数控铣床加工轮轴零件的专用夹具设计

在批量机械零件加工中,为了提高零件的加工质量和生产效率,以及降低生产成本,通常会想方设法对一些通用夹具进行改装或者设计制造一些专用夹具,使工件在装夹时既快又稳,而在数控机床上加工工件时,这些改装过的通用家具和设计的专用夹具就更能充分发挥数控机床加工潜力,提高生产效率,保证加工精度,甚至扩大机床的使用范围。根据轮轴零件的工艺要求,设计了一套其在数控铣床上加工的专用夹具,实现了轮轴零件在数控铣床上优质、高效、多件同时加工,提高了生产效率和加工质量。     

精密线切割专用夹具设计

以提高精密线切割的加工效率、零件的加工品质,降低相关配套夹具成本为目的,展示了通用性夹具在设计开发时所考虑的通用性,在实际生产使用过程中所存在的实际问题,以及专用夹具的高昂价格。结合零件精度的实际需求,参考相关夹具设计理念,设计了一款适合精密线切割机台专用夹具:该专用夹具容易制造,装夹、调节简单,实用性强,制造成本低廉,装夹精度高。     

基于CAE和神经网络的切削参数优化

提出了一种以变形加工误差为约束的基于有限元分析和神经网络的切削参数优化方法.针对复杂工件夹具系统在切削过程中的变形问题进行有限元刚度计算,然后通过神经网络的方法拟合切削参数和工件夹具系统变形误差之间的关系.并以加工生产效率最大化为目标,在保证加工精度的前提下优化切削参数.从而实现以工艺成本最小化来提高零件的加工精度.     

燃气分配器高精密阀口加工的改进

现有一款产品的加工尺寸、形状和粗糙度要求都非常高,定位难度较大,设计一套较为方便的自动化工装夹具和成型刀具配合加工是非常必要的。该夹具利用气缸、模型工装和支架组合而成,定位精度高,装夹速度快,不仅提高了零件的加工质量和生产效率,而且降低了员工的劳动强度。     

薄壁框体零件加工工艺分析及其专用夹具的设计研究

薄壁框体零件形状复杂、精度要求较高,其加工工艺和装夹方式直接影响零件生产的质量及效率。通过对薄壁框体零件加工难度的分析、加工工艺的制定、专用夹具的设计及铣削加工时应注意的问题进行研究,解决了薄壁框体零件加工易变形、定位及装夹难等问题,保证了零件加工质量,提高了生产效率。     

轿车排气系统机器人焊接夹具的设计要点及柔性化

由于现代社会汽车产业快速发展,车型更新换代很快,对于稳定产品质量、提高生产效率、降低生产成本的要求越来越高.工业机器人在此方面起着不可替代的作用.而符合轿车产品特点、高质量、高柔性的夹具设计已经成为决定弧焊机器人设备能否高效、合理应用的核心问题.根据轿车排气系统的结构和特性,按照从热端到冷端的顺序,着重介绍了轿车排气系统焊接夹具从工件总成中每个零件定位方式的选择,到整体定位方式的选择阐述了夹具的设计思路,同时也介绍了夹具在设计方面应该注意的事项.另外根据产品的多样性对夹具的柔性化设计做了简单阐述.对机器人在轿车排气系统方面的应用有一定参考价值.     

信息动态

针对数据线“三明治”结构的超声波焊接,设计了自动焊接系统.通过外壳储料仓和料回收一次性人工上、下多批料,机械人自动抓取物料,夹具自动夹紧定位,超声波完成焊接后,自动下料,节约人力成本.为提高生产效率,采用多个随行夹具配合工位转盘结构,节约焊接时间,提高生产效率.     

动力转向器输入轴钻斜油孔专用夹具设计

针对动力转向器输入轴外圆表面形状复杂,斜油孔加工时手动分度机构定位精度不高和生产效率低下的问题,合理选择定位基准并设计了在立式数控钻床上使用的专用夹具。阐述了夹具的结构特点及工作原理,对定位误差进行分析和控制。采用伺服电机实现数控分度,基于CAE软件SolidThinking Inspire对夹具体进行了轻量化设计。通过简单调整和更换夹具部分元件可实现成组加工,一次装夹加工出工件圆周方向均布的三个斜油孔,提高了生产效率和自动化水平,降低了夹具制造成本,能够满足多品种生产的要求。     

铣削加工生产中成组夹具设计

根据当前单件、小批量、多品种生产的需要,设计一种用于铣加工的成组夹具.实践证明:该套夹具投入使用后,满足了大多数小批量零件的机加工要求,保证了工件的加工精度,缩短了生产周期,提高了加工效率.     

基于嵌条压板零件的加工工艺分析与专用夹具设计

通过对数控加工中心的压紧零件嵌条压板的分析,制定工艺路线,并对其中第7、8道工序进行专用夹具设计,实现批量生产,提高生产效率,并为相关零件的加工工艺设计及夹具设计提高参考.     

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。