全自动注射模内剪切浇口技术研究

通过对模具内自动切除浇口的分析,阐述了其优越性与发展趋势。举例分析了模具内冷切浇口的两种方法,设计了模具内热切浇口的方法,并分析了其公差配合要点,总结了模具内热切浇口的优点和缺点。可供从事注射模设计和制造的工程技术人员参考和借鉴。     

塑料注射模点浇口及其凝料自动脱落机构设计

详细地阐述了塑料注射模点浇口的设计,点浇口浇注系统凝料自动拉断和脱落的各种机构设计,点浇口自动脱落机构在模具上相关件尺寸的确定,对于该类模具的设计具有指导意义。     

点浇口注射模浇注系统自动脱模的设计

通过分析点浇口注射模具浇注系统的结构特点,设计了4种点浇口浇注系统的自动脱模机构,并详细地叙述了浇注系统自动脱模的工作过程,这些机构制造方便,动作可靠,能使点浇口模具全自动生产,提高了生产效率。     

面框注射成形浇口的改进设计

手机面框注射成形模具的浇口设计,不仅决定了制件的精度和外观,而且影响到产品二次加工的方便性.分析此类模具的设计,发现浇口采用侧浇口、搭肩进胶和牛角进胶形式,容易产生浇口去除痕迹、产品变形严重,以及二次加工工艺性不好等一系列缺陷.通过改进浇口形式,采用类似牛角进胶,但是浇口尺寸加大,进胶浇道从斜销的下面绕过进入制件.增设斜销出模机构,使模具开模时,斜销运动给浇口让出位置,确保浇道凝料脱模时能跟产品连在一起.满足了浇口痕迹小的外观要求,而且浇道凝料在产品二次加工中能够辅助定位和固定,起浇注和工艺二重作用.     

长锥形潜伏浇口在深长形塑件注射模中的应用

介绍长锥形潜伏浇口在深长形塑件注射模中的应用。分析了长锥形潜伏浇口的几种形式并介绍了相关设计参数。模具结构简单，节省模具开发成本，缩短了成型周期。     

从塑件质量谈注射模浇口位置的选择

在注射模设计中,浇口位置的确定是一个很重要的设计变量,它与塑件的尺寸形状、模具结构、注射工艺条件及塑件性能等因素有关。不当的浇口位置直接影响到塑件的质量和性能。介绍了注射模浇口位置选择时应注意的问题,结合具体的塑件,从质量要求方面论述了如何确定浇口位置,并提出了最佳浇口位置的建议,为注射模设计者提供了方便而实用的参考依据。     

点浇口注射模分型装置的设计

<正> 1 引言对盒形、帽形及外形有要求的塑件,一般都采用点浇口注射模成型。而点浇口注射模的模具结构又属3次分型结构:第1次靠机床分型将分流道料把与制品分开:第2次靠开模装置将主流道料把从浇口套中脱出:第3次靠机床顶出机构将制品顶出模具。模具的设计合理与否,对提高模具的使用寿命,缩短制品注射周期,提高生产效率和自动化程度具有重要的意义。     

模内自动冲切浇口凝料机构的微流控芯片注射模设计

以具有微纳米结构的碟形微流控芯片为研究对象,设计了具有模内自动冲切浇口的注射成型模具。通过对碟形微流控芯片注射时熔体流动均匀性和散热翘曲分析,注射成型模具采用1模1腔的形式,注射浇口选择盘形浇口,冷却水道采用环形水道。为了提高生产效率,降低后续消除浇口对芯片造成的二次破坏,注射模中增加了模内自动切浇口凝料机构,以实现开模前完成浇口凝料切除,并用工具显微镜观察切口成型质量。     

洗衣机空气管注射模型芯偏移的CAE分析研究

运用Moldflow软件模拟洗衣机空气管注射模型芯偏移问题,通过模拟分析,调整注射模的浇口位置,确定了使型芯产生偏移量最小的浇口位置。进一步研究了浇口位置对模具型芯偏移的影响趋势,注射压力与模具型芯偏移的关系和型芯偏移量与Von Mises应力对应关系。最终选择优化方案对模具进行整改,避免了原模具生产塑件存在的缺陷。     

手机背夹电池后盖注射模设计

分析了手机背夹电池后盖的结构特点,设计了1副三板模,模具浇注系统为点浇口转侧浇口,针对塑件材料PC吸湿性和水敏性的特点,还设计了排气系统。模具投入实际生产,运行情况良好,成型的塑件外观完整,质量稳定,废品率低。     

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.     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。