明:工艺参数对翘曲变形影响程度从大到小依次为保压压力、保压时间、熔体温度、冷却时间、模具温度、注射时间,参数优化后的塑件最大翘曲量为1.148 mm。     

U盘上盖的翘曲变形分析与工艺参数优化

以U盘上盖的注塑成型为实例,运用Taguchi试验设计法,结合信噪比(S/N)和变量分析方法(ANOVA),以减少塑件的翘曲量为目的,研究熔体温度、模具温度、保压压力和保压时间等工艺参数对塑件翘曲的影响,分析各工艺参数的影响程度,并优化成型工艺。结果表明:保压压力、熔体温度对塑件翘曲变形影响最大,优化后的塑件翘曲量降低了约16%。     

基于Taguchi试验的塑件翘曲分析及工艺优化

为减小手机壳体成型时翘曲变形量,利用Taguchi试验设计和变异数分析进行翘曲因素分析和优化成型工艺参数。将熔体温度、模具温度、注射时间、保压压力、保压时间、V/P切换等工艺参数作为翘曲的影响因子,设计了5水平Taguchi试验矩阵L_(25)(5~6),并采用Moldflow软件进行模拟试验。利用信噪比(S/N)衡量塑件Z方向翘曲变形量的大小,信噪比越大,翘曲变形量越小。通过对信噪比均值分析,建立因子影响趋势图,获得最优工艺参数组合为A1B1C4D4E5F5。通过变异数分析的方法分析了各工艺参数对塑件Z方向翘曲变形的影响程度,其中保压时间是最显著因素,延长保压时间至6s时,塑件Z方向翘曲变形量最小。经试验验证,Taguchi试验和变异数分析是解决翘曲变形的有效方法。     

应用Taguchi实验设计法最小化ABS注塑制品翘曲变形量

运用Taguchi DOE技术研究了工艺参数对丙烯腈-丁二烯-苯乙烯共聚物(ABS)注塑制品翘曲变形的影响,并获得优化的工艺参数以使制品的翘曲变形量最小。文中以碱性蓄电池盖为例,利用L9(34)正交矩阵进行实验,并采用标准变量分析法(ANOVA)对熔体温度、注射时间、冷却时间、保压压力等工艺参数对制品翘曲变形的影响程度进行了研究,结果表明,在所选工艺参数中,保压压力和熔体温度对翘曲变形的影响程度最大。     

基于正交试验的端盖注塑件优化

以端盖注塑件为例,运用正交试验结合CAE模拟技术,研究定模温度、动模温度、熔体温度、螺杆速度及位置、保压时间和压力对塑件翘曲变形的影响规律,优选出对翘曲变形量影响最小的工艺参数组合。在此基础上,利用复合形法对影响翘曲变形量最大的3个因素（定模温度、保压时间、保压压力）进行优化设计,从而进一步减小塑件翘曲变形量。     

薄壁塑件注射工艺参数的Taguchi方法优化

利用Moldflow软件,结合Taguchi法选择三因素(模具温度、熔体温度、保压方式)三水平对手机电池后盖的翘曲变形进行了研究。通过比较9种组合工艺的塑件翘曲变形量,得出了优化的工艺参数。优化后塑件的最小翘曲变形量为0.306 4 mm,比优化前降低了11.6%。从显著性检验看,熔体温度对零件的翘曲变形有显著影响,模具温度和保压方式对零件翘曲变形影响不显著。     

基于Taguchi的水壶塑件注射工艺参数优化

以水壶塑件为研究对象,应用Moldflow有限元分析软件,针对塑件质量缺陷或问题产生的原因,合理设计了模具浇注系统和温度调节系统。以翘曲变形量作为质量指标,采用多因素Taguchi法,获得了塑料在熔料温度、模具温度、保压压力、保压时间、冷却时间五因素四水平下成型塑件的翘曲变形量。采用方差分析法比较了不同工艺参数对翘曲变形量的影响程度,得到了优化的工艺参数组合。     

基于稳健设计的电器壳体注塑成型工艺参数优化

将Taguchi稳健设计和CAE模拟技术相结合,应用于注塑工艺参数的优化。以某电器壳体的注塑成型为例,以减小制品的翘曲变形为试验目标,研究模具温度、熔体温度、注射时间、保压压力及浇口位置对注塑件翘曲变形的影响规律,运用变量分析,确定工艺参数对翘曲变形的影响度。     

基于正交法塑料支撑件注射工艺参数优化研究

应用Moldflow有限元分析软件,针对支撑件产生缺陷的原因,合理设计模具的浇注系统和温度调节系统,以翘曲变形量作为质量指标,采用多因素正交法获得塑件在熔料温度、模具温度、保压压力、保压时间、注射时间五因素四水平下成型的翘曲变形量,采用方差分析比较了不同工艺参数对翘曲变形量的影响程度,得到了优化的工艺参数组合。     

电位对天然黄铜矿表面膜层性质的影响

采用循环伏安（CV）、扫描电子显微镜（SEM）和电化学阻抗谱（EIS）研究黄铜矿在含有5×10-4mol/L乙黄药溶液中的电化学行为以及电位对黄铜矿表面膜层成分和性质的影响。结果表明：在开路电位（OCP）下,天然黄铜矿表面发生黄药阴离子的吸附过程;在阳极电位范围-0.11～0.2V内,主要发生黄药阴离子氧化形成疏水双黄药膜层的电化学过程。形成的双黄药膜层在电位为0V时具有较高覆盖度和较大的厚度,随着电位的增加表面双黄药膜层的覆盖度和厚度减小。当电位高于0.2V时,黄铜矿表面发生以自身活化溶解为主的电化学过程,黄铜矿表面由双黄药膜层转化成为大量具有多孔和疏松结构的含有Cu（Ⅱ）和Fe（Ⅲ）的氧化物。     

Studies on the Influence of Hexadecylamine on Chromate Phosphate Coating on Aluminium

The effect of hexadecylamine (HDA) on a Chromate phosphate coating on aluminium was studied using an optimized Chromate phosphate bath, The addition of HDA was found to decrease the coating weight, but to enhance the coating quality and corrosion resistance. The inhibitory effect of HDA helps in regulating the excessive attack on the metal and its ability to reduce Cr⁶⁺ to Cr³⁺ compensates the possible time delay for the initiation of coating deposition due to the inhibition.     

Effects of ring substituents on the protective properties of self-assembled benzenethiols on copper

The self-assembled monolayers (SAMs) of a series of substituted benzenethiol (BT) molecules, X-C₆H₄-SH (where X = meta-NH₂, ortho-NH₂, para-NH₂, para-NHCOCH₃, para-F, para-CH₃ and para-CH(CH₃)₂), have been prepared by adsorption from a solution onto a fresh copper (Cu) surface pretreated by a nitric acid etch. The corrosion inhibition efficiency of the modified Cu surfaces in a sulfuric acid solution was investigated by electrochemical characterization. The protection afforded by the substituted functional groups on BT is strongly influenced by the type and the position of the substituent on the benzene ring. BT molecules without any substituent group on the ring are ineffective corrosion inhibitors, indicating that the chemical configuration is the key factor in determining the efficacy of the SAMs as barriers to electrochemically corrosive ions. It is further proposed that the steric hindrance offered by the substituted group in the SAMs plays a very important role in determining its barrier properties.     

Effect of Aluminium Sec-butoxide on Wetting Properties of Silica-Based Coatings on Glass

Many surface properties are more or less strongly controlled by the surface pattern, i.e., the micro or nanoscale morphologies. Silica-alumina mixed oxide coatings were prepared by simple sol-gel method using methyl trimethoxysilane (MTMS) and aluminium sec-butoxide (ASB) as precursors. To obtain good quality coatings the volume ratio of MeOH:MTMS:HNO₃:H₂O:NH₄OH was optimized at 10:2.5:0.3:1:4 and the ASB:MTMS ratio (M) was varied from 0.25 to 1. The effect of M on surface roughness and thus on wetting behavior of the coatings was studied. For M = 0.25 and 1, the water contact angle was 95° and 104° while the same for M = 0.5 was 116°. The variation in water contact angle is supported by surface morphology and surface roughness. The presence of aluminium and silica cross linkage was detected by FT-IR and XRD patterns as well.     

Effect of additives on the properties of phosphate conversion coating on electrogalvanized steel sheet

Ni²⁺ and Mn²⁺ ions have been added separately to the phosphate solution to minimize the porosity of the phosphate conversion coating on electrogalvanized steels. Results showed that the Ni²⁺ or Mn²⁺ in the solution reduced the grain size and porosity of the phosphate coating; thereby, the corrosion resistance was enhanced. However, Ni²⁺ and Mn²⁺ played a different role in the coating formation. Ni²⁺ in the solution was reduced by Zn to form Ni, which enhanced the dissolution of Zn to promote the nucleation of hopeite grains. Mn²⁺ in the solution facilitated the nucleation by increasing the impingement of reacting species.     

Effect of voltage on microstructure and corrosion resistance of microarc oxidation coatings on CP-Ti

The surface modification of commercially pure titanium (CP-Ti) by microarc oxidation (MAO) under different voltages was investigated using 1%H₃PO₄ solution as an electrolyte. The microstructure, phase composition and elemental distribution of ceramic coatings were investigated using scanning electron microscopy (SEM) and X-ray diffraction. The corrosion behaviour of the coating was also examined by potentiodynamic polarisation testing in a 3·5 wt-%NaCl solution. Micropore oxide films were formed on all the sample groups by MAO. The thickness and micropore size of the MAO coating increased with the increasing voltage. Energy dispersive X-ray spectroscopy results indicate that Ti, O and P became incorporated into the MAO coatings. At a low voltage of 250 V, the MAO coatings were composed of amorphous, P₂O₅, TiP₂O₇ and titania phases (rutile and anatase). Variation of treatment voltages increased the ceramic coatings from an amorphous structure to a phase structure, and the P₂O₅ phase disappeared. The corrosion potential Φ_corr of the MAO sample shifted towards nobler directions, and the corrosion density I_corr fell significantly compared with that of the bare CP-Ti. Corrosion testing showed that the sizes of the micropore of the MAO samples obviously decrease, and the MAO surface becomes smooth.     

锌对SnxZn/Cu界面微空洞的影响

通过向锡钎料中添加不同含量的Zn元素,系统研究了锌对SnxZn/Cu(x=0,0.2,0.5,0.8(质量分数,％))界面处柯肯达尔空洞形成的影响.结果表明,经热老化处理后,纯Sn/Cu接头中的Cu3 Sn层和Cu3 Sn/Cu界面出现了大量柯肯达尔空洞.然而随着Zn元素含量的增加,反应界面处的Cu3Sn层逐渐变薄甚至消失,柯肯达尔空洞也随之显著减少或消失;锌在反应界面处的富集现象越来越显著.锌参与了界面反应,形成了(Cu,Zn)6Sn5相、Cu6(Sn,Zn)5相和Cu-Zn固溶合金,其中Cu-Zn固溶合金层可以显著影响铜的界面扩散.Zn元素直接参与了界面扩散,在很大程度上缓和铜和锡的不平衡扩散,从而有效抑制了柯肯达尔空洞的形成.     

Effect of chloride concentration on passive film properties on copper

The semiconducting properties of passive films formed on copper, in anaerobic alkaline sodium chloride solution, were studied using Mott–Schottky analysis and electrochemical impedance spectroscopy, based on the point defect model. Results showed that the corrosion resistance increased with increasing potential, which was attributed to a well crystallised, refined grain structure, and a thicker passive film at higher potential. P-type semiconducting characteristics were obtained with or without chloride. The density of copper vacancies was approximately 10²⁰?cm^?3, and increased with the increasing chloride concentration, which was attributed to faster film-formation in a higher chloride environment. The diffusion coefficient of the defects, a key dynamic parameter for passive film breakdown, was in the range of 10^?16–10^?15?cm²?s^?1, and increased with increasing chloride concentration, thus leading to a greater probability of pitting.     

Detrimental role of LiOH on the oxide film formed on Zircaloy-4

To understand the degradation behavior of Zircaloy-4 corroded in LiOH aqueous solution, X-ray diffraction was performed to analyze the crystal structure of Zircaloy-4 oxide formed in three different media. Second ion mass spectrometry (SIMS) was utilized to measure the penetration of Li⁺ and OH⁻ into the oxide film when Zircaloy-4 is exposed in LiOH aqueous solution. It was found that the SIMS depth profile of OH⁻ in the oxide film is in accord with that of Li⁺, which indicates that there exists OH⁻ in the oxide film. Based on the results, it is put forward that OH⁻ diffuses faster than O⁻² in the oxide films, which can enhance the corrosion rate of Zircaloy-4 and the transformation from tetragonal zirconia (t-ZrO₂) to monoclinic zirconia (m-ZrO₂). OH⁻ plays a detrimental role on the oxide film formed on Zircaloy-4.     

Effect of substrate oxidation on spreading of plasma-sprayed nickel on stainless steel

Plasma-sprayed, molten nickel particles (∼ 60 μm diameter) were photographed during impact on oxidized 304L stainless steel surfaces that were maintained at either room temperature or at 350 °C. Steel coupons were oxidized by heating them at different temperatures. A fast charge-coupled device (CCD) camera captured time-integrated images of the spreading splat. A two-color pyrometer collected thermal radiation from particles and recorded the evolution of their temperature after impact. Molten nickel particles impacting on oxidized steel at room temperature fragmented significantly, while heating the surfaces produced splats with disk-like morphologies. Impact on steel that was highly oxidized induced the formation of finger-like splash projections at the splat periphery. Thermal contact resistance between splats and non-heated oxidized steel was calculated from splat cooling rates and found to decrease as the degree of oxidation increased. On heated, oxidized steel thermal contact resistance was much lower and did not change significantly with the degree of oxidation. It was concluded that thermal contact resistance was largely influenced by adsorbates on the steel surface that evaporated when the surface was heated or oxidized.